Article

Global wildland fire season severity in the 21st century

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Given the strong relationship between fire and climate, climate change resulting from increased greenhouse gas emissions is expected to alter the spatial distribution of fire activity. Some studies point to increases in the severity of the fire season (FS) 17 and the wildfire potential 18 , and a gradual shift to a global fire regime dominated by temperature 19 , rather than precipitation or human factors, at the end of the 21st century. However, the magnitude and location of change is still debated for many parts of the world 20 . ...
... There is evidence, however, that temperature increases may lead to drier fuels in the future despite the precipitation increase, thus augmenting fire risk, as some investigations have shown for Canada 41 . Our results agree in general with several other studies that have previously pointed towards an increase of the FSL in boreal areas 1,17,42 , even when some suggest a more pronounced lengthening in more northerly latitudes 1,17 . In terms of the frequency of years with fire-prone conditions, the conclusions are even clearer. ...
... There is evidence, however, that temperature increases may lead to drier fuels in the future despite the precipitation increase, thus augmenting fire risk, as some investigations have shown for Canada 41 . Our results agree in general with several other studies that have previously pointed towards an increase of the FSL in boreal areas 1,17,42 , even when some suggest a more pronounced lengthening in more northerly latitudes 1,17 . In terms of the frequency of years with fire-prone conditions, the conclusions are even clearer. ...
Article
Full-text available
Global warming is expected to alter wildfire potential and fire season severity, but the magnitude and location of change is still unclear. Here, we show that climate largely determines present fire-prone regions and their fire season. We categorize these regions according to the climatic characteristics of their fire season into four classes, within general Boreal, Temperate, Tropical and Arid climate zones. Based on climate model projections, we assess the modification of the fire-prone regions in extent and fire season length at the end of the 21st century. We find that due to global warming, the global area with frequent fire-prone conditions would increase by 29%, mostly in Boreal (+111%) and Temperate (+25%) zones, where there may also be a significant lengthening of the potential fire season. Our estimates of the global expansion of fire-prone areas highlight the large but uneven impact of a warming climate on Earth’s environment.
... Indeed, burnt areas have already increased across parts of the globe over the last decades and are expected to keep growing over the century (Abatzoglou and Williams 2016;Amatulli et al. 2013), as the potential for large fires (Barbero et al. 2015;Ruffault et al. 2020). Fire seasons are expected to lengthen and fire prone areas are expected to expand (Flannigan et al. 2013), but the magnitude, location and timing of such increases remain uncertain, especially in the Mediterranean area. Moreover, an intensification is expected during the core of the fire season of already fire-prone regions, which should become more severe (Dong et al. 2022;Senande-Rivera et al. 2022). ...
... For all fire activity metrics, the increase was faster than the one of the mean FWI (1.76 folds) and even DSR (2.2), except for 1ha fires which increased slower than the DSR. This is an important result, as the mean DSR -also called SSR-is often used to estimate the difficulty to control fires and seasonal length (Flannigan et al. 2013). ...
Chapter
O período entre 2018 e 2022 mostrou-nos que o problema dos incêndios à escala global não está a diminuir, antes pelo contrário. Parece que as consequências das alterações climáticas já estão a afectar a ocorrência de incêndios florestais em várias partes do Mundo, de uma forma que só esperaríamos que acontecesse vários anos mais tarde. Em muitos países do Sul da Europa, bem como em algumas regiões dos EUA, Canadá e Austrália, onde estamos habituados a enfrentar a presença de incêndios muito grandes e devastadores, continuamos a ter eventos que quebram recordes. Alguns países, como os da Europa Central e do Norte, que não estavam habituados a ter grandes incêndios, experimentaram-nos durante estes anos. Os anos anteriores foram muito exigentes para todo o Mundo, também noutros aspectos que nos afectaram a todos. Referimo-nos às restrições impostas pela pandemia que limitaram as nossas reuniões e viagens, afectando em muitos casos a saúde dos membros da Comunidade Científica Wildfire. Felizmente, conseguimos encontrar novas formas de comunicação, ultrapassar essas limitações e manter-nos em contacto uns com os outros. Durante semanas e meses, para muitos de nós, as reuniões pessoais e o trabalho de grupo foram substituídos por ligações em linha. Apesar da economia de dinheiro e tempo, e da facilidade de reunir uma grande variedade de pessoas que estas reuniões desde que nos apercebêssemos de que não substituem as reuniões presenciais, que trazem consigo outras dimensões inestimáveis, que fazem parte da comunicação pessoal e ajudam a construir uma comunidade científica.
... While it is still under debate whether the global area burnt by wildfires increases 16 , modelling studies show that intense fires will occur more frequently in a warming climate 17 . This implies that wildfires will become an increasingly relevant aspect of near-term climate variability in the stratosphere. ...
... The results indicate that the imprint from the Australian wildfires is the strongest stratospheric climate signal caused by aerosols since the eruption of the Pinatubo in 1991. While volcanic eruptions occur on an irregular basis and are not influenced by human action, the risk of intense wildfires increases due to climate change 1,17 . Therefore, the impact of wildfires is expected to become increasingly important. ...
Article
Full-text available
Wildfires are expected to become more frequent and intense in the future. They not only pose a serious threat to humans and ecosystems, but also affect Earth’s atmosphere. Wildfire plumes can reach into the stratosphere, but little is known about their climate impact. Here, we reveal observational evidence that major wildfires can have a severe impact on the atmospheric temperature structure and short-term climate in the stratosphere. Using advanced satellite observation, we find substantial warming of up to 10 K of the lower stratosphere within the wildfire plumes during their early development. The short-term climate signal in the lower stratosphere lasts several months and amounts to 1 K for the Northern American wildfires in 2017, and up to striking 3.5 K for the Australian wildfires in 2020. This is stronger than any signal from recent volcanic eruptions. Such extreme events affect atmospheric composition and climate trends, underpinning their importance for future climate.
... Hundreds have lost their lives and thousands have been left homeless [25,9]. Climate changes have become increasingly prominent and there appears to be consensus about future development, resulting in increased wildfire seasons and frequency [7,13,4,11,10,25,8]. Much attention is paid to these devastating fires, however, from the above 300,000 ...
... Hundreds have lost their lives and thousands have been left homeless [25,9]. Climate changes have become increasingly prominent and there appears to be consensus about future development, resulting in increased wildfire seasons and frequency [7,13,4,11,10,25,8]. Much attention is paid to these devastating fires, however, from the above 300,000 annual deaths caused by fire, the majority occurs within enclosures, such as a residence [26]. ...
Article
The high and dense representation of wooden homes in Norway, combined with periods of dry and cold climate during the winter season resulting in very dry indoor conditions, have historically resulted in severe fires. Thus, it is important to have an accurate estimate of the current and near future fire risk to take proper planning precautions. Cloud computing services providing access to weather data in the form of measurements and forecasts combined with recent developments in fire risk modelling may enable smart and fine-grained fire risk predication services. The main contribution of this study is implementation and experimental validation of a predictive fire risk indication model, which exploits cloud-provided measurements from weather stations and weather forecasts to predict the current and future fire risk for wooden homes at a given geographical location. The basic idea of the model is to estimate the indoor climate using measured and forecasted outdoor climate for computing indoor wooden fuel moisture content and an estimated time to flashover as indication of the fire risk. The model implementation was integrated into a micro-service based software system and experimentally validated during one winter at selected geographical locations, relying on weather data provided by the RESTful API of the Norwegian Meteorological Institute. Additionally, weather data from several historical fires were considered to relate our predictions to known fire incidents. Our evaluation demonstrates the ability to provide trustworthy and accurate fire risk indications using a combination of weather data measurements and forecast data. Furthermore, our cloud-and micro-service based software system implementation is efficient with respect to data storage and computation time.
... Consequently, carbon (C) emissions from boreal wildfires have been considered to be dominated by top-down controls of fire-conducive weather [5][6][7] . The Canadian Forest Fire Weather Index (FWI) System 8 is widely used to predict fire activity and C emissions throughout the boreal forest and even globally [9][10][11] and consists of six components that reflect landscape-level effects of weather on fuel moisture and fire behaviour 12 . However, bottom-up controls of fuel characteristics and topo-edaphic variation are also likely to be important drivers of C emissions from wildfires 13,14 . ...
... Furthermore, any fine-scale variation that does exist in FWIs is small relative to the temporal and coarse-scale spatial variation used in this study (see 'Sources of variation in FWIs' section of Supplementary Information and Supplementary Table 4). Our use of coarse-resolution climate data is consistent with prior work modelling fire activity and C emissions throughout the boreal forest [9][10][11] . Although there are uncertainties with our measurements of pre-fire conditions, modelled estimates of C pools and C combustion, and interpolated FWI System components, the methods used to obtain these variables were comparable between ecoregions. ...
Article
Full-text available
Carbon (C) emissions from wildfires are a key terrestrial–atmosphere interaction that influences global atmospheric composition and climate. Positive feedbacks between climate warming and boreal wildfires are predicted based on top-down controls of fire weather and climate, but C emissions from boreal fires may also depend on bottom-up controls of fuel availability related to edaphic controls and overstory tree composition. Here we synthesized data from 417 field sites spanning six ecoregions in the northwestern North American boreal forest and assessed the network of interactions among potential bottom-up and top-down drivers of C emissions. Our results indicate that C emissions are more strongly driven by fuel availability than by fire weather, highlighting the importance of fine-scale drainage conditions, overstory tree species composition and fuel accumulation rates for predicting total C emissions. By implication, climate change-induced modification of fuels needs to be considered for accurately predicting future C emissions from boreal wildfires.
... Recent global studies demonstrate that annual burned area has decreased in recent decades 6 , while extreme wildfire events are becoming more frequent and intense [6][7][8] . Drivers of these trends include fragmentation of fuel landscapes with land use change, accumulation of flammable vegetation after suppression of human fire use and lengthening fire weather windows due to climate change 9,10 . In this context we need to better understand how smallholder and subsistence livelihood-oriented fire use is currently changing and the implications for fire ecologies, human well-being and wildfire events 11 . ...
Article
Full-text available
Human use and management of fire in landscapes have a long history and vary globally in purpose and impact. Existing local research on how people use and manage fire is fragmented across multiple disciplines and is diverse in methods of data collection and analysis. If progress is to be made on systematic understanding of human fire use and management globally, so that it might be better represented in dynamic global vegetation models, for example, we need improved synthesis of existing local research and literature. The database of anthropogenic fire impacts (DAFI) presented here is a response to this challenge. We use a conceptual framework that accounts for categorical differences in the land system and socio-economic context of human fire to structure a meta-study for developing the database. From the data collated, we find that our defined anthropogenic fire regimes have distinct quantitative signatures and identify seven main modes of fire use that account for 93% of fire instance records. We describe the underlying rationales of these seven modes of fire use, map their spatial distribution and summarise their quantitative characteristics, providing a new understanding that could become the basis of improved representation of anthropogenic fire in global process-based models. Our analysis highlights the generally small size of human fires (60% of DAFI records for mean size of deliberately started fires are <21 ha) and the need for continuing improvements in methods for observing small fires via remote sensing. Future efforts to model anthropogenic fire should avoid assuming that drivers are uniform globally and will be assisted by aligning remotely sensed data with field-based data and process understanding of human fire use and management.
... Therefore, there is an inherent trade-off between the success of these key post-fire recovery strategies, with the potential to impact species composition under persistent changes in fire seasonality. Climate change is shifting the timing and length of global fire seasons [56][57][58] , and the findings of this meta-analysis indicate that such shifts may have broad and interacting effects across many regions and across a range of major plant functional types. ...
Article
Full-text available
Wildfires are increasing in size and severity and fire seasons are lengthening, largely driven by climate and land-use change. Many plant species from fire-prone ecosystems are adapted to specific fire regimes corresponding to historical conditions and shifts beyond these bounds may have severe impacts on vegetation recovery and long-term species persistence. Here, we conduct a meta-analysis of field-based studies across different vegetation types and climate regions to investigate how post-fire plant recruitment, reproduction and survival are affected by fires that occur outside of the historical fire season. We find that fires outside of the historical fire season may lead to decreased post-fire recruitment, particularly in obligate seeding species. Conversely, we find a general increase in post-fire survival in resprouting species. Our results highlight the trade-offs that exist when considering the effects of changes in the seasonal timing of fire, an already present aspect of climate-related fire regime change. Post-fire recovery success after fires that occur outside of the historical fire season varies between fire response traits, which may impact long term ecosystem composition under changing fire regimes, according to a global systematic meta-analysis.
... Recent global studies demonstrate that annual burned area has decreased in recent decades 6 , while extreme wildfire events are becoming more frequent and intense [6][7][8] . Drivers of these trends include fragmentation of fuel landscapes with land use change, accumulation of flammable vegetation after suppression of human fire use and lengthening fire weather windows due to climate change 9,10 . In this context we need to better understand how smallholder and subsistence livelihood-oriented fire use is currently changing and the implications for fire ecologies, human well-being and wildfire events 11 . ...
Article
Full-text available
Controlled fire use for hunting, gathering, smallholder agriculture and pastoralism shapes ecologies and enhances livelihoods worldwide. Yet, at global scale, we know little about how these practices influence human well-being, ecologies and wildfire risk. As a basis for global syntheses, we collated information from the literature about fire practices in 587 case study locations spanning the globe. Here, we assess the coverage and completeness of these data. Limited quantitative data, particularly, present a challenge for improved modelling of anthropogenic influences on fire regimes. We also analyse global trends in fire practices from these studies, finding evidence that subsistence-oriented fire practices have declined in recent decades, while market-oriented fire practices have increased. Implications of these changes can include reduced biodiversity in fire-dependent ecosystems, increased wildfire risk, reduced household income and loss of cultural identity. The case studies point to important drivers of changing fire practices, especially economic pressures and state governance.
... Wildfire is a normal occurrence in high-latitude permafrost regions, particularly in the boreal forest. However, larger and more severe fires have been observed in response to warmer and drier conditions, and fire activity is projected to increase further with continued warming 106,107 . These fires damage the protective surface organic layer that insulates the ground from warm summer air temperatures, decrease the amount of snow interception by trees, decrease the albedo at the ground surface, and decrease cooling by evapotranspiration [107][108][109][110] . ...
Article
Permafrost temperatures have increased in polar and high-elevation regions, affecting the climate system and the integrity of natural and built environments. In this Review, we outline changes in the thermal state of permafrost, focusing on permafrost temperatures and active-layer thickness. Increases in permafrost temperature vary spatially owing to interactions between climate, vegetation, snow cover, organic-layer thickness and ground ice content. In warmer permafrost (temperatures close to 0 °C), rates of warming are typically less than 0.3 °C per decade, as observed in sub-Arctic regions. In colder permafrost (temperatures less than −2 °C), by contrast, warming of up to about 1 °C per decade is apparent, as in the high-latitude Arctic. Increased active-layer thicknesses have also been observed since the 1990s in some regions, including a change of 0.4 m in the Russian Arctic. Simulations unanimously indicate that warming and thawing of permafrost will continue in response to climate change and potentially accelerate, but there is substantial variation in the magnitude and timing of predicted changes between different models and scenarios. A greater understanding of longer-term interactions between permafrost, climate, vegetation and snow cover, as well as improved model representation of subsurface conditions including ground ice, will further reduce uncertainty regarding the thermal state of permafrost and its future response.
... Increasing fuel aridity (F) and fire-weather extremes with continued climate change portend increased wildland fire activity where biomass is abundant and flammability is a primary constraint 8,9 , including in western US forests 1,3 . Warming directly enhances fuel aridity by increasing the vapor pressure deficit (VPD) as well as reducing snowpack in montane regions, which collectively intensify and lengthen the fire season. ...
Article
Full-text available
Escalating burned area in western US forests punctuated by the 2020 fire season has heightened the need to explore near-term macroscale forest-fire area trajectories. As fires remove fuels for subsequent fires, feedbacks may impose constraints on the otherwise climate-driven trend of increasing forest-fire area. Here, we test how fire-fuel feedbacks moderate near-term (2021–2050) climate-driven increases in forest-fire area across the western US. Assuming constant fuels, climate–fire models project a doubling of forest-fire area compared to 1991–2020. Fire-fuel feedbacks only modestly attenuate the projected increase in forest-fire area. Even models with strong feedbacks project increasing interannual variability in forest-fire area and more than a two-fold increase in the likelihood of years exceeding the 2020 fire season. Fuel limitations from fire-fuel feedbacks are unlikely to strongly constrain the profound climate-driven broad-scale increases in forest-fire area by the mid-21st century, highlighting the need for proactive adaptation to increased western US forest-fire impacts. Reduced fuel availability will only moderately diminish projected near-term increases in climate-driven forest fire area in the Western US, according to a macroscale climate–fire model.
... Catastrophic wildfires are becoming more frequent and severe in many parts of the world and are associated with unprecedented impacts (Bowman et al., 2017;Dutta et al., 2016;Filkov et al., 2020;Flannigan et al., 2013;Nauslar et al., 2018;Tran et al., 2020). This is particularly true in Australia and North America, as demonstrated by recent (2019/2020) catastrophic wildfires in southeast Australia and California (Bowman et al., 2017;CAL FIRE, 2020;Filkov et al., 2020). ...
Article
The rapid increase in severe wildfires in many parts of the world, especially in temperate systems, requires urgent attention to reduce fires’ catastrophic impacts on human lives, livelihoods, health and economy. Of particular concern is southeast Australia, which harbours one of the most flammable vegetation types on Earth. While previous studies suggest climate and European activities drove changes in southeast Australian fire regimes in the last 200 years, no study has quantitatively tested the relative roles of these drivers. Here, we use a Generalized Linear Modelling to identify the major driver(s) of fire regime change in the southeast Australian mainland during and prior to European colonization. We use multiple charcoal and pollen records across the region and quantitatively compare fire history to records of climate and vegetation change. Results show low levels of biomass burned before colonization, when landscapes where under Indigenous management, even under variable climates. Biomass burned increased markedly due to vegetation/land-use change after colonization and a major decline in regional precipitation about 100 years later. We conclude that Indigenous-maintained open vegetation minimized the amount of biomass burned prior to colonization, while European-suppression of Indigenous land management has amplified biomass accumulation and fuel connectivity in southeast Australian forests since colonization. While climate change remains a major challenge for fire mitigation, implementation of a management approach similar to the pre-colonial period is suggested to ameliorate the risk of future catastrophic fires in the region.
... Due to global warming, as well as the difference in insolation of the hemispheres (Berger 1988), the polar regions of both hemispheres warm faster in spring than other areas of low latitudes (IPCC 2013(IPCC , 2014. In this regard, the importance of monitoring and forecasting forest fires in the taiga of Canada and Siberia during April-May (Flannigan et al. 2013;Ponomarev et al. 2016), and the forests of southern Australia from November-December (Virgilio et al. 2019) is increasing. The modeling of the stratospheric-tropospheric relationships suggests that in a significant number of cases the long-term localization of high altitude fire events is the result of stratospheric-tropospheric impacts (Krasouski et al. 2014). ...
Chapter
Sustainable Land Management (SLM) is one of the transformative pillars for agricultural development and environment conservation for food, forage, fuel and fibre security. It aims at the tripartite benefits of high yields, environment protection and income security. The success of SLM is a function of adopting appropriate nutrients and water management practices. Several land management practices have been practiced by smallholder farming systems in great lakes region in Africa. However, there is still limited understanding of the level of acceptability of the various technologies in mitigating soil water shortage and nutrient depletion. This paper evaluates the SLM concept with focus on assessing sustainability in the use of various soil water and nutrient management technologies and practices. Nutrient management measures assessed included a range of common inputs and practices in tropical farming systems. Soil water conservation technologies assessed included the physical, biological and agronomic measures. Analysis conducted suggest that few land users can afford to adopt most of the technologies that define a full package for realization of the pillars of SLM. The integrated use of technologies is an appropriate approach to respond to alarming challenge of land degradation. The inclusion of social-cultural and economic factors in the use of these soil, water and nutrient technologies is fundamental for increasing the adoption rate in communities. Policies should target integrated technologies that are community and/or people centered in SLM if the goal of enhanced agricultural productivity, environment conservation and income is to be realized in the great lakes region of Africa.
... Due to global warming, as well as the difference in insolation of the hemispheres (Berger 1988), the polar regions of both hemispheres warm faster in spring than other areas of low latitudes (IPCC 2013(IPCC , 2014. In this regard, the importance of monitoring and forecasting forest fires in the taiga of Canada and Siberia during April-May (Flannigan et al. 2013;Ponomarev et al. 2016), and the forests of southern Australia from November-December (Virgilio et al. 2019) is increasing. The modeling of the stratospheric-tropospheric relationships suggests that in a significant number of cases the long-term localization of high altitude fire events is the result of stratospheric-tropospheric impacts (Krasouski et al. 2014). ...
Chapter
Fire is a disturbance factor in the gallery forests and palm swamps of the Orinoco region of Colombia, due to the recurrent burnings of the surrounding savannas. Since fire is used as a cost-effective land-management tool, savannas are usually burned once a year in the dry season. This chapter evaluates how fire frequencies impact the regeneration of M. flexuosa, by comparing seedling and sapling density in palm swamps with different time since last burn in the department of Vichada, Orinoco region of Colombia. It attempts to give recommendations for fire management in the savannas of the region.
... Muchas veces, el análisis ex post, evidencia un problema de enfoque, casi exclusivamente ligado a la existencia de plantaciones o bosques, sin integrar adecuadamente la composición del paisaje, la infraestructura y la peligrosa aproximación de zonas habitadas (Galilea, 2019;Dombeck, et al., 2004;Chaz, 2013;Flannigan, et al., 2012y CFA, 2012, Fernández Aragón, I. et al. 2021. Tras la experiencia, se comienza a actuar tratando de establecer distancias más adecuadas, sin llegar todavía a establecer indicaciones o protocolos hacia las acciones de mitigación y protección de las propias viviendas, incluyendo el despeje de áreas cercanas, materialidades y otros temas específicos que articulen y compartan responsabilidades también hacia los habitantes que tendrían que organizarse si viven en estas áreas. ...
Article
Full-text available
Given the frequency and intensity of climatic events, it is essential to connect the territorial risk planning and management instruments with requirements to buildings located in risk areas. If buildings in rural and peri- urban areas with low technical specifications at wildland urban interface, fire safety are pre-emptively inspected, it is possible to plan preventive measures, under legally applicable standards. International experience indicates that houses can be safer, for example, establishing protection areas (30-60 meters) and acting on the density and spacing of combustible vegetation. In this sense, this study addresses protection considering the relationship of the immediate environment with the characteristics of the building under threat. For this purpose, the Chilean, American, European and Australian regulations are reviewed with respect to the guarantee of fire performance of buildings and their immediate environment, extracting quality standards and recommendations, considering the needs and regulations house in and house out. . Specific security measures such as fire resistance of structural and non-structural elements, non-combustible material, non-flammability, non-toxicity and opacity of fumes; increased massiveness and coverage with non- combustible elements; limitations of use of plastic materials and others that provide fuel load are passive protection aspects to be included in evaluation.
... 27 28 Recent global studies demonstrate that annual burned area has decreased in recent decades 6 , while 29 extreme wildfire events are becoming more frequent and intense 6,7,8 . Drivers of these trends include 30 fragmentation of fuel landscapes with land use change, accumulation of flammable vegetation after 31 suppression of human fire use, and lengthening fire weather windows due to climate change 9,10 . In 32 this context we need to better understand the conditions under which the loss of livelihood-oriented 33 fire use can lead to wildfires. ...
Preprint
Full-text available
Controlled fire use by hunter-gatherers and smallholder agriculturalists and pastoralists shapes ecologies and enhances livelihoods worldwide. Yet, at the global scale, we know little about how these practices influence human wellbeing, ecologies, and wildfire risk. As a basis for global syntheses, we collated information from the literature about fire practices in 587 case study locations spanning the globe. Here, we assess the coverage and completeness of this data. Limited quantitative data, particularly, presents a challenge for improved modelling of anthropogenic influences on fire regimes. We also analyse global trends in fire practices from these studies, finding evidence that subsistence-oriented fire practices have declined in recent decades, while market-oriented fire practices have increased. The case studies point to important drivers of these changes, especially economic pressures, and state governance. We discuss the implications of these findings for fire policy, and future research.
... It has been proven that land use/land cover change (LUCC) is one of the crucial factors profoundly affecting the climate at both a regional and a global scale, such as surface temperature [2], carbon emissions [3] extreme wheather [4]. Simultaneously, human policies can significantly affect land change, such as urban planning, land management, afforestation, deforestation, and agricultural expansion [5][6][7][8][9]. To address the challenges of climate change and create a more liveable future, countries worldwide have formulated sustainable goals and plans that can be achieved through implementable policies. ...
Article
Scenario-based land use/land cover change (LUCC) simulation can explore different possibilities in the future for decision-making on city development. However, the current LUCC research in urban-rural areas still lacks support for local climate change research due to unmatched scenario settings and simplified land coverage classification. We thus adopt the local climate zone (LCZ) scheme, which includes more detailed 18 land types, to explore future LUCC in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) under the latest Intergovernmental Panel on Climate Change (IPCC) scenario, the shared socioeconomic pathways (SSPs), with different policy constraints. First, we produce a 100-m spatial resolution LCZ map of the GBA in 2020, which achieves an accuracy with Kappa = 0.876. Then, we carry out an LCZ simulation by adopting the Global Change Analysis Model (GCAM) and Future Land Use Simulation Model (FLUS) from 2020 to 2100 under the SSPs. The results show that LCZ projections appropriately reflect different land responses under different SPPs and the contrastive LCZ spatial changes among different cities even under the same scenario. Ecological protection is a crucial goal in the development plan of the Chinese government. Thus, we add the ecological control lines to protect ecological land under SSPs. This protection is pronouncedly reflected in ecological land within built-up areas in central cities and ecological land around urban areas in fringe cities. This study is the first test of LCZ projection under SSPs. The study findings could serve as an application potential for urban planning, urban climate and mega-city studies globally.
... Extended fire seasons and droughts associated with climate warming 30,31 may counteract the natural fire extinction in autumn and instead increase the chances of fires entering a smouldering phase. An important driver modulating Article the emergence of large overwintering fires may therefore be warm and extreme summers that facilitate long and large fire seasons 31,32 . Within our time series, we found no evidence that winter and spring meteorology or snowmelt timing influence the survival of large overwintering fires (Extended Data Tables 1, 2). ...
Article
Full-text available
Forest fires are usually viewed within the context of a single fire season, in which weather conditions and fuel supply can combine to create conditions favourable for fire ignition—usually by lightning or human activity—and spread1–3. But some fires exhibit ‘overwintering’ behaviour, in which they smoulder through the non-fire season and flare up in the subsequent spring4,5. In boreal (northern) forests, deep organic soils favourable for smouldering⁶, along with accelerated climate warming⁷, may present unusually favourable conditions for overwintering. However, the extent of overwintering in boreal forests and the underlying factors influencing this behaviour remain unclear. Here we show that overwintering fires in boreal forests are associated with hot summers generating large fire years and deep burning into organic soils, conditions that have become more frequent in our study areas in recent decades. Our results are based on an algorithm with which we detect overwintering fires in Alaska, USA, and the Northwest Territories, Canada, using field and remote sensing datasets. Between 2002 and 2018, overwintering fires were responsible for 0.8 per cent of the total burned area; however, in one year this amounted to 38 per cent. The spatiotemporal predictability of overwintering fires could be used by fire management agencies to facilitate early detection, which may result in reduced carbon emissions and firefighting costs.
... The strong association between anomalous fire weather and extreme fire behaviour suggests that anthropogenic climate change will impact future fire regimes 23,104 , including in those regions already vulnerable to fire disasters, such as the western USA, Mediterranean and southern Australia 23 . A global analysis using 17 global climate models, and highlighted regionally in TAble 1, suggests there will be a large increase in the occurrence of extreme fire weather for much of the globe, with some of the largest increases the Mediterranean and the Amazon 105 . ...
Article
Full-text available
Vegetation fires are an essential component of the Earth system but can also cause substantial economic losses, severe air pollution, human mortality and environmental damage. Contemporary fire regimes are increasingly impacted by human activities and climate change, but, owing to the complex fire–human–climate interactions and incomplete historical or long-term datasets, it is difficult to detect and project fire-regime trajectories. In this Review, we describe recent global and regional trends in fire activity and examine projections for fire regimes in the near future. Although there are large uncertainties, it is likely that the economic and environmental impacts of vegetation fires will worsen as a result of anthropogenic climate change. These effects will be particularly prominent in flammable forests in populated temperate zones, the sparsely inhabited flammable boreal zone and fire-sensitive tropical rainforests, and will contribute to greenhouse gas emissions. The impacts of increased fire activity can be mitigated through effective stewardship of fire regimes, which should be achieved through evidence-based fire management that incorporates indigenous and local knowledge, combined with planning and design of natural and urban landscapes. Increasing transdisciplinary research is needed to fully understand how Anthropocene fire regimes are changing and how humans must adapt.
... It is estimated that about 3.8 million ha of peatland in Russian Federation territory (mainly in the European part) have been drained (Päivanen and Paavilainen, 1996). A forecasted increase in the intensity of fires in the current century in Europe (Flannigan et al., 2013) will potentially affect peatlands hydrology and carbon balance. Moreover, the peatlands can often be the only source of water for animals in the face of climate change and the growing hydrological crisis. ...
Article
This paper presents the results of multiproxy research (pollen, charcoal, plant macrofossil and testate amoebae) on the biogenic deposits core from Gorodetsky Moch, an ombrotrophic peatland in western Russia (Western Dvina Lakeland). We reconstructed the impact of disturbance on peatland development in the last 300 years by using chronology of the records based on ¹⁴ C and ²¹⁰ Pb data set. The multiproxy reconstruction was compared with changes in the land cover using historical maps and Corona images, which provides a unique spatial analysis of past ecological and land-use changes. We aimed to determine the effect of local disturbances (drainage) and land-use changes (landscape openness) on the development of the peatland during the last 300 years. Our study suggests that human activity had a crucial impact on the development of the peatland in the last centuries. The analysis of testate amoebae and plant macrofossils revealed a clear disturbed layer in the second half of the 20th century CE. Most probably, the drainage of the peatland triggered changes in the community of testate amoebae and plants, thereby causing a functional shift in Sphagnum peatland ecosystem. The hydrological stress and vegetation composition shift led to the collapse of mixotrophic testate amoebae. However, the peatland showed strong resilience and recovered toward the end of the 20th century CE and the beginning of the 21st century CE, despite the lower water table. Our study shows an example of the peatland ecosystem that experienced a considerable stress but finally sustained the former function.
... Nonetheless, burned area has increased in forested regions with high BC production rates per unit area, and thus global rates of BC production by landscape fires showed no trend in the past two decades 16 . According to fire models, global burned area is likely to increase in the coming centuries, with this increase concentrated in forests and in regions where the human capacity to suppress fire fails to keep pace with increasing ignition frequency [73][74][75][76] . Through their control on the rates of BC input to soils and waters, these historical and future changes in global fire incidence may have cascading impacts on terrestrial BC stocks, the riverine export of BC and the placement of BC into oceanic storage. ...
Article
Full-text available
Black carbon (BC) is a recalcitrant form of organic carbon (OC) produced by landscape fires. BC is an important component of the global carbon cycle because, compared to unburned biogenic OC, it is selectively conserved in terrestrial and oceanic pools. Here we show that the dissolved BC (DBC) content of dissolved OC (DOC) is twice greater in major (sub) tropical and high-latitude rivers than in major temperate rivers, with further significant differences between biomes. We estimate that rivers export 18 ± 4 Tg DBC year −1 globally and that, including particulate BC fluxes, total riverine export amounts to 43 ± 15 Tg BC year −1 (12 ± 5% of the OC flux). While rivers export~1% of the OC sequestered by terrestrial vegetation, our estimates suggest that 34 ± 26% of the BC produced by landscape fires has an oceanic fate. Biogeochemical models require modification to account for the unique dynamics of BC and to predict the response of recalcitrant OC export to changing environmental conditions.
Article
Full-text available
Fire affects many critical ecological processes, including pollination, and effects of climate change on fire regimes may have profound consequences that are difficult to predict. Considerable work has examined effects of fire on pollinator diversity, but relatively few studies have examined these effects on interaction networks including those of pollinators other than bees. We examined the effects of a severe wildfire on hoverfly pollinators in a Mediterranean island system. Using data collected over 3 consecutive years at burnt and unburnt sites, we documented differences in species diversity, abundance, and functional traits, as well as hoverfly interactions with flowering plants. Hoverfly abundance and species richness peaked during the first post‐fire flowering season (year 1), which coincided with the presence of many opportunistic species. Also in year 1, hoverfly pollination networks were larger, less specialized, more nested, and less modular at burnt (vs. unburnt) sites; furthermore, these networks exhibited higher phylogenetic host‐plant diversity. These effects declined over the next 2 years, with burnt and unburnt sites converging in similarity to hoverfly communities and interaction networks. While data obtained over 3 years provide a clear timeline of initial post‐fire recovery, we emphasize the importance of longer‐term monitoring for understanding the responses of natural communities to wildfires, which are projected to become more frequent and more destructive in the future.
Article
Full-text available
Current lightning predictions are uncertain because they rely on empirical diagnostic relationships and often use coarse‐scale climate scenario simulations in which deep convection is parameterized. Previous studies demonstrated that simulations with convection‐permitting resolutions improve lightning predictions compared to coarser‐grid simulations using convection parameterizations for different geographical locations but not over the boreal zone. In this study, lightning simulations with the NASA Unified‐Weather Research and Forecasting model are evaluated over a domain including the Great Slave Lake in Canada, for six lightning seasons. The simulations are performed at convection‐parameterized (9 km) and convection‐permitting (3 km) resolution using the Goddard 4ICE and the Thompson microphysics schemes. Four lightning indices are evaluated against observations from the Canadian Lightning Detection Network, in terms of spatiotemporal frequency distribution, spatial pattern, daily climatology, and an event‐based overall skill assessment. The Thompson scheme is, regardless of the spatial resolution, superior to the Goddard 4ICE scheme in predicting daily climatology but worse in predicting the spatial patterns of lightning occurrence. Results indicate that lightning estimation benefits from modeling at convection‐permitting resolution, in particular for the ice‐based lightning indices. In contrast, the product of convective available potential energy and precipitation rate proved to be the most robust index that was largely invariant to varying spatial resolution. Finally, this study reveals issues of the models to reproduce the observed spatial pattern of lightning well, which might be related to an insufficient representation of land surface heterogeneity, including peatlands, in the study area.
Article
Building more homes and amenities in the wildland-urban interface ( wui ) is not a sustainable practice as it is associated with a greater risk of wildfire, social vulnerability, and ecological damage. Yet, the issue of whether or how to regulate the expansion of the wui remains contentious and largely unresolved in understanding sustainable development. There are fewer studies that explore how wildfire risks are compounded by social vulnerability of people who reside in the fire prone wui . Additionally, much of the extant research is focused on the national or regional level management of ecosystems and forest fires, with a clear lack of focus on local level dynamics. To fill these gaps, our analysis outlines the preliminary steps to identify social vulnerability, ecological damage, and wildfire risk in the wui fire hazard zones of the highest severity type. Utilizing gis mapping, wildfire risk, and census data on social vulnerability, our analysis reveals patterns of the wui expansion in the San Francisco Bay Area from 1990 to 2010 and provides policy recommendations from a sustainable development perspective to address social vulnerability, wildfire risk, and ecological concerns over the wui .
Article
Full-text available
Wildfires significantly impact air quality and climate, including through the production of aerosols that can nucleate cloud droplets and participate in aqueous‐phase reactions. Cloud water was collected during the summer months (June–September) of 2010–2017 at Whiteface Mountain, New York and examined for biomass burning influence. Cloud water samples were classified by their smoke influence based on backward air mass trajectories and satellite‐detected smoke. A total of 1,338 cloud water samples collected over 485 days were classified by their probability of smoke influence, with 49% of these days categorized as having moderate to high probability of smoke influence. Carbon monoxide and ozone levels were enhanced during smoke influenced days at the summit of Whiteface Mountain. Smoke‐influenced cloud water samples were characterized by enhanced concentrations of potassium, sulfate, ammonium, and total organic carbon, compared to samples lacking identified influence. Five cloud water samples were examined further for the presence of dissolved organic compounds, insoluble particles, and light‐absorbing components. The five selected cloud water samples contained the biomass burning tracer levoglucosan at 0.02–0.09 μM. Samples influenced by air masses that remained aloft, above the boundary layer during transport, had lower insoluble particle concentrations, larger insoluble particle diameters, and larger oxalate:sulfate ratios, suggesting cloud processing had occurred. These findings highlight the influence that local and long‐range transported smoke have on cloud water composition.
Article
Full-text available
Recent wildfires across western North America have burned with uncharacteristically high severity, representing a substantial departure from natural fire regimes. In mixed‐conifer and pine–oak ecosystems of the southern Cascade Range, widespread shifts in stand structure and composition have led to a diversity of post‐wildfire vegetation responses. When recent wildfire “footprints” reburn in subsequent fires, their recovery pathways are complex. In order to understand the effects of overlapping mixed‐severity fires, we quantified changes in overstory and midstory structure and species composition for time periods prior to and following two large overlapping wildfires in the southern Cascades: the 2000 Storrie and 2012 Chips Fires. Plots were stratified into 16 severity combinations (unburned, low, moderate, and high in the Storrie Fire combined with the same four categories in the Chips Fire: e.g., moderate Storrie/high Chips) across the 9000‐ha overlapping burned area. Following the two fires, tree quadratic mean diameter and stand density declined for most species, but changes were species‐specific. Compared with preburn values, importance values for fire‐sensitive white fir (Abies concolor) were reduced by 66%, while resprouting fire‐resilient California black oak (Quercus kelloggii) importance values increased by 37% in severity combinations that included at least one high‐severity fire. Greatest shifts were documented in sites that burned twice at high severity, where resulting vegetation was dominated by oak sprout clumps and resprouting and fire‐stimulated montane chaparral species, while unburned and low‐severity strata retained a substantial component of Douglas‐fir (Pseudotsuga menziesii) and white fir. Results suggest that repeated moderate‐ and high‐severity fires can result in ecosystem state shifting toward fire‐resilient oak‐shrub communities in this fire‐prone landscape. Managers seeking greater landscape resilience can implement treatments such as thinning and prescribed burning, while taking advantage of fire‐created patches such as these in areas where the likelihood of a hotter and drier future makes the reestablishment of continuous forest cover unrealistic.
Article
Large‐scale, high‐severity wildfires are increasingly frequent across the western United States. Fire severity affects the amount of vegetation removed and helps dictate what, where, and how many plants regenerate postfire, potentially altering the available habitat and nutritional landscape for wildlife. To evaluate the effects of fire severity on summer nutritional resources for elk (Cervus canadensis), we collected field data and remotely sensed information in Years 2 and 3 after a large‐scale wildfire to compare forage quality and quantity across forest types and fire severities within the summer range of one elk population in west‐central Montana. To understand the landscape‐level effects of fire severity on nutritional resources, we developed predictive forage quality and quantity models. We used these models to predict nutritional resources across the landscape for four landscape scenarios representing different fire severity patterns (i.e., an unburned landscape, a landscape burned only at low severity, a landscape burned only at high severity, and the observed landscape burned at mixed severity). Shortly after the wildfire, summer forage quality and herbaceous forage quantity increased in both burned mesic and dry mixed‐conifer forests regardless of fire severity. Summer shrub forage quantity was greater in unburned mesic and dry forests, and there was no difference between fire severities in dry forests. Low‐severity burned mesic forests had significantly greater shrub forage quantity compared with high‐severity burned mesic forests. The three predicted burned landscape scenarios had the highest percentage of the summer range with adequate forage quality, which increased throughout the summer. By contrast, the predicted unburned landscape had the lowest percentage of summer range with adequate forage quality, which decreased throughout the summer. Wildfire extended the duration in which elk can access high‐quality forage in the summer in Years 2 and 3 postfire. Therefore, shortly after a large‐scale wildfire, elk may be better able to meet their nutritional requirements, which may positively impact elk body condition, reproductive performance, and survival.
Article
Abstract Low‐likelihood weather events can cause dramatic impacts, especially when they are unprecedented. In 2020, amongst other high‐impact weather events, UK floods caused more than £300 million damage, prolonged heat over Siberia led to infrastructure failure and permafrost thawing, while wildfires ravaged California. Such rare phenomena cannot be studied well from historical records or reanalysis data. One way to improve our awareness is to exploit ensemble prediction systems, which represent large samples of simulated weather events. This ‘UNSEEN’ method has been successfully applied in several scientific studies, but uptake is hindered by large data and processing requirements, and by uncertainty regarding the credibility of the simulations. Here, we provide a protocol to apply and ensure credibility of UNSEEN for studying low‐likelihood high‐impact weather events globally, including an open workflow based on Copernicus Climate Change Services (C3S) seasonal predictions. Demonstrating the workflow using European Centre for Medium‐Range Weather Forecasts (ECMWF) SEAS5, we find that the 2020 March–May Siberian heatwave was predicted by one of the ensemble members; and that the record‐shattering August 2020 California‐Mexico temperatures were part of a strong increasing trend. However, each of the case studies exposes challenges with respect to the credibility of UNSEEN and the sensitivity of the outcomes to user decisions. We conclude that UNSEEN can provide new insights about low‐likelihood weather events when the decisions are transparent, and the challenges and sensitivities are acknowledged. Anticipating plausible low‐likelihood extreme events and uncovering unforeseen hazards under a changing climate warrants further research at the science‐policy interface to manage high impacts.
Article
Full-text available
Recent wildfire outbreaks around the world have prompted concern that climate change is increasing fire incidence, threatening human livelihood and biodiversity, and perpetuating climate change. Here, we review current understanding of the impacts of climate change on fire weather (weather conditions conducive to the ignition and spread of wildfires) and the consequences for regional fire activity as mediated by a range of other bioclimatic factors (including vegetation biogeography, productivity and lightning) and human factors (including ignition, suppression, and land use). Through supplemental analyses, we present a stocktake of regional trends in fire weather and burned area (BA) during recent decades, and we examine how fire activity relates to its bioclimatic and human drivers. Fire weather controls the annual timing of fires in most world regions and also drives inter‐annual variability in BA in the Mediterranean, the Pacific US and high latitude forests. Increases in the frequency and extremity of fire weather have been globally pervasive due to climate change during 1979–2019, meaning that landscapes are primed to burn more frequently. Correspondingly, increases in BA of ∼50% or higher have been seen in some extratropical forest ecoregions including in the Pacific US and high‐latitude forests during 2001–2019, though interannual variability remains large in these regions. Nonetheless, other bioclimatic and human factors can override the relationship between BA and fire weather. For example, BA in savannahs relates more strongly to patterns of fuel production or to the fragmentation of naturally fire‐prone landscapes by agriculture. Similarly, BA trends in tropical forests relate more strongly to deforestation rates and forest degradation than to changing fire weather. Overall, BA has reduced by 27% globally in the past two decades, due in large part to a decline in BA in African savannahs. According to climate models, the prevalence and extremity of fire weather has already emerged beyond its pre‐industrial variability in the Mediterranean due to climate change, and emergence will become increasingly widespread at additional levels of warming. Moreover, several of the major wildfires experienced in recent years, including the Australian bushfires of 2019/2020, have occurred amidst fire weather conditions that were considerably more likely due to climate change. Current fire models incompletely reproduce the observed spatial patterns of BA based on their existing representations of the relationships between fire and its bioclimatic and human controls, and historical trends in BA also vary considerably across models. Advances in the observation of fire and understanding of its controlling factors are supporting the addition or optimization of a range of processes in models. Overall, climate change is exerting a pervasive upwards pressure on fire globally by increasing the frequency and intensity of fire weather, and this upwards pressure will escalate with each increment of global warming. Improvements to fire models and a better understanding of the interactions between climate, climate extremes, humans and fire are required to predict future fire activity and to mitigate against its consequences.
Article
Full-text available
Plain Language Summary Wildfire smoke is a major source of air pollution that affects public health and natural areas, but the amounts of vegetation that go up in smoke and the emitted amounts of smoke are not well known, due to a lack of direct measurements. The accuracy of models used to predict smoke impacts on public health in affected communities is significantly impacted by their reliance on uncertain emissions estimates. In this study, a new instrument, the University of Colorado Airborne Solar Occultation Flux (CU AirSOF), measured the amount of carbon monoxide (CO) produced by the destructive fires in northern California during October 2017. These are the first airborne emission measurements on the scale of a large wildfire. The measured CO emissions from the fires fall within the large range among satellite‐based emission estimates, reducing the uncertainty in fire emissions. Air quality impacts in the form of ozone (O3) and fine particulate matter (PM2.5) range from insignificant to very severe, in direct relationship to the uncertain satellite‐based emission estimates.
Article
Background: Extreme weather events are intensifying with climate change, offering opportunities to raise the public urgency of this issue. The media’s role in communicating this connection is crucial. Analysis: This article analyzes media coverage of wildfires over a nine-year period in British Columbia focusing on how they are linked to climate change, in particular, during the 2017 and 2018 record-breaking fire seasons. Conclusion and implications: In media coverage in British Columbia, there is a marked absence of a link between climate change and wildfires and a tendency for connections to be tokenistic, decontextualized, and normalizing. More provocative narratives developed by various public figures that locate wildfires within broader narratives of climate crisis offer more compelling accounts. Contexte : À cause du changement climatique, les événements climatiques extrêmes sont en train de devenir plus intenses. Dans les circonstances, il devient pertinent de soulever l’urgence publique de cet enjeu, et les médias pourraient jouer un rôle crucial pour le communiquer. Analyse : Cet article analyse la couverture médiatique de feux de forêt sur une période de neuf ans en Colombie-Britannique, particulièrement durant les saisons des feux de 2017 et 2018 qui ont battu tous les records. L’article met l’accent sur comment ces incendies sont reliés au changement climatique. Conclusions et implications : Dans la couverture médiatique en Colombie-Britannique, on néglige de montrer les liens qui existent entre le changement climatique et les feux de forêt. Toute connexion établie tend à être superficielle, décontextualisée et normalisée. En revanche, diverses personnalités publiques ont incorporé les feux de forêt dans des narrations englobant l’idée de crise climatique, offrant ainsi une perspective plus intéressante, voire provocatrice.
Article
Extreme weather events are intensifying with climate change, offering opportunities to raise the public urgency of this issue. The media's role in communicating this connection is crucial. This article analyzes media coverage of wildfires over a nine-year period in British Columbia focusing on how they are linked to climate change, in particular, during the 2017 and 2018 record-breaking fire seasons. In media coverage in British Columbia, there is a marked absence of al ink between climate change and wildfires and a tendency for connections to be tokenistic, decontextualized, and normalizing. More provocative narratives developed by various public figures that locate wildfires within broader narratives of climate crisis offer more compelling accounts.
Article
Full-text available
Forested, mountain landscapes in the Pacific Northwest (PNW) are changing at an unprecedented rate, largely due to shifts in the regional climate regime. Documented climate warming trends across the PNW include increasing wildfire frequency and severity and an increasingly ephemeral snowpack, especially at moderate elevations. We analyzed 24 high severity wildfires across four distinct PNW mountainous subregions, examining snow‐vegetation relationships for two years pre‐fire and four years post‐fire. To assess the importance of snow cover for revegetation compared to other climatic, topographic, and burn severity‐related variables, binary regression tree models were constructed for the dominant pre‐fire conifer species within each of the four PNW subregions. Summer precipitation consistently appeared as the most important variable driving post‐fire revegetation across all four subregions. Snow cover variables (snow cover frequency and snow disappearance date), along with elevation, were shown to be secondary but significantly influential explanatory variables for revegetation in the Oregon and Washington Cascades. Revegetation was also analyzed using a time series of linear regressions across 200‐m elevation bands by measuring correlations between winter snow cover and summer vegetation greenness. Results showed strong positive post‐fire correlations at moderate elevations in the western Montana Rockies and at the lowest elevation band in the Idaho Rockies. Considering trends of increasing wildfire activity, lower snowpacks, and earlier snow disappearance dates across the PNW, forests will likely experience more frequent drought conditions that will impact post‐wildfire vegetation regrowth.
Article
Full-text available
Wildland fires involve complicated processes that are challenging to represent in chemical transport models. Recent airborne measurements reveal remarkable chemical tomography in fresh wildland fire plumes, which remain yet to be fully explored using models. Here, we present a high‐resolution large eddy simulation model coupled to chemistry to study the chemical evolution in fresh wildland fire plume. The model is configured for a large fire heavily sampled during the Fire Influence on Regional to Global Environments and Air Quality field campaign, and a variety of airborne measurements are used to evaluate the chemical heterogeneity revealed by the model. We show that the model captures the observed cross‐transect variations of a number of compounds quite well, including ozone (O3), nitrous acid (HONO), and peroxyacetyl nitrate. The combined observational and modeling results suggest that the top and edges of fresh plume drive the photochemistry, while dark chemistry is also present but in the lower part of the plume. The model spatial resolution is shown to be very important as it may shift the chemical regime, leading to biases in O3 and NOx chemistry. Based on findings in this work, we speculate that the impact of small fires on air quality may be largely underestimated in models with coarse spatial resolutions.
Article
Full-text available
Comprender la evolución de las causas de los incendios permite realizar un trabajo objetivo de prevención. Esta investigación analiza la causalidad de los incendios forestales en Pinar del Río, Cuba (1975-2018). Los análisis se realizaron considerando sub-periodos, meses del año y vegetación afectada. En el periodo ocurrieron 2896 incendios y se quemaron 51 217.75 hectáreas. Los incendios originados por causas antropogénicas, principalmente las negligencias, mostraron una tendencia al aumento en el tiempo, contrario a lo ocurrido para el caso de los rayos. Esta evolución determinó que la época de incendios cambiara de marzo a junio en el sub-periodo 1975-1985, y pasara a presentarse de marzo a mayo en el sub-periodo 2008-2018. No obstante, la época donde más incendios ocurren por cada causa de forma individual no cambió durante los 44 años analizados. Estos resultados permitirán perfeccionar el trabajo de prevención de incendios forestales.
Article
Natural disturbances like drought and wildfires are expected to increase in prevalence, so understanding how organisms are affected is a key goal for conservationists and biologists alike. While many studies have illustrated long-term effects of perturbations on survival and reproduction, little is known of short-term effects to physiology and sexual signal expression. Ornamental traits have been proposed as reliable indicators of environmental health, yet studies are lacking in the context of natural disturbances. Here we present short-term (7–65 days) responses of male red-backed fairywrens Malurus melanocephalus to wildfire near the onset of the typical breeding season. Young males of this species are characterized by plastic expression of sexual plumage phenotypes depending on circulating testosterone and body condition. Using two populations with fairywren captures before and after separate wildfires we illustrate that wildfire suppressed molt into ornamented plumage. Neither baseline plasma corticosterone or furcular fat stores were affected by fire. However, fire seemed to interfere with the termporal increase in plasma testosterone during the pre-breeding season, leading to a lower proportion of males molting into ornamented plumage. Collectively, these findings suggest that wildfires inhibit or greatly delay acquisition of ornamentation in males through enduring suppression of testosterone circulation.
Article
No single factor produces wildfires; rather, they occur when fire thresholds (ignitions, fuels, and drought) are crossed. Anomalous weather events may lower these thresholds and thereby enhance the likelihood and spread of wildfires. Climate change increases the frequency with which some of these thresholds are crossed, extending the duration of the fire season and increasing the frequency of dry years. However, climate‐related factors do not explain all of the complexity of global fire‐regime changes, as altered ignition patterns (eg human behavior) and fuel structures (eg land‐use changes, fire suppression, drought‐induced dieback, fragmentation) are extremely important. When the thresholds are crossed, the size of a fire will largely depend on the duration of the fire weather and the extent of the available area with continuous fuels in the landscape.
Article
Full-text available
Aim Megafires are increasing in intensity and frequency globally. The impacts of megafires on biodiversity can be severe, so conservation managers must be able to respond rapidly to quantify their impacts, initiate recovery efforts and consider conservation options within and beyond the burned extent. We outline a framework that can be used to guide conservation responses to megafires, using the 1.5 million hectare 2019/2020 megafires in Victoria, Australia, as a case study. Location Victoria, Australia. Methods Our framework uses a suite of decision support tools, including species attribute databases, ~4,200 species distribution models and a spatially explicit conservation action planning tool to quantify the potential effects of megafires on biodiversity, and identify species‐specific and landscape‐scale conservation actions that can assist recovery. Results Our approach identified 346 species in Victoria that had >40% of their modelled habitat affected by the megafire, including 45 threatened species, and 102 species with >40% of their modelled habitat affected by high severity fire. We then identified 21 candidate recovery actions that are expected to assist the recovery of biodiversity. For relevant landscape‐scale actions, we identified locations within and adjacent to the megafire extent that are expected to deliver cost‐effective conservation gains. Main conclusion The 2019/2020 megafires in south‐eastern Australia affected the habitat of many species and plant communities. Our framework identified a range of single‐species (e.g., supplementary feeding, translocation) and landscape‐scale actions (e.g., protection of refuges, invasive species management) that can help biodiversity recover from megafires. Conservation managers will be increasingly required to rapidly identify conservation actions that can help species recover from megafires, especially under a changing climate. Our approach brings together commonly used datasets (e.g., species distribution maps, trait databases, fire severity mapping) to help guide conservation responses and can be used to help biodiversity recover from future megafires across the world.
Article
Full-text available
Major wildfires starting in the summer of 2020 along the west coast of the United States made PM2.5 concentrations in this region rank among the highest in the world. Washington was impacted both by active wildfires in the state and aged wood smoke transported from fires in Oregon and California. This study aims to estimate the magnitude and disproportionate spatial impacts of increased PM2.5 concentrations attributable to these wildfires on population health. Daily PM2.5 concentrations for each county before and during the 2020 Washington wildfire episode (September 7–19) were obtained from regulatory air monitors. Utilizing previously established concentration‐response function (CRF) of PM2.5 (CRF of total PM2.5) and odds ratio (OR) of wildfire smoke days (OR of wildfire smoke days) for mortality, we estimated excess mortality attributable to the increased PM2.5 concentrations in Washington. On average, daily PM2.5 concentrations increased 97.1 μg/m³ during the wildfire smoke episode. With CRF of total PM2.5, the 13‐day exposure to wildfire smoke was estimated to lead to 92.2 (95% CI: 0.0, 178.7) more all‐cause mortality cases; with OR of wildfire smoke days, 38.4 (95% CI: 0.0, 93.3) increased all‐cause mortality cases and 15.1 (95% CI: 0.0, 27.9) increased respiratory mortality cases were attributable to the wildfire smoke episode. The potential impact of avoiding elevated PM2.5 exposures during wildfire events significantly reduced the mortality burden. Because wildfire smoke episodes are likely to impact the Pacific Northwest in future years, continued preparedness and mitigations to reduce exposures to wildfire smoke are necessary to avoid excess health burden.
Article
Biodiversity faces many threats and these can interact to produce outcomes that may not be predicted by considering their effects in isolation. Habitat loss and fragmentation (hereafter 'fragmentation') and altered fire regimes are important threats to biodiversity, but their interactions have not been systematically evaluated across the globe. In this comprehensive synthesis, including 162 papers which provided 274 cases, we offer a framework for understanding how fire interacts with fragmentation. Fire and fragmentation interact in three main ways: (i) fire influences fragmentation (59% of 274 cases), where fire either destroys and fragments habitat or creates and connects habitat; (ii) fragmentation influences fire (25% of cases) where, after habitat is reduced in area and fragmented , fire in the landscape is subsequently altered because people suppress or ignite fires, or there is increased edge flammability or increased obstruction to fire spread; and (iii) where the two do not influence each other, but fire interacts with fragmentation to affect responses like species richness, abundance and extinction risk (16% of cases). Where fire and fragmentation do influence each other, feedback loops are possible that can lead to ecosystem conversion (e.g. forest to grassland). This is a well-documented threat in the tropics but with potential also to be important elsewhere. Fire interacts with fragmentation through scale-specific mechanisms: fire creates edges and drives edge effects; fire alters patch quality; and fire alters landscape-scale connectivity. We found only 12 cases in which studies reported the four essential strata for testing a full interaction, which were fragmented and unfragmented landscapes that both span contrasting fire histories, such as recently burnt and long unburnt vegetation. Simulation and empirical studies show that fire and fragmentation can interact synergistically, multiplicatively, antagonistically or additively. These cases highlight a key reason why understanding interactions is so important: when fire and fragmentation act together they can cause local extinctions, even when their separate effects are neutral. Whether fire-fragmentation interactions benefit or disadvantage species is often determined by the species' preferred successional stage. Adding fire to landscapes generally benefits early-successional plant and animal species, whereas it is detrimental to late-successional species. However, when fire interacts with fragmentation , the direction of effect of fire on a species could be reversed from the effect expected by successional preferences. Adding fire to fragmented landscapes can be detrimental for species that would normally co-exist with fire, because species may no longer be able to disperse to their preferred successional stage. Further, animals may be attracted to particular successional stages leading to unexpected responses to fragmentation, such as higher abundance in more isolated unburnt patches. Growing human populations and increasing resource consumption suggest that fragmentation trends will worsen over coming years. Combined with increasing alteration of fire regimes due to climate change and human-caused ignitions, interactions of fire with fragmentation are likely to become more common. Our new framework paves the way for developing a better understanding of how fire interacts with fragmentation, and for conserving biodiversity in the face of these emerging challenges.
Article
Full-text available
California has experienced more wildfires in recent years, resulting in huge economic losses and threatening human health. Clarifying the meteorological environments of wildfires is foundational to improving the understanding and prediction of wildfires and their impacts. Here, 1,535 California wildfires during 1984–2017 are systematically investigated. Based on two key meteorological factors—temperature and moisture anomalies—all wildfires are classified into four groups: hot-dry, hot-wet, cold-dry, cold-wet. Most (∼60%) wildfires occurred on hot-dry days. Compositing the meteorological environments of the four groups shows that persistent high pressure and strong northeasterly wind descending from inland favor hot-dry conditions for wildfires. Self-organizing map analysis lends confidence in the large-scale meteorological pattern dominating hot-dry wildfires in California. Meteorological anomalies also influence wildfire size through their magnitudes, with moisture anomaly explaining the largest fraction (∼69%) of variability in wildfire sizes. In addition, 12.2% of wildfires occurred on hot-wet days, which may be related with lightning flashes. More lightning tends to trigger wildfires, but the wet condition helps to suppress the wildfire sizes. Total burned area by wildfires has significantly increased by ∼3.6% per year, indicating a doubling of burned area in 2017 relative to 1984, mainly dominated by hot-dry wildfires in summer. Drying and warming in conjunction with strengthening of the high pressure in summer and fall have the potential to support more frequent and larger hot-dry wildfires in California during the past several decades.
Article
Full-text available
Hydroclimatic changes associated with global warming over the past 50 years have been documented widely, but physical landscape responses are poorly understood thus far. Detecting sedimentary and geomorphic signals of modern climate change presents challenges owing to short record lengths, difficulty resolving signals in stochastic natural systems, influences of land use and tectonic activity, long-lasting effects of individual extreme events, and variable connectivity in sediment-routing systems. We review existing literature to investigate the nature and extent of sedimentary and geomorphic responses to modern climate change, focusing on the western United States, a region with generally high relief and high sediment yield likely to be sensitive to climatic forcing. Based on fundamental geomorphic theory and empirical evidence from other regions, we anticipate climate-driven changes to slope stability, watershed sediment yields, fluvial morphology, and aeolian sediment mobilization in the western United States. We find evidence for recent climate-driven changes to slope stability and increased aeolian dune and dust activity, whereas changes in sediment yields and fluvial morphology have been linked more commonly to nonclimatic drivers thus far. Detecting effects of climate change will require better understanding how landscape response scales with disturbance, how lag times and hysteresis operate within sedimentary systems, and how to distinguish the relative influence and feedbacks of superimposed disturbances. The ability to constrain geomorphic and sedimentary response to rapidly progressing climate change has widespread implications for human health and safety, infrastructure, water security, economics, and ecosystem resilience.
Article
Full-text available
The recent bushfires (2019-2020) in New South Wales (NSW) Australia were catastrophic by claiming human and animal lives, affecting ecosystems, destroying infrastructure, and more. Recent studies have investigated relationships between hydroclimatic signals and past bushfires, and very recently, a few commentary papers claimed drought and fuel moisture content as the probable causes for the widespread 2019-2020 bushfires. Therefore, in this study, a novel work of encompassing a wide range of factors attributing to the recent bushfires is presented. Empirical evidence-based statistical methods are used to identify the hydroclimatic variables and geomorphic characteristics contributing to the 2019-2020 bushfires. The results highlight that ongoing drought, surface soil moisture (SSM), wind speed (WS10), relative humidity (RH), heat waves (HW), dead and live fuel moisture, and certain land cover types create favorable conditions for fire ignition and aid in fire propagation in different regions of the NSW state. The findings suggest that accounting for the above-identified variables in bushfire prediction and monitoring system are crucial in avoiding such catastrophes in the future. The overarching application of this study is developing robust and more versatile fire protection planning and management. Plain Language Summary Since the 2019-2020 Australian bushfires were catastrophic in terms of burnt area and severity, a detailed analysis of the primary causes is crucial. In this paper, several probable causes are tested statistically to establish their relationship with the burnt area. The results indicate that the ongoing drought, surface soil moisture, wind speed, relative humidity, heat waves, dead and live fuel moisture, and land cover with certain vegetation (particularly native eucalyptus and grazing land) are the primary causes of the widespread bushfire. These results are extremely critical in updating the current bushfire planning and management.
Article
Full-text available
Aim Many studies investigating the response of wildlife to disturbance focus predominantly on the effects of the disturbance alone but fail to account for the influence of ecosystem productivity in moderating the response of species and thus the resulting biodiversity patterns. We use Huston's dynamic equilibrium model (DEM) to explore the relationship between avian diversity and fire across the greater Rocky Mountain region of the western United States. This model provides the theoretical foundation to understand the distinct and interactive effects disturbance and productivity have on regulating species richness. Location We used avian monitoring data collected at 120 sites across Colorado, Idaho, Montana and Wyoming in the western United States from 2008 to 2016. Methods We used a Bayesian hierarchical multispecies occupancy model to predict species richness across fire and productivity gradients. Hierarchical models enable inference at the community and species level, accounting for imperfect detection, and providing a more accurate assessment of the ecological relationships. Results We found support of the hypotheses described by the DEM Avian species richness changed little across the fire severity gradient alone, though this relationship varies considerably when including the interaction of fire and ecosystem productivity. At lower latitudes, richness is greatest at intermediate levels of fire severity and productivity following the DEM. However, as latitude increases, the productivity at which richness is greatest also increases. Mean productivity increases with latitude across the study area, and we argue the changing regional levels of ecosystem productivity alters the relationships predicted by the DEM. Main conclusions Our results provide an important example of how relationships between richness and disturbance may be missed if viewed outside the context of other environmental factors, mainly ecosystem productivity. This highlights the importance of accounting for changing ecological context across broad spatial scales to ensure accurate assessments of disturbance–diversity relationships.
Article
Full-text available
Understanding tree physiological responses to fire is needed to accurately model post-fire carbon processes and inform management decisions. Given trees can die immediately or at extended time periods after fire, we combined two experiments to assess the short- (one-day) and long-term (21-months) fire effects on Pinus ponderosa sapling water transport. Native percentage loss of conductivity (nPLC), vulnerability to cavitation, and xylem anatomy were assessed in unburned and burned saplings at lethal and non-lethal fire intensities. Fire did not cause any impact on nPLC and xylem cell wall structure in either experiment. However, surviving saplings evaluated 21-months post-fire were more vulnerable to cavitation. Our anatomical analysis in the long-term experiment showed that new xylem growth adjacent to fire scars had irregular-shaped tracheids and many parenchyma cells. Given conduit cell wall deformation was not observed in the long-term experiment, we suggest that the irregularity of newly grown xylem cells nearby fire wounds may be responsible for decreasing resistance to embolism in burned plants. Our findings suggest that hydraulic failure is not the main short-term physiological driver of mortality for Pinus ponderosa saplings. However, the decrease in embolism resistance in fire-wounded saplings could contribute to sapling mortality in the years following fire. This article is protected by copyright. All rights reserved.
Article
Full-text available
Abstract Fire emissions of gases and aerosols alter atmospheric composition and have substantial impacts on climate, ecosystem function, and human health. Warming climate and human expansion in fire‐prone landscapes exacerbate fire impacts and call for more effective management tools. Here we developed a global fire forecasting system that predicts monthly emissions using past fire data and climate variables for lead times of 1 to 6 months. Using monthly fire emissions from the Global Fire Emissions Database (GFED) as the prediction target, we fit a statistical time series model, the Autoregressive Integrated Moving Average model with eXogenous variables (ARIMAX), in over 1,300 different fire regions. Optimized parameters were then used to forecast future emissions. The forecast system took into account information about region‐specific seasonality, long‐term trends, recent fire observations, and climate drivers representing both large‐scale climate variability and local fire weather. We cross‐validated the forecast skill of the system with different combinations of predictors and forecast lead times. The reference model, which combined endogenous and exogenous predictors with a 1 month forecast lead time, explained 52% of the variability in the global fire emissions anomaly, considerably exceeding the performance of a reference model that assumed persistent emissions during the forecast period. The system also successfully resolved detailed spatial patterns of fire emissions anomalies in regions with significant fire activity. This study bridges the gap between the efforts of near‐real‐time fire forecasts and seasonal fire outlooks and represents a step toward establishing an operational global fire, smoke, and carbon cycle forecasting system.
Article
Full-text available
Prescribed burning is used globally to mitigate the risks of wildfires, with severe wildfires increasing in frequency in recent decades. Despite their importance in wildfire management, the nature of future changes to prescribed burn windows under global warming remains uncertain. We use a regional climate projection ensemble to provide a robust spatiotemporal quantification of statistically significant future changes in prescribed burn windows for southeastern Australia. There are significant decreases during months presently used for prescribed burning, that is, in March to May in 2060–2079 versus 1990–2009 across several temperate regions. Conversely, burn windows show widespread significant increases in June to August, that is, months when burns have rarely occurred historically, and also in spring (September–October). Overall, projected changes in temperature and fuel moisture show the most widespread and largest decreases (or increases) in the number of days within their respective ranges suitable for conducting burns. These results support wildfire risk mitigation planning.
Article
Full-text available
Plain Language Summary Recently, catastrophic fires occurred frequently, such as California (2018), Amazon (2019), and Australia (2020), causing tremendous losses to natural resources, human/animal lives, and socioeconomic assets. The fire risks with considerable costs are projected to increase under global warming. To estimate the effects of forthcoming climatic fluctuations on fire activity for large‐scale fire‐prone ecosystems, we need sufficient long‐term information regarding the fire‐fuel‐climate interactions on various spatial‐temporal scales. Notably, widespread grasslands make up roughly 40.5% and 41.7% of the Earth's and China's land surface, respectively. However, Holocene fire dynamics across extensive grassland areas of NW China are not well understood, owing to the scarcity of paleofire records. Here, we provide Holocene sedimentary records of grassland fire and vegetation in Xinjiang of NW China to explore the linkages among fire, fuel, and climate during the Holocene. We suggest that climatic conditions of spring fire‐season and moisture availability are essential for driving the fire‐regime evolution. We find that intensified fire activity has been caused by increased flammability (fire‐season) and enhanced cumulative biomass (fuel‐load) along with increased humidity throughout the Holocene. More importantly, we critically need more grassland paleofire records to understand long‐perspective fire dynamics of interior China.
Article
Full-text available
Dada la creciente ocurrencia e intensidad de los eventos, ya sean causados o no por el cambio climático, es esencial repensar los instrumentos de planificación y gestión del territorio, que en Chile, en el plano comunal,son los Planes Reguladores Comunales (PRC) definidos por la Ley General de Urbanismo y Construcciones y la Ordenanza General de Urbanismo y Construcción (OGUC). Se analizan viviendas instaladas en áreas rurales y periurbanas, sin características técnicas de seguridad contra incendios de fuente interna o externa (interfaz forestal). Esta ausencia de características de seguridad puede deberse a que son desconocidas, no cumplen con las regulaciones, están obsoletas o no hay requisitos para actualizarlas, ya que con frecuencia no están registradas o aprobadas en los municipios. Se revisan las regulaciones chilenas, estadounidenses, europeas y australianas con respecto al desempeño de los edificios y su entorno inmediato, vecindario, ciudad y comuna, entregando estándares de calidad y recomendaciones, incluyendo la gestión de riesgos de desastres. Given the increasing occurrence and intensity of events, whether or not caused by climate change, it’s essential to rethink the territory management and planning instruments, which in Chile are the Communal Regulatory Plans (PRC), General Urban Planning and Construction Law, and General Ordinance of Urbanism and Construction (OGUC). This research analyzes wood houses installed in rural and peri-urban areas, without technical safety features against an internal or external source fire (forest interface). This absence of safety features might be because they are unknown or they don't comply with the regulations, or they are obsolete and there is no requirement to update them since they are frequently not registered or received at the Municipal Works Directorates (DOM). The Chilean, American, European and Australian regulation regarding the buildings performance assurance and their immediate surroundings, neighborhood, town, and commune are reviewed, delivering quality standards and recommendations, including Disaster Risk Management.
Article
Full-text available
There are few observational studies measuring the ecosystem‐scale productivity effects of changes in incident diffuse photosynthetically active radiation (PARdiffuse), especially related to wildfire smoke. Climate change‐induced increases to the duration and intensity of fire conditions have made smoke a common occurrence across western North America, with largely unquantified ecosystem feedbacks. Under equivalent amounts of radiation, increased atmospheric particulate matter could lead to a boost in productivity as scattering redistributes photons throughout multilayer canopies. In this work, we leverage a meso‐network of eddy covariance measurement sites across a unique array of managed and restored C3 and C4 canopy types to understand how recent wildfire smoke affected ecosystem productivity during the summer of 2018, an especially smoky year in the agriculturally productive Central Valley. We find that diffuse PARdiffuse increased by more than a third compared to the previous growing season, while total PAR was only slightly diminished. These conditions caused nearly a doubling of light use efficiency over the range of diffuse fraction observed, with the highest sensitivity to diffuse fraction exhibited by corn and alfalfa crops. We utilized an empirical model to assess the trade‐off between enhanced diffuse fraction and reduced total PAR. Under mean radiation conditions, daily integrated gross ecosystem productivity increased by 1.2–4.2% compared to the previous growing season. Finally, we explore the potential negative effect of heightened ozone, a copollutant often associated with wildfire. In addition to the effects of wildfire smoke, the results of this natural experiment can help validate future predictions of aerosol‐productivity feedbacks.
Article
Increased wildfire activity in many regions in recent decades has increased concerns about the short- and long-term effects on water quantity, quality, and aquatic ecosystem health. Often, loss of canopy interception and transpiration, along with changes in soil structural properties, leads to elevated total annual water yields, peak flows, and low flows. Post-fire land management treatments are often used to promote forest regeneration and mitigate effects to terrestrial and aquatic ecosystems. However, few studies have investigated the longer-term effects of either wildfire or post-fire land management on catchment hydrology. Our objectives were to quantify and compare the short- and longer-term effects of both wildfire and post-fire forest management treatments on annual discharge, peak flows, low flows, and evapotranspiration. We analyzed ten years of pre-fire data, along with post-fire data from 1–7 and 35–41 years after wildfire burned three experimental catchments in the Entiat Experimental Forest (EEF) in the Pacific Northwest, USA. After the fire, two of the catchments were salvage logged, aerially seeded, and fertilized, with the third catchment remained as a burned reference. We observed increases in annual discharge (150–202 %), peak flows (234–283 %), and low flows (~42–81 %), along with decreases in evapotranspiration (34–45 %), across all three study catchments in the first seven year period after the EEF wildfire. Comparatively, annual discharge, peak flows, lows flows, and evapotranspiration had returned to pre-fire levels 35–41 years after the EEF fire in the two salvage logged and seeded catchments. Surprisingly, in the catchment that was burned but not actively managed, the annual discharge and runoff ratios remained elevated, while evapotranspiration remained lower, during the period 35–41 years after the EEF fire. We posit that differences in long-term hydrologic recovery across catchments were driven by delayed vegetation recovery in the unmanaged catchment. Our study demonstrates that post-fire land management decisions have the potential to produce meaningful differences in the long-term recovery of catchment-scale ecohydrologic processes and streamflow.
Article
Full-text available
[1] The area burned by forest fires in Canada has increased over the past four decades, at the same time as summer season temperatures have warmed. Here we use output from a coupled climate model to demonstrate that human emissions of greenhouse gases and sulfate aerosol have made a detectable contribution to this warming. We further show that human-induced climate change has had a detectable influence on the area burned by forest fire in Canada over recent decades. This increase in area burned is likely to have important implications for terrestrial emissions of carbon dioxide and for forest ecosystems.
Article
Full-text available
The International Crown Fire Modelling Experiment (ICFME), carried out between 1995 and 2001 in Canada's Northwest Territories, involved 18 experimental high-intensity crown fires, with more than 100 participants representing 30 organizations from 14 countries. ICFME has provided valuable new data and insights into the nature and characteristics of crowning forest fires, which will assist in addressing fire management problems and opportunities affecting both people and ecosystems in future decades. ICFME evolved as the result of a number of converging issues: the recognition that the US and Canada could not continue separate approaches to fire behaviour model development, the opening of Russia to the western world, increased communication, and the formation of international associations to facilitate collaboration. While the initial impetus for ICFME was the desire to improve the physical modeling of crown fire propagation and spread, the project also created the opportunity to examine many other aspects and impacts of crown fires. This special issue of the Canadian Journal of Forest Research devoted to ICFME is intended to summarize most of the major research results from the project.
Article
Full-text available
The relation between meteorological variables and the monthly area burned by wildfire from May to August 1953-80 in nine Canadian `provinces' was investigated. A purely statistical approach to estimating the monthly provincial area burned, using meteorological variables as predictors, succeeded in explaining 30% of the variance west of Lake Nipigon and about 11% east of Lake Nipigon.Long sequences of days with less than 1.5 mm of rain or days with relative humidities less than 60% proved to have the highest correlation with area burned. These long sequences were assumed to be associated with blocking highs in the westerlies.Bad fire months were independent of rainfall amount but significantly dependent on rainfall frequency, temperature, and relative humidity.
Article
Full-text available
The Canadian Climate Centres General Circulation Model provides two 10-year data sets of simulated daily weather for a large array of gridpoints across North America. A subset of this data, comprised of only those points within the forested part of Canada, was selected for study. Fire season length was calculated front data sets of both the 1 × CO2 and 2 × CO2 runs of the model as well as for the actual climate, using observed data from weather stations. A comparison made between the results of the 1 × CO2 and 2 × CO2 runs indicated a significantly longer fire season across the country under a doubling of atmospheric CO2 levels. Implications of this result, such as a fall fire season in Canada's east and greater strains on management agencies, are discussed.
Article
Full-text available
Large, infrequent fires (LIFs) can have substantial impacts on both ecosystems and the economy. To better understand LIFs and to better predict the effects of human management and climate change on their occurrence, we must first determine the factors that produce them. Here, we review local and regional literature investigating the drivers of LIFs. The emerging conceptual model proposes that ecosystems can be typified based on climatic conditions that determine both fuel moisture and fuel amount. The concept distinguishes three ecosystem types: (1) biomass-rich, rarely dry ecosystems where fuel moisture rather than fuel amount limits LIFs; (2) biomass-poor, at least seasonally dry ecosystems where fuel amount rather than fuel moisture limits LIFs; and (3) biomass-poor, rarely dry ecosystems where both fuel amount and fuel moisture limit the occurrence of LIFs. Our main goal in this paper is to discuss the drivers of LIFs and the three mentioned ecosystem types in a global context. Further, we will discuss the drivers that are not included within the ‘fuels’ versus ‘climate’ discussion. Finally, we will address the question: what kinds of additional information are needed if models predicting LIFs are to be coupled with global climate models? As with all generalizations, there are local deviations and modifications due to processes such as disturbance interaction or human impact. These processes tend to obscure the general patterns of the occurrence of LIFs and are likely to cause much of the observed controversy and confusion in the literature.
Article
Full-text available
"Climate dice," describing the chance of unusually warm or cool seasons, have become more and more "loaded" in the past 30 y, coincident with rapid global warming. The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased. An important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations (3σ) warmer than the climatology of the 1951-1980 base period. This hot extreme, which covered much less than 1% of Earth's surface during the base period, now typically covers about 10% of the land area. It follows that we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming because their likelihood in the absence of global warming was exceedingly small. We discuss practical implications of this substantial, growing, climate change.
Article
Full-text available
Ecological responses to climatic variability in the Southwest include regionally synchronized fires, insect outbreaks, and pulses in tree demography (births and deaths). Multicentury, tree-ring reconstructions of drought, disturbance history, and tree demography reveal climatic effects across scales, from annual to decadal, and from local (�102 km2) to mesoscale (104–106 km2). Climate–disturbance relations are more variable and complex than previously assumed. During the past three centuries, mesoscale outbreaks of the western spruce budworm (Choristoneura occidentalis) were associated with wet, not dry episodes, contrary to conventional wisdom. Regional fires occur during extreme droughts but, in some ecosystems, antecedent wet conditions play a secondary role by regulating accumulation of fuels. Interdecadal changes in fire–climate associations parallel other evidence for shifts in the frequency or amplitude of the Southern Oscillation (SO) during the past three centuries. High interannual, fire–climate correlations (r � 0.7 to 0.9) during specific decades (i.e., circa 1740–80 and 1830– 60) reflect periods of high amplitude in the SO and rapid switching from extreme wet to dry years in the Southwest, thereby entraining fire occurrence across the region. Weak correlations from 1780 to 1830 correspond with a decrease in SO frequency or amplitude inferred from independent tree-ring width, ice core, and coral isotope reconstructions.
Article
Full-text available
The purpose of this study was to compare the sensitivity of modelled area burned to environmental factors across a range of independently-developed landscape-fire-succession models. The sensitivity of area burned to variation in four factors, namely terrain (flat, undulating and mountainous), fuel pattern (finely and coarsely clumped), climate (observed, warmer & wetter, and warmer & drier) and weather (year-to-year variability) was determined for four existing landscape-fire-succession models (EMBYR, FIRESCAPE, LANDSUM and SEM-LAND) and a new model implemented in the LAMOS modelling shell (LAMOS(DS)). Sensitivity was measured as the variance in area burned explained by each of the four factors, and all of the interactions amongst them, in a standard generalised linear modelling analysis. Modelled area burned was most sensitive to climate and variation in weather, with four models sensitive to each of these factors and three models sensitive to their interaction. Models generally exhibited a trend of increasing area burned from observed, through warmer and wetter, to warmer and drier climates with a 23-fold increase in area burned, on average, from the observed to the warmer, drier climate. Area burned was sensitive to terrain for FIRESCAPE and fuel pattern for EMBYR. These results demonstrate that the models are generally more sensitive to variation in climate and weather as compared with terrain complexity and fuel pattern, although the sensitivity to these latter factors in a small number of models demonstrates the importance of representing key processes. The models that represented fire ignition and spread in a relatively complex fashion were more sensitive to changes in all four factors because they explicitly simulate the processes that link these factors to area burned.
Article
Full-text available
Historical relationships between weather, the Canadian fire weather index (FWI) system components and area burned in Canadian ecozones were analysed on a monthly basis in tandem with output from the Canadian and the Hadley Centre GCMs to project future area burned. Temperature and fuel moisture were the variables best related to historical monthly area burned with 36–64% of the variance explained depending on ecozone. Our results suggest significant increases in future area burned although there are large regional variations in fire activity. This was especially true for the Canadian GCM where some ecozones show little change in area burned, however area burned was not projected to decrease in any of the ecozones modelled. On average, area burned in Canada is projected to increase by 74–118% by the end of this century in a 3 × CO2 scenario. These estimates do not explicitly take into account any changes in vegetation, ignitions, fire season length, and human activity (fire management and land use activities) that may influence area burned. However, the estimated increases in area burned would have significant ecological, economic and social impacts for Canada.
Article
Full-text available
The trend in global wildfire potential under the climate change due to the greenhouse effect is investigated. Fire potential is measured by the Keetch-Byram Drought Index (KBDI), which is calculated using the observed maximum temperature and precipitation and projected changes at the end of this century (2070–2100) by general circulation models (GCMs) for present and future climate conditions, respectively. It is shown that future wildfire potential increases significantly in the United States, South America, central Asia, southern Europe, southern Africa, and Australia. Fire potential moves up by one level in these regions, from currently low to future moderate potential or from moderate to high potential. Relative changes are the largest and smallest in southern Europe and Australia, respectively. The period with the KBDI greater than 400 (a simple definition for fire season in this study) becomes a few months longer. The increased fire potential is mainly caused by warming in the U.S., South America, and Australia and by the combination of warming and drying in the other regions. Sensitivity analysis shows that future fire potential depends on many factors such as climate model and emission scenario used for climate change projection. The results suggest dramatic increases in wildfire potential that will require increased future resources and management efforts for disaster prevention and recovery.
Article
Full-text available
1. Studies on the variability of natural fire regimes are needed to understand plant responses in a changing environment. Since vegetation changes might follow or trigger changes in fire frequency, climate models suggest that changes in water balance will accompany current global warming, and the response of fire regimes to Holocene hydro-climate changes and vegetation switches may thus serve as a useful analogue for current change. 2. We present high-resolution charcoal records from laminated cores from three small kettle lakes located in mixed-boreal and coniferous-boreal forest. Comparison with some pollen diagrams from the lakes is used to evaluate the role of the local vegetation in the fire history. Fire frequency was reconstructed by measuring the separation of peaks after detrending the charcoal accumulation rate from any background. 3. Several distinct periods of fire regime were detected with fire intervals. Between c. 7000-3000 cal. year BP, fire intervals were double those in the last 2000 years. Fire frequency changed 1000 years earlier in the coniferous-boreal forest than in the mixed-boreal forest to the south. The absence of changes in combustibility species in the pollen data that could explain the fire frequency transition suggests that the vegetation does not control the long-term fire regime in the boreal forest. 4. Climate appears to be the main process triggering fire. The increased frequency may be the result of more frequent drought due to the increasing influence of cool dry westerly Pacific air-masses from mid to late Holocene, and thus of conditions conducive to ignition and fire spread. In east Canada, this change matches other long-term climate proxies and suggests that a switch in atmospheric circulation 2-3000 years ago triggered a less stable climate with more dry summers. Future warming is moreover likely to reduce fire frequency.
Article
Full-text available
In the boreal forest of North America, as in any fire-prone biome, three environmental factors must coincide for a wildfire to occur: an ignition source, flammable vegetation, and weather that is conducive to fire. Despite recent advances, the relative importance of these factors remains the subject of some debate. The aim of this study was to develop models that identify the environmental controls on spatial patterns in area burned for the period 1980-2005 at several spatial scales in the Canadian boreal forest. Boosted regression tree models were built to relate high-resolution data for area burned to an array of explanatory variables describing ignitions, vegetation, and long-term patterns in fire-conducive weather (i.e., fire climate) at four spatial scales (10(2) km2, 10(3) km2, 10(4) km2, and 10(5) km2). We evaluated the relative contributions of these controls on area burned, as well as their functional relationships, across spatial scales. We also assessed geographic patterns of the influence of wildfire controls. The results indicated that extreme temperature during the fire season was a top control at all spatial scales, followed closely by a wind-driven index of ease of fire spread. However, the contributions of some variables differed substantially among the spatial scales, as did their relationship to area burned. In fact, for some key variables the polarity of relationships was inverted from the finest to the broadest spatial scale. It was difficult to unequivocally attribute values of relative importance to the variables chosen to represent ignitions, vegetation, and climate, as the interdependence of these factors precluded clear partitioning. Furthermore, the influence of a variable on patterns of area burned often changed enormously across the biome, which supports the idea that fire-environment relationships in the boreal forest are complex and nonstationary.
Article
Full-text available
Biomass burning represents an important source of atmospheric aerosols and greenhouse gases, yet little is known about its interannual variability or the underlying mechanisms regulating this variability at continental to global scales. Here we investigated fire emissions during the 8 year period from 1997 to 2004 using satellite data and the CASA biogeochemical model. Burned area from 2001?2004 was derived using newly available active fire and 500 m burned area datasets from MODIS following the approach described by Giglio et al. (2005). ATSR and VIRS satellite data were used to extend the burned area time series back in time through 1997. In our analysis we estimated fuel loads, including peatland fuels, and the net flux from terrestrial ecosystems as the balance between net primary production (NPP), heterotrophic respiration ( R<sub>h</sub> ), and biomass burning, using time varying inputs of precipitation (PPT), temperature, solar radiation, and satellite-derived fractional absorbed photosynthetically active radiation (fAPAR). For the 1997?2004 period, we found that on average approximately 58 Pg C year<sup>?1</sup> was fixed by plants, and approximately 95% of this was returned back to the atmosphere via R<sub>h</sub> . Another 4%, or 2.5 Pg C year<sup>?1</sup> was emitted by biomass burning; the remainder consisted of losses from fuel wood collection and subsequent burning. At a global scale, burned area and total fire emissions were largely decoupled from year to year. Total carbon emissions tracked burning in forested areas (including deforestation fires in the tropics), whereas burned area was largely controlled by savanna fires that responded to different environmental and human factors. Biomass burning emissions showed large interannual variability with a range of more than 1 Pg C year<sup>?1</sup>, with a maximum in 1998 (3.2 Pg C year<sup>?1</sup>) and a minimum in 2000 (2.0 Pg C year<sup>?1</sup>).
Article
Full-text available
Western United States forest wildfire activity is widely thought to have increased in recent decades, yet neither the extent of recent changes nor the degree to which climate may be driving regional changes in wildfire has been systematically documented. Much of the public and scientific discussion of changes in western United States wildfire has focused instead on the effects of 19th- and 20th-century land-use history. We compiled a comprehensive database of large wildfires in western United States forests since 1970 and compared it with hydroclimatic and land-surface data. Here, we show that large wildfire activity increased suddenly and markedly in the mid-1980s, with higher large-wildfire frequency, longer wildfire durations, and longer wildfire seasons. The greatest increases occurred in mid-elevation, Northern Rockies forests, where land-use histories have relatively little effect on fire risks and are strongly associated with increased spring and summer temperatures and an earlier spring snowmelt.
Article
Full-text available
Fire scars in giant sequoia [Sequoiadendron giganteum (Lindley) Buchholz] were used to reconstruct the spatial and temporal pattern of surface fires that burned episodically through five groves during the past 2000 years. Comparisons with independent dendroclimatic reconstructions indicate that regionally synchronous fire occurrence was inversely related to yearly fluctuations in precipitation and directly related to decadal-to-centennial variations in temperature. Frequent small fires occurred during a warm period from about A.D. 1000 to 1300, and less frequent but more widespread fires occurred during cooler periods from about A.D. 500 to 1000 and after A.D. 1300. Regionally synchronous fire histories demonstrate the importance of climate in maintaining nonequilibrium conditions.
Article
A yearly global fire history is a prerequisite for quantifying the contribution of previous fires to the past and present global carbon budget. Vegetation fires can have both direct (combustion) and long-term indirect effects on the carbon cycle. Every fire influences the ecosystem carbon budget for many years, as a consequence of internal reorganization, decomposition of dead biomass, and regrowth. We used a two-step process to estimate these effects. First we synthesized the available data available for the 1980s or 1990s to produce a global fire map. For regions with no data, we developed estimates based on vegetation type and history. Second, we then worked backwards to reconstruct the fire history. This reconstruction was based on published data when available. Where it was not, we extrapolated from land use practices, qualitative reports and local studies, such as tree ring analysis. The resulting product is intended as a first approximation for questions about consequences of historical changes in fire for the global carbon budget. We estimate that an average of 608 Mha yr(-1) burned (not including agricultural fires) at the end of the 20th century. 86% of this occurred in tropical savannas. Fires in forests with higher carbon stocks consumed 70.7 Mha yr(-1) at the beginning of the century, mostly in the boreal and temperate forests of the Northern Hemisphere. This decreased to 15.2 Mha yr(-1) in the 1960s as a consequence of fire suppression policies and the development of efficient fire fighting equipment. Since then, fires in temperate and boreal forests have decreased to 11.2 Mha yr(-1). At the same time, burned areas increased exponentially in tropical forests, reaching 54 Mha yr(-1) in the 1990s, reflecting the use of fire in deforestation for expansion of agriculture. There is some evidence for an increase in area burned in temperate and boreal forests in the closing years of the 20th century.
Article
Historical records of precipitation, streamflow and drought indices all show increased aridity since 1950 over many land areas. Analyses of model-simulated soil moisture, drought indices and precipitation-minus-evaporation suggest increased risk of drought in the twenty-first century. There are, however, large differences in the observed and model-simulated drying patterns. Reconciling these differences is necessary before the model predictions can be trusted. Previous studies show that changes in sea surface temperatures have large influences on land precipitation and the inability of the coupled models to reproduce many observed regional precipitation changes is linked to the lack of the observed, largely natural change patterns in sea surface temperatures in coupled model simulations. Here I show that the models reproduce not only the influence of El Niño-Southern Oscillation on drought over land, but also the observed global mean aridity trend from 1923 to 2010. Regional differences in observed and model-simulated aridity changes result mainly from natural variations in tropical sea surface temperatures that are often not captured by the coupled models. The unforced natural variations vary among model runs owing to different initial conditions and thus are irreproducible. I conclude that the observed global aridity changes up to 2010 are consistent with model predictions, which suggest severe and widespread droughts in the next 30-90 years over many land areas resulting from either decreased precipitation and/or increased evaporation.
Article
Using anomalies calculated from General Circulation Model (GCM) climate predictions we developed scenarios of future fire weather, fuel moisture and fire occurrence and used these as the inputs to a fire growth and suppression simulation model for the province of Ontario, Canada. The goal of this study was to combine GCM predictions with the fire growth and suppression model to examine potential changes in area burned in Ontario due to climate change, while accounting for the large fire suppression activities of the Ontario Ministry of Natural Resources (OMNR). Results indicate a doubling of area burned in the Intensive and Measured fire management zones of Ontario by the decade of 2040 and an eightfold increase in area burned by the end of the 21st century in the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A2 scenario; smaller increases were found for the A1b and B1 scenarios. These changes are driven by increased fire weather conducive to large fire growth, and increases in the number of fires escaping initial attack: for the Canadian GCM's business-as-usual (A2) scenario, escaped fire frequency increased by 34% by 2040 and 92% by the end of the 21st century. Incorporating more detail on large fire growth than previous studies, our model predicts higher area burned under climate change than do these previous studies, as large numbers of high-intensity fires overwhelm suppression capacity.
Article
Wildland fire is ubiquitous. Global wildland fire is the result of the interaction between climate/weather, fuels and people. Our climate is changing rapidly primarily through the release of greenhouse gases that may have profound and possibly unexpected impacts on global fire activity. We review the current understanding of what the future may bring with respect to wildland fire and discusses future options for research and management. To date, research suggests a general increase in area burned and fire occurrence but there is a lot of spatial variability with some areas of no change or even decreases in area burned and occurrence. Fire seasons are lengthening for temperate and boreal regions and this trend should continue in a warmer world. Future trends of fire severity and intensity are difficult to determine due to the complex and non-linear interactions between weather, vegetation and people. Improved fire data are required along with continued global studies that dynamically include weather, vegetation, people and other disturbances.
Article
Forest fires are a significant and natural element of the circumboreal forest. Fire activity is strongly linked to weather, and increased fire activity due to climate change is anticipated or arguably has already occurred. Recent studies suggest a doubling of area burned along with a 50% increase in fire occurrence in parts of the circumboreal by the end of this century. Fire management agencies' ability to cope with these increases in fire activity is limited, as these organizations operate with a narrow margin between success and failure; a disproportionate number of fires may escape initial attack under a warmer climate, resulting in an increase in area burned that will be much greater than the corresponding increase in fire weather severity. There may be only a decade or two before increased fire activity means fire management agencies cannot maintain their current levels of effectiveness.
Article
Boreal forest dynamics are largely driven by disturbance, and fire is a prevalent force of change across the boreal circumpolar region. North American and Eurasian boreal fire regimes are known to be very different but there are few quantitative comparison studies. Russian and Canadian boreal fire regimes are compared using fire weather, fire statistics, fire behaviour, and C emissions data from two large study areas. Fuel consumption, head fire intensity, and C emissions were modelled using fire weather data, fuels data and burned area polygons for all large (200+ ha) fires that occurred in the study areas during 2001–2007. Fire behaviour and C emissions of each large fire were simulated with the Canadian Fire Effects Model (CanFIRE) using fuel type and fuel load data of the burned areas, and Canadian Forest Fire Weather Index System parameters, as interpolated to the fire from the weather station network on the average active fire date. In the Russian study area located in central Siberia, there was an annual average of 1441.9 large fires per 100 M ha of forest land that burned 1.89 M ha (average large fire size = 1312 ha, mean fire return interval = 52.9 years) with an average fire intensity of 4858 kW m−1. In the western Canada study area, there was an annual average of 93.7 large fires per 100 M ha of forest land that burned 0.56 M ha of forest (average large fire size = 5930 ha, mean fire return interval = 179.9 years) with an average fire intensity of 6047 kW m−1. The 2001–2007 fire size distribution and annual area burned in the Canadian study area were very similar to 1970–2009 statistics, although large fire frequency was higher and average large fire size was smaller. Similar long-term fire statistics for Russia currently do not exist for comparison. The C emissions rate (t ha−1 of burned area) was 53% higher in the Canadian study area due to higher pre-burn forest floor fuel loads and higher fuel consumption by crown fires. However, the Russian study area had much higher total C emissions (per 100 M ha of forest area) because of greater annual area burned. The Russian C emissions estimate in this study is likely conservative due to low forest floor fuel load estimates in available datasets. Fire regime differences are discussed in terms of fuel, weather, and fire ecology.
Article
Forest fires are a significant and natural element of the circumboreal forest. Fire activity is strongly linked to weather, and increased fire activity due to climate change is anticipated or arguably has already occurred. Recent studies suggest a doubling of area burned along with a 50% increase in fire occurrence in parts of the circumboreal by the end of this century. Fire management agencies' ability to cope with these increases in fire activity is limited, as these organizations operate with a narrow margin between success and failure; a disproportionate number of fires may escape initial attack under a warmer climate, resulting in an increase in area burned that will be much greater than the corresponding increase in fire weather severity. There may be only a decade or two before increased fire activity means fire management agencies cannot maintain their current levels of effectiveness.
Article
Fire is a common disturbance in the North American boreal forest that influences ecosystem structure and function. The temporal and spatial dynamics of fire are likely to be altered as climate continues to change. In this study, we ask the question: how will area burned in boreal North America by wildfire respond to future changes in climate? To evaluate this question, we developed temporally and spatially explicit relationships between air temperature and fuel moisture codes derived from the Canadian Fire Weather Index System to estimate annual area burned at 2.5° (latitude × longitude) resolution using a Multivariate Adaptive Regression Spline (MARS) approach across Alaska and Canada. Burned area was substantially more predictable in the western portion of boreal North America than in eastern Canada. Burned area was also not very predictable in areas of substantial topographic relief and in areas along the transition between boreal forest and tundra. At the scale of Alaska and western Canada, the empirical fire models explain on the order of 82% of the variation in annual area burned for the period 1960–2002. July temperature was the most frequently occurring predictor across all models, but the fuel moisture codes for the months June through August (as a group) entered the models as the most important predictors of annual area burned. To predict changes in the temporal and spatial dynamics of fire under future climate, the empirical fire models used output from the Canadian Climate Center CGCM2 global climate model to predict annual area burned through the year 2100 across Alaska and western Canada. Relative to 1991–2000, the results suggest that average area burned per decade will double by 2041–2050 and will increase on the order of 3.5–5.5 times by the last decade of the 21st century. To improve the ability to better predict wildfire across Alaska and Canada, future research should focus on incorporating additional effects of long-term and successional vegetation changes on area burned to account more fully for interactions among fire, climate, and vegetation dynamics.
Article
A yearly global fire history is a prerequisite for quantifying the contribution of previous fires to the past and present global carbon budget. Vegetation fires can have both direct (combustion) and long-term indirect effects on the carbon cycle. Every fire influences the ecosystem carbon budget for many years, as a consequence of internal reorganization, decomposition of dead biomass, and regrowth. We used a two-step process to estimate these effects. First we synthesized the available data available for the 1980s or 1990s to produce a global fire map. For regions with no data, we developed estimates based on vegetation type and history. Second, we then worked backwards to reconstruct the fire history. This reconstruction was based on published data when available. Where it was not, we extrapolated from land use practices, qualitative reports and local studies, such as tree ring analysis. The resulting product is intended as a first approximation for questions about consequences of historical changes in fire for the global carbon budget. We estimate that an average of 608 Mha yr−1 burned (not including agricultural fires) at the end of the 20th century. 86% of this occurred in tropical savannas. Fires in forests with higher carbon stocks consumed 70.7 Mha yr−1 at the beginning of the century, mostly in the boreal and temperate forests of the Northern Hemisphere. This decreased to 15.2 Mha yr−1 in the 1960s as a consequence of fire suppression policies and the development of efficient fire fighting equipment. Since then, fires in temperate and boreal forests have decreased to 11.2 Mha yr−1. At the same time, burned areas increased exponentially in tropical forests, reaching 54 Mha yr−1 in the 1990s, reflecting the use of fire in deforestation for expansion of agriculture. There is some evidence for an increase in area burned in temperate and boreal forests in the closing years of the 20th century.
Article
A broad-scale probabilistic model of forest fires, EMBYR, has been developed to simulate the effects of large fires burning through heterogeneous landscapes. Fire ignition and spread are simulated on a gridded landscape by (1) examining each burning site at each time step, (2) independently evaluating the probability of spread to eight neighbors based on fuel type, fuel moisture, wind speed and direction, and (3) distributing firebrands to downwind sites, where the probability of ignition of new fires is a function of fuel type and moisture conditions. Low values for the probability of spread, I, produce a dendritic burn pattern resembling a slow, meandering fire, whereas higher values of I produce solid patterns similar to a rapidly moving, intensely burning fire. I had to be greater than a critical value, ic, estimated to lie between 0.250 and 0.251, to have a 50% chance of propagating across the landscape by adjacent spread alone. The rate of spread of fire at I=0.30 was nearly four times faster when firebrands were included in the simulations, and nearly eight times faster in the presence of moderate wind. Given the importance of firebrands in projecting fire spread, there is a need for better empirical information on fire spotting. A set of model parameters was developed to represent the weather conditions and fuel types on the subalpine plateau of Yellowstone National Park, WY, USA. Simulation experiments were performed to reveal relationships between fire and landscape-scale heterogeneity of fuels. In addition, EMBYR was used to explore fire patterns in the subalpine plateau by simulating four scenarios of weather and fuel conditions. The results of repeated simulations were compared by evaluating risk (the cumulative frequency distribution of the area burned) as a function of the change in weather conditions. Estimates of risk summarized the high degree of variability experienced in natural systems, the difficulty of predicting fire behavior when conditions are near critical thresholds, a quantification of uncertainties concerning future weather conditions, and useful tool for assessing potential wildfire effects.
Article
Wildland fires burn several hundred millio n hectares of vegetation every year, and increased fire activity has been reported in many global regions. Many of these fires have had serious negative impacts on human safety, health, regional economies, global climate change, and ecosystems in non - fire - prone biomes. Worldwide fire suppression expenditures are rapidly increasing in an attempt to limit the impact of wildland fires. To mitigate fire - related problems and costs, forest and land management agencies, as well as land owners and communities, requ ire an early warning system to identify critical periods of extreme fire danger in advance of their potential occurrence. Early warning of these conditions allows fire managers to implement fire prevention, detection, and pre - suppression plans before fire problems begin. Fire danger rating is commonly used to provide early warning of the potential for serious wildfires based on daily weather data. Fire danger information is often enhanced with satellite data, such as hot spots for early fire detection, and with spectral data on land cover and fuel conditions. Normally, these systems provide a 4 - to 6 - hour early warning of the highest fire danger for any particular day that the weather data is supplied. However, by using forecasted weather data, as much as 2 weeks of early warning can be provided. This paper presents a proposed Global Early Warning System for Wildland Fire to provide advanced early warning capabilities at local to global levels.
Article
The Goddard Institute for Space Studies (GISS) general circulation model (GCM) is used to study the possible implications of past and future climate change on global lightning frequencies. Two climate change experiments were conducted: one for a 2 x CO2 climate (representing a 4.2 degs C global warming) and one for a 2% decrease in the solar constant (representing a 5.9 degs C global cooling). The results suggest at 30% increase in global lightning activity for the warmer climate and a 24% decrease in global lightning activity for the colder climate. This implies an approximate 5-6% change in global lightning frequencies for every 1 degs C global warming/cooling. Both intracloud and cloud-to-ground frequencies are modeled, with cloud-to-ground lightning frequencies showing larger sensitivity to climate change than intracloud frequencies. The magnitude of the modeled lightning changes depends on season, location, and even time of day.
Article
It is difficult to find references to fire in general textbooks on ecology, conservation biology or biogeography, in spite of the fact that large parts of the world burn on a regular basis, and that there is a considerable literature on the ecology of fire and its use for managing ecosystems. Fire has been burning ecosystems for hundreds of millions of years, helping to shape global biome distribution and to maintain the structure and function of fire-prone communities. Fire is also a significant evolutionary force, and is one of the first tools that humans used to re-shape their world. Here, we review the recent literature, drawing parallels between fire and herbivores as alternative consumers of vegetation. We point to the common questions, and some surprisingly different answers, that emerge from viewing fire as a globally significant consumer that is analogous to herbivory.
Article
Forest fires constitute one of the most serious environmental problems in several forested regions of India. In the Indian sub-continent, relatively few studies have focused on the assessment of biophysical and anthropogenic controls of forest fires at a landscape scale and the spatial aspects of these relationships. In this study, we used fire count data sets from satellite remote sensing data covering 78 districts over four different states of the Deccan Plateau, India, for assessing the underlying causes of fires. Spatial data for explanatory variables of fires pertaining to topography, vegetation, climate, anthropogenic and accessibility factors have been gathered corresponding with fire presence/absence. A logistic regression model was used to estimate the probability of the presence of fires as a function of the explanatory variables. Results for fire area estimates suggested that, of the total fires covering 47,043km(2) that occurred during the year 2000 for the entire Indian region, 29.0% occurred in the Deccan Plateau, with Andhra Pradesh having 13.5%, Karnataka 14.7%, Kerala 0.1%, and Tamilnadu 1.15%. Results from the logistic regression suggest that the strongest influences on the fire occurrences were the amount of forest area, biomass densities, rural population density (PD), average precipitation of the warmest quarter, elevation (ELE) and mean annual temperature (MAT). Among these variables, biomass density (BD) and average precipitation of the warmest quarter had the highest significance, followed by others. These results on the best predictors of forest fires can be used both as a strategic planning tool to address broad scale fire risk concerns, and also as a tactical guide to help forest managers to design fire mitigation measures at the district level.
Conversion of Williams severity rating for use with the fire weather index
  • C E Van Wagner
Van Wagner, C.E., 1970. Conversion of Williams severity rating for use with the fire weather index. Can. Dep. Fish. For., Can. For. Serv., Rep. PS-X-21. Petawawa, ON. Van Wagner, C.E., 1987. Development and structure of the Canadian Forest Fire Weather Index System. Can. For. Serv., For. Tech. Rep. 35, Ottawa, ON.
R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing
  • R Development
  • Core Team
R Development Core Team, 2011. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3- 900051-07-0. <http://www.R-project.org/>.
Xconv/Convsh (Version 1.91). Software
  • J Cole
Cole, J., 2009. Xconv/Convsh (Version 1.91). Software. <http://badc.nerc.ac.uk/help/ software/xconv/>.
Global pyrogeography: macro-scaled models for understanding the current and future distribution of fire
  • M A Krawchuk
  • M A Moritz
  • M.-A Parisien
  • J Van Dorn
  • K Hayhoe
Krawchuk, M.A., Moritz, M.A., Parisien, M.-A., Van Dorn, J., Hayhoe, K., 2009. Global pyrogeography: macro-scaled models for understanding the current and future distribution of fire. Public Libr. Sci. (PLOS One) 4. http://dx.doi.org/10.1371/ journal.pone.0005102.
Fire Season Severity Rating. Department of Northern Affairs and National Resources, Forestry Branch, Headquarters. Forest Research Division Technical Note 73