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The physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change

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... Elevating air temperature and the enhanced intensity and fre-35 quency of extreme weather events, such as floods, heatwaves, droughts and wildfires, 36 which are accompanied by global warming, have already resulted in spatial redistribution 37 and phenological changes in species and loss of biodiversity [1,2,3,4]. According to pre-38 dictions, if no immediate actions are taken, a 1.5 °C increase in the average global temper- 39 ature from the preindustrial level may lead to an estimated 50% loss of plant, animal, and 40 insect species [5], ultimately jeopardizing their services to the human society and ecosys-41 tems [6]. ...
... In this study, the annual 448 mean temperature in the seven locations included in the sample ranged from 7.0 to 22.6 449 °C (Table S), and most potato production areas are located in these thermal zones [89]. 450 IPCC [5] predicts that the average air temperature in the next 20 years will increase by 451 ~1.5 °C if there is no concerted effort to reduce greenhouse gas emissions. The 25 °C ex-452 perimental temperature used in our study represents the expected up-boundary of the 453 future air temperature in the pathogen distribution zones. ...
... Therefore, 463 future disease quarantine should pay remarkable attention to P. infestans from high-tem-464 perature areas, such as low latitudes and altitudes [58]. 465 In addition to the increase in average air temperature, global warming is expected to 466 escalate the intensity of temperature fluctuations spatiotemporally including the fre-467 quency of extreme temperature events [5,92]. As P. infestans populations originating from 468 warmer places are found to be more thermophilic and demonstrate a broader thermal 469 niche than those originating from cooler places (Figures 2 and 4), P. infestans from warmer 470 regions are more aggressive and might be a greater threat to future food production than 471 those from cooler regions [93], further suggesting that future disease quarantine should 472 pay greater attention to pathogens from high temperature areas. ...
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Knowledge of pathogen adaptation to global warming is important for predicting future disease epidemics and food production in agricultural ecosystems; however, the patterns and mechanisms of such adaptation in many plant pathogens are poorly understood. Here, population genetics combined with physiological assays and common garden experiments were used to analyze the genetics, physiology, and thermal preference of pathogen aggressiveness in an evolutionary context using 140 Phytophthora infestans genotypes under five temperature regimes. Pathogens originating from warmer regions were more thermophilic and had a broader thermal niche than those from cooler regions. Phenotypic plasticity contributed ~10-fold more than heritability measured by genetic variance. Further, experimental temperatures altered the expression of genetic variation and the association of pathogen aggressiveness with the local temperature. Increasing experimental temperature enhanced the variation in aggressiveness. At low experimental temperatures, pathogens from warmer places produced less disease than those from cooler places; however, this pattern was reversed at higher experimental temperatures. These results suggest that geographic variation in the thermal preferences of pathogens should be included in modelling future disease epidemics in agricultural ecosystems in response to global warming, and greater attention should be paid to prevent the movement of pathogens from warmer to cooler places.
... An additional analysis was conducted to compare the carbon stock changes of five scenarios, which provides insights into the benefits of urban tree utilization in retaining carbon in diverse carbon pools, in addition to the net GWP as presented in Figure 1A. Figure S2 shows the carbon stock changes after 100 years (the same time frame of the IPCC GWP characterization factors used in this study 57 ) in five scenarios, compared with the original carbon stored in the raw urban tree waste. Due to the slow decay in landfills, scenario 1 maintains the highest carbon stock (16.9 ...
... 46,56 GWP was calculated using IPCC 2013 characterization factor and eutrophication potential was estimated using TRACI 2.1. 33,57,75 Biogenic and fossil carbon was tracked separately. The variations of key process parameters were collected from the literature. ...
... [117][118][119][120][121][122] In this study, the time horizon for GWP is 100 years. 57 Hence, the landfill decay time for GWP accounting equals 100 years minus the time length of lumber usage phase. GHG and nitrogenor phosphorus-containing emissions of lumber landfill were estimated using the method documented in section ''urban tree waste landfill.'' ...
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Substantial urban tree waste is generated and underutilized in the US. Circular utilization of urban tree wastes has been explored in the literature, but the life-cycle environmental implications of varied utilization pathways have not been fully understood. Here we quantify the life-cycle environmental benefits of utilizing urban tree wastes at process, state, and national levels in the US. Full utilization of urban tree wastes to produce compost, lumber, chips, and biochar substantially reduces nationwide global warming potential (127.4–251.8 Mt CO2 eq./year) and eutrophication potential (93.9–192.7 kt N eq./year) compared with landfilling. Such benefits vary with state-level locations due to varied urban tree waste availability and types. Process-level comparisons identify the most environmentally beneficial combination as using merchantable logs for lumber and residues for biochar. The results highlight the climate change and eutrophication mitigation potential of different circular utilization pathways, supporting the development of circular bioeconomy in the urban environment.
... sjonen av klimagasser i atmosfaeren er nå høyere enn den noen gang har vaert de siste 800.000 år. Det vil føre til en betydelig endring i jordas klima med global oppvarming som resultat (Field mfl. 2014). Temperaturøkningene vil ikke vaere like store over hele verden, men sannsynligvis høyere på nordlige breddegrader enn det globale gjennomsnittet (Stocker mfl. 2013). ...
... Kunnskapen om framtidas klimaendringerhvor fort og hvor mye klimaet vil endre seger imidlertid ufullstendig og usikker, og endringene er bl.a. avhengige av utviklingen av klimagassutslipp (Stocker mfl. 2013). Det er derimot en generell enighet blant forskere om at utslipp av klimagasser i atmosfaeren vil ha betydelige konsekvenser for klimaet og livet på jorden. Dagens klimaforskning kommer ikke med absolutte svar, men gir en indikasjon på hvilke klimaendringer som kan forventes (Flaete mfl. 2010, Stocker mfl. 2013. ...
... e av utviklingen av klimagassutslipp (Stocker mfl. 2013). Det er derimot en generell enighet blant forskere om at utslipp av klimagasser i atmosfaeren vil ha betydelige konsekvenser for klimaet og livet på jorden. Dagens klimaforskning kommer ikke med absolutte svar, men gir en indikasjon på hvilke klimaendringer som kan forventes (Flaete mfl. 2010, Stocker mfl. 2013. ...
... By 'living well', we understand that we are free from loans and subsequent tensions; we have capital/savings in our hands; we can afford our healthcare costs; we can support our children's education and nutritious food; and we can wear good clothes [FGD7-NJLIP-F-DA-21/11/2019]. 1 As highlighted by the latest Intergovernmental Panel on Climate Change report (IPCC, 2022), the spectre of chronic climate change brings into sharp relief the condition of people living with heightened levels of climate vulnerability and its effect on their wellbeing. Bangladesh presents a rich context for exploring this climate vulnerability-resilience-wellbeing nexus for it is considered a 'hotspot' for climate-induced shocks and stresses (Eckstein, Künzel, and Schäfer, 2021;IPCC, 2021). Wellbeing, as shown in this paper, for disadvantaged communities in Bangladesh's climate vulnerable zones is typically viewed through the prism of basic needs, as illustrated in the above quote. ...
... Climatic change is expected to impact the poor disproportionately (Mendelsohn, Dinar, and Williams, 2006). Disadvantaged groups in the world's least developed countries (e.g., South Asia and Sub-Saharan Africa) are particularly vulnerable to direct climate shocks and stresses, and indirect nonclimatic socio-political processes due to their higher sensitivity and low capacity to cope and adapt (IPCC, 2021). Social protection-defined "as the set of policies and programmes designed to reduce and prevent poverty and vulnerability across the life cycle" (ILO, 2017, p. 2)-is recognised as an essential development policy instrument for building the resilience of vulnerable people and systems to climate-related shocks and stresses because of its economic (protective, preventive, promotive) and transformative functions (Devereux and Sabates-Wheeler, 2004;Ulrichs, Slater, and Costella, 2019). ...
Article
As climate change accelerates, the popularity of adaptive social protection over conventional social assistance programmes is on the rise for they are seen to enhance people's resilience and wellbeing outcomes. Despite this upsurge, little is known about the impacts of adaptive programmes on resilience and wellbeing outcomes compared to conventional programmes. We analyse the economic functions that social protection programmes offer through empirical studies in two climate-vulnerable zones in Bangladesh. By operationalising a simplified analytical framework to understand subjective resilience, the qualitative data show the adaptive programme to be more effective in enhancing beneficiaries' perceived resilience to climate risks. Regrettably, neither programme is found to contribute much significantly in terms of enabling beneficiaries to achieve desired wellbeing outcomes that one might expect to see from social protection. The analysis offers rich insights about the design components of the programmes, affording an on-the-ground understanding of their implications for resilience and wellbeing.
... Since the first studies that glimpsed the increase in the average temperature of our planet, global warming and its consequence, Climate Change, has become one of the main challenges for the world and, as a matter of fact, society considers Climate Change a major threat for the present way of living and that it will strongly affect many ecosystems and living species around the world [1,2]. This problem is tightly connected with the emission of the so-called greenhouse gases (GHG), among which are methane (CH 4 ), nitrous oxides (NO x ), or hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and mainly carbon dioxide (CO 2 ), emitted in a natural or anthropogenic way. ...
... The importance of CO 2 is notorious; in 2018, it was estimated as 81% of all GHGs emitted anthropogenically in the USA [3]. The reduction of the anthropogenic component of the GHG emissions has thus become one of the significant challenges for world economies due to the connection between global warming, desertification, rising of the oceans, heat waves, extreme weather events or floods, according to recent International Panel for Climate Change (IPCC) [1] and World Meteorological Organization [4] reports. Furthermore, Climate Change affects people's way of living in most deprived places, reducing or ending their livelihoods and traditional way of life. ...
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This paper aims to analyse and compare the driving forces of the carbon dioxide emissions of the six highest emitters of the world, namely, China, the United States of America, the European Union, India, Russia, and Japan, which are responsible for more than the 67% of the emissions, during the period 1990-2018. The analysis is based on an enlarged Kaya-LMDI decomposition, considering five driving forces and a Granger causality study. Both techniques allow us to disentangle the relationship among the different driving forces and how they change from country to country. The main conclusion from the Kaya-LMDI analysis is that economic growth has been the main driving force that increases CO 2 emissions, and to a much lesser extent, the increase in population in most of the six analysed economies. On the other hand, energy intensity is the main factor for decreasing CO 2 emissions. Surprisingly enough, the end-use fuel-mix term seldom contributes to the decrease of the emissions, which proves that the use of renewable energy still should be largely promoted. It is worth highlighting the different behaviour observed between the four developed countries and the two most populous developing ones, China and India. The Granger-causality analysis suggests that GDP Granger causes energy intensity in the developed countries; however, GDP and renewable energy consumption Granger cause 1 CO 2 emissions only in one case. Highlights: • China and India should largely improve their energy intensity and energy mix contributions to reduce their CO 2 emissions. • The USA and the EU own promising trends concerning energy intensity and energy mix contributions capable of reducing their global CO 2 emissions. • Granger causality analysis suggests that CO 2 and GDP Granger cause most of the rest of driving forces. • Emission intensity of China, India and Russia is around four times larger than the one of the USA, the EU and Japan.
... R apid climate change is expected to impact woody plants across biomes, yet the trends observed in recent decades are seasonally heterogeneous and spatially variable 1 . An increase in temperature, outpacing the global average, is turning high-elevation ecosystems into hotspots of climate warming 2,3 . ...
... The limitation of summer growth can therefore be interpreted as a reaction to unusually high summer temperatures, triggering increased transpiration after depletion of snowmelt water in spring, which brings growth processes to a halt 35,52 . Thus, the observed summer dormancy of tundra shrubs is most likely a result of the species' sensitivity to changing thermal conditions, with rapidly warming summers 1,8 and positive effects of the predicted lengthening of the growing season due to climate change 3 might be counteracted by these environmental constraints. ...
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Under climate change, cold-adapted alpine ecosystems are turning into hotspots of warming. However, the complexity of driving forces of growth, associated biomass gain and carbon storage of alpine shrubs is poorly understood. We monitored alpine growth mechanisms of six common shrub species across contrasting biomes, Mediterranean and tundra, using 257 dendrometers, recording stem diameter variability at high temporal resolution. Linking shrub growth to on-site environmental conditions, we modelled intra-annual growth patterns based on distributed lag non-linear models implemented with generalized additive models. We found pronounced bimodal growth patterns across biomes, and counterintuitively, within the cold-adapted biome, moisture, and within the drought-adapted biome, temperature was crucial, with unexpected consequences. In a warmer world, the Mediterranean alpine might experience strong vegetation shifts, biomass gain and greening, while the alpine tundra might see less changes in vegetation patterns, minor modifications of biomass stocks and rather browning.
... S-band radars are the most popular used for large-scale weather detection by international agencies (e.g., the US National Weather Service), as this band receives almost no interference or attenuation from other atmospheric constituents. Cloud detection radars are at higher frequencies -often in the Ka (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) or W bands (75-100 GHz), which correspond to maximum atmospheric transmission for those phenomena. Conversely, on the other end of the spectrum, L-band radars (1-2 GHz) are used mainly by aircrafts for clear air turbulence detection. ...
... At the fundamental level, understanding and accurately capturing energy imbalances on Earth impact scientists' estimation of equilibrium climate sensitivity (ECS) -i.e., the total heating which Earth will experience because of increased greenhouse gas forcing once the system reaches equilibrium. Current estimates of ECS range widely from our climate models -from 1.5 to 4.5 °C for a doubling of CO 2 [38]. Therefore, we currently have very large uncertainties in our global climate projections of future temperature and circulation patterns. ...
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Spectrum technologies are shaping the way our world connects, communicates, and functions. Radio nodes connect through a nearly ubiquitous wireless mesh of other nodes, access points, satellites, and base stations to support an ever-expanding panorama of applications, spanning communication, autonomous navigation and transportation, radar-based geo-sciences, soil-sciences, renewable energy, space surveillance, environment and healthcare, smart buildings and grids, precision agriculture, consumer and industrial Internet-of-Things (IoT), and other elements of the emerging smart world. This paper offers an overview on the impact of the current and future diverse applications on the radio spectrum. Specific applications to be addressed include astronomy, health, atmospheric, geosciences, and wildfire monitoring. These applications along with many other emerging applications highlight the critical need of implementation of Intelligent Radios and dynamic spectrum access techniques that enable efficient spectrum management.
... As a consequence of global climate change, MSL is projected to increase by 0.26-0.82 m by 2100 (IPCC, 2013;IPCC, 2014), with some models projecting an upsurge of more than 1 m by 2100 (Richardson et al., 2009;Vermeer and Rahmstorf, 2009;Rignot et al., 2011). In addition to the melting of polar caps, the warming of the oceans will also contribute to the global SLR, because of the decrease in density of water with temperature. ...
... According to their projections, salinity levels above 39‰ will be experienced in the area of the Red Sea, the African countries in the Mediterranean, the countries in the Persian Gulf and the Bengal Gulf and Indochina, as well as the Victoria state and the Northern Territory in Australia (Figure 1). In fact, salinization prompted by the SLR varies geographically, because of the spatial variability of regional trends caused by smaller-scale alterations in water temperature, surface winds and geologic activity (IPCC, 2013). Heterogeneity is driven, among other factors, by the salinity of nearby sea surface layers. ...
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Soil salinization caused by sea level rise threatens coastal agricultural soils and geochemically important wetlands worldwide. The aim of this review is to outline expected changes in soil biological activity by discussing the combined effects of salt stress and flooding on plants productivity and soil microbial communities, which determine consequences on fluxes of C, N and P. Finally, it outlines the expected repercussions on greenhouse gases emissions. The prediction of outcomes is made difficult by the concomitant and sometimes contrasting actions of flooding and seawater intrusion on partly acclimated and non-acclimated environments. Non-salt acclimated plants suffer from osmotic stress, but also from reduced O 2 solubility. Microbial biomass declines with increasing salinity and microbial communities shift in composition. Large concentrations of Cl ⁻ inhibit nitrification, but salinity stimulates N 2 O fluxes. Impacts on C mineralisation rates is variable but enhanced by the larger availability of terminal electron acceptors. The reduction of Fe combined with that of SO 4 ²⁻ could enhance P mobility. Salinization affects methanogenesis which is constrained in favour of SO 4 ²⁻ reduction. Consequences are largely site specific and difficult to predict because of the complex network of processes occurring simultaneously in different compartments (i.e., soil, microbiome, vegetation). The distinction between short and long term effects is also important. A reliable prediction of outcomes at a planetary scale will only result from more precise inventories and monitoring of areas displaying specific similarities and from the implementation from these well-defined data sets of specifically devised models whose results can be finally combined on a weighted basis.
... The conditions resembled a possible climate change scenario for central Europe with increased average annual temperatures and decreased rainfall (Ahlström et al. 2012, IPCC 2013). ...
... It is expected that droughts will become more frequent and more severe (Swann 2018). Furthermore, climate change predictions also include hotter temperatures or changing rainfall patterns (IPCC 2013). In present studies sexual differences are usually addressed in dioecious species often providing more distinct trait features. ...
Thesis
The ongoing climate change is altering the living conditions for many organisms on this planet at an unprecedented pace. Hence, it is crucial for the survival of species to adapt to these changing conditions. In this dissertation Silene vulgaris is used as a model organism to understand the adaption strategies of widely distributed plant species to the current climate change. Especially plant species that possess a wide geographic range are expected to have a high phenotypic plasticity or to show genetic differentiation in response to the different climate conditions they grow in. However, they are often underrepresented in research. In the greenhouse experiment presented in this thesis, I examined the phenotypic responses and plasticity in S. vulgaris to estimate its’ adaptation potential. Seeds from 25 wild European populations were collected along a latitudinal gradient and grown in a greenhouse under three different precipitation (65 mm, 75 mm, 90 mm) and two different temperature regimes (18°C, 21°C) that resembled a possible climate change scenario for central Europe. Afterwards different biomass and fecundity-related plant traits were measured. The treatments significantly influenced the plants but did not reveal a latitudinal difference in response to climate treatments for most plant traits. The number of flowers per individual however, showed a stronger plasticity in northern European populations (e.g., Swedish populations) where numbers decreased more drastically with increased temperature and decreased precipitation. To gain an even deeper understanding of the adaptation of S. vulgaris to climate change it is also important to reveal the underlying phylogeny of the sampled populations. Therefore, I analysed their population genetic structure through whole genome sequencing via ddRAD. The sequencing revealed three major genetic clusters in the S. vulgaris populations sampled in Europe: one cluster comprised Southern European populations, one cluster Western European populations and another cluster contained central European populations. A following analysis of experimental trait responses among the clusters to the climate-change scenario showed that the genetic clusters significantly differed in biomass-related traits and in the days to flowering. However, half of the traits showed parallel response patterns to the experimental climate-change scenario. In addition to the potential geographic and genetic adaptation differences to climate change this dissertation also deals with the response differences between the sexes in S. vulgaris. As a gynodioecious species populations of S. vulgaris consist of female and hermaphrodite individuals and the sexes can differ in their morphological traits which is known as sexual dimorphism. As climate change is becoming an important factor influencing plant morphology it remains unclear if and how different sexes may respond in sexually dimorphic species. To examine this question the sex of each individual plant was determined during the greenhouse experiment and the measured plant traits were analysed accordingly. In general, hermaphrodites had a higher number of flowers but a lower number of leaves than females. With regards to the climate change treatment, I found that hermaphrodites showed a milder negative response to higher temperatures in the number of flowers produced and in specific leaf area (SLA) compared to females. Synthesis – The significant treatment response in Silene vulgaris, independent of population origin in most traits suggests a high degree of universal phenotypic plasticity. Also, the three European intraspecific genetic lineages detected showed comparable parallel response patterns in half of the traits suggesting considerable phenotypic plasticity. Hence, plasticity might represent a possible adaptation strategy of this widely distributed species during ongoing and future climatic changes. The results on sexual dimorphism show that females and hermaphrodites are differing mainly in their number of flowers and females are affected more strongly by the experimental climate-change scenario. These results provide a solid knowledge basis on the sexual dimorphism in S. vulgaris under climate change, but further research is needed to determine the long-term impact on the breeding system for the species. In summary this dissertation provides a comprehensive insight into the adaptation mechanisms and consequences of a widely distributed and gynodioecious plant species and leverages our understanding of the impact of anthropogenic climate change on plants.
... Warming-induced destabilization of natural marine CH 4 hydrate has been proposed as a climate warming mechanism that could exhibit threshold behavior, implying that as climate warming continues this feedback could cause an abrupt transition into a warmer climate state. Although crossing such a threshold is deemed as highly unlikely within the next century 16 , this remains a major concern on millennial timescales 4,6,17 . ...
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Continental margin sediments contain large reservoirs of methane stored as gas hydrate. Ocean warming will partly destabilize these reservoirs which may lead to the release of substantial, yet unconstrained, amounts of methane. Anaerobic oxidation of methane is the dominant biogeochemical process to reduce methane flux, estimated to consume 90% of the methane produced in marine sediments today. This process is however neglected in the current projections of seafloor methane release from gas hydrate dissociation. Here, we introduce a fully coupled oxidation module to a hydraulic-thermodynamic-geomechanical hydrate model. Our results show that for seafloor warming rates > 1 °C century⁻¹, the efficiency of anaerobic oxidation of methane in low permeability sediments is poor, reducing the seafloor methane emissions by <5%. The results imply an extremely low mitigating effect of anaerobic oxidation of methane on climate warming-induced seafloor methane emissions.
... When the snow melts, it increases the latent heat sink at the expense of sensible heat, resulting in cooling in the snow-covered regions. Moreover, snow is also a critical component of the hydrological system in middle/high altitude regions, acting as a reservoir of water and a buffer control for river discharge and associated environmental processes (Groisman et al., 1994;You et al., 2002;Barnett et al., 2005;Zhang, 2005;Li et al., 2008;Räisänen, 2008;Zuo et al., 2012;IPCC, 2013;Qin et al., 2014;Huang et al., 2016). ...
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The snow cover extent (SCE) on the southeastern Tibet Plateau (SETP) has an important impact on the dynamics of the East Asian winter monsoon and the runoff changes of the first and third largest rivers in Asia, namely, the Yangtze River and the Yarlung Zangbo River. Unfortunately, the shortness of instrumental SCE data of a few decades limits our ability to understand its long-term variability before the industrial era. Here, we developed Abies faxoniana tree-ring total ring width (TRW), early-wood width (EWW), and late-wood width (LWW) chronologies for the past four centuries at Little Qamdo Village (XQDV), Markam County, on the SETP. The most significant positive correlation (r = 0.62, p < 0.01) was found between the EWW chronology and SCE from March to May (SCE3–5). The SCE would affect the onset of the growing season through soil moisture, restricting the early-wood growth of trees. Thus, we presented a reconstruction of SCE3–5 via EWW chronology since AD 1660 for SETP. We observed two abrupt changes from low to high around the years 1685 and 1998 for our reconstructed SCE3–5. In addition, we found that the positive anomalies of the reconstructed SCE3–5 after 1988 cohered with the distinct increase of the East Asian winter monsoon.
... Dans le monde réel, nous observons une hausse de la température moyenne mondiale, largement considérée comme étant principalement imputable aux émissions humaines de gaz à effet de serre, tels que le dioxyde de carbone, le méthane et l'oxyde nitreux (Stocker et al., 2014). Les projections varient, en fonction du scénario d'émissions et des hypothèses de modélisation, mais les prévisions qui impliquent une augmentation moyenne de la température de 3°C à 4,5°C en 2100 (par rapport à 2000), en l'absence de toute action significative pour réduire les émissions, sont assez typiques (voir Stocker et al. (2014, tableau 12.2)). ...
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Les progrès scientifiques et technologiques pourraient modifier les capacités ou les motivations des individus de manière à déstabiliser la civilisation. Par exemple, les avancées en biohacking pourraient permettre à toute personne ayant une formation de base en biologie de tuer des millions d'individus ; des technologies militaires nouvelles et novatrices pourraient déclencher des courses aux armements dans lesquelles celui qui frappe en premier aurait un avantage décisif ; ou encore, un processus économiquement avantageux pourrait être inventé qui produirait des externalités négatives mondiales catastrophiques difficiles à réguler. Cet article introduit le concept de monde vulnérable : un monde dans lequel il y a un certain niveau de développement technologique auquel la civilisation est presque certainement dévastée par défaut, c'est-à-dire à moins qu'elle n'ait quitté la « condition par défaut semi-anarchique ». Plusieurs vulnérabilités historiques contrefactuelles et spéculatives futures sont analysées et classées dans une typologie. Une capacité générale à stabiliser un monde vulnérable exigerait des capacités considérablement amplifiées en matière de surveillance préventive et de gouvernance mondiale. L'hypothèse du monde vulnérable offre ainsi une nouvelle perspective à partir de laquelle évaluer le rapport coûts-avantages des évolutions vers une surveillance omniprésente ou un ordre mondial unipolaire.
... Understanding how farmers cope and adapt to shocks is important to develop evidence-based policy responses to improve their seed, food, and livelihood security. A meta-study for the Intergovernmental Panel on Climate Change Assessment Report (IPPC AR5) tested the relative adaptation effect of a range of on-farm adaption measures and found cultivar adjustment to be one of the most effective methods (Challinor et al., 2014;IPCC 2014). The most recent IPCC report (AR6) furthermore emphasizes the adaptation potential in crop diversification (IPCC 2022). ...
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Crop diversity plays a central role in smallholder farmers’ ability to cope with and adapt to shocks. Shifting crop varieties and diversifying the crop portfolio are common risk reduction strategies. This paper addresses the influence of covariate climate shocks and idiosyncratic socioeconomic shocks on crop variety use and crop species diversification by smallholder farmers using nationwide balanced panel data(2011/12, 2013/14, & 2015/16) from rural households in Ethiopia combined with village-level historical monthly rainfall and temperature data. We apply correlated random effects models, which control for time-invariant household unobservables. Past exposure to drought shocks increased the use of improved seed varieties in general and for wheat, while long-term average rainfall and lagged flood shocks enhance crop species diversity. Lagged temperature shocks increase improved seed use and crop species diversity. However, recurrent drought exposure and exposure to relatively more severe drought shocks significantly reduced overall agricultural activity. Idiosyncratic shocks, to a much lesser degree, influenced seed use and crop diversification decisions compared to covariate drought shocks. Heterogeneity analysis revealed that drought shock exposure on farmers with less than average farm sizes and other assets -compared to those better-off – increased their relative reliance on local seed use, reduced crop diversification, and reduced improved seed use. The results are robust to various sensitivity checks. Our findings are relevant for policy responses aiming to strengthen smallholders’ ability to cope with and adapt to shocks: farmers’ seed-based risk reduction strategies rely on access to seeds from both formal and informal seed systems, but policies addressing economic inequality are needed to enhance access to improved seeds and crop diversity for resource-poor socioeconomic groups.
... On the other hand, increasing CO 2 is also a common phenomenon in global climate change (Sun et al., 2018). In 2016, the CO 2 concentration was 46% higher than that in pre-industrial times (WMO Greenhouse Gas Bulletin, 2018), and it is predicted to reach 750 ppm by the end of the century (IPCC, 2013). ...
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Key message Being fed on A. artemisiifolia grown under elevated CO 2 and heat wave conditions resulted in the poor performance of O. communa (high mortality, long development period, and low reproduction). Elevated CO 2 and heat waves resulted in the accumulation of secondary metabolites in A. artemisiifolia . After feeding on the secondary metabolites accumulated by A. artemisiifolia , the mortality of O. communa increased.
... At current anthropogenic carbon emission rates, surface seawater pH is predicted to fall below 7.8, and carbonate saturation states (Ω = [Ca 2+ ] × [CO 3 2− ]/K * sp ) will greatly reduce before the end of this century 1 . Such largemagnitude and (geologically) rapid ocean acidification is expected to be a key stressor for marine calcifying organisms 2 , with many studies showing a reduction in stony coral health, abundance, and calcification rates under low seawater pH conditions (e.g. 3 ). ...
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Anthropogenic carbon emissions are causing seawater pH to decline, yet the impact on marine calcifiers is uncertain. Scleractinian corals and coralline algae strongly elevate the pH of their calcifying fluid (CF) to promote calcification. Other organisms adopt less energetically demanding calcification approaches but restrict their habitat. Stylasterid corals occur widely (extending well below the carbonate saturation horizon) and precipitate both aragonite and high-Mg calcite, however, their mode of biocalcification and resilience to ocean acidification are unknown. Here we measure skeletal boron isotopes (δ11B), B/Ca, and U/Ca to provide the first assessment of pH and rate of seawater flushing of stylasterid CF. Remarkably, both aragonitic and high-Mg calcitic stylasterids have low δ11B values implying little modification of internal pH. Collectively, our results suggest stylasterids have low seawater exchange rates into the calcifying space or rely on organic molecule templating to facilitate calcification. Thus, despite occupying similar niches to Scleractinia, Stylasteridae exhibit highly contrasting biocalcification, calling into question their resilience to ocean acidification.
... The East Asian summer monsoon (EASM), an integral part of the global climate system, exerts a significant influence on regional hydrology, ecological environment, and societal stability [1][2][3]. Especially in the context of global warming, the increasing of frequency and magnitude of the extreme precipitation caused a catastrophic impact on regional economic activities and people's lives. Therefore, in order to better understand the global climate evolution and predict the trend of future climate change, it is urgently needed to determine the behavior of the EASM and its underlying forcing mechanism. ...
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To better understand the environmental significance of sediment grain size in continental shelf of the South China Sea (SCS), we carried out a detailed grain size study of sediments from the YJ Core, derived from the mud deposits of the northern SCS. Based on the grain size-standard deviation method, two sensitive grain size components were identified, namely, component 1 (8.2 ~ 9.3 μm) and component 2 (106.8 ~ 120.7 μm), respectively. The results indicate that the sensitive component 1 is likely to derive from fine-grained materials of the Pearl River. These fine-grained materials could be transported by the southwestward coastal current during the wet season, with the domination of the East Asian summer monsoon (EASM). Accordingly, the sensitive component 1 could be sensitive to climate change and has a great potential to reconstruct details of EASM variations. During the period of 7500-6800 cal yr BP, the sensitive component 1 may be controlled by both sea level change and EASM intensity. Besides, the curve of the sensitive component 1 in the YJ Core presents a strong EASM during the interval 6800-3500 cal yr BP and a weak EASM during the period of 3500-2000 cal yr BP, which is synchronous with other paleoclimate records in southern China. In the past 2000 years, the sensitive component 1 may reflect the increasing of human activities. It is essential to carry out more studies with higher resolution in mud areas to clarify a detailed historical evolution of EASM intensity over the whole Holocene.
... One header tank was kept at ambient pH to provide the control treatment while the three others were adjusted for high pCO 2 /low pH treatments. One treatment was adjusted to a stable pH of 7.7, congruent with current predictions for decreases in global ocean surface pH values of 0.3 pH units by the year 2100 (IPCC, 2014). pH levels as low as 7.77 have been observed at 10 m in the habitat of spiny lobsters during upwelling seasons (Kekuewa et al., 2020). ...
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Spiny lobsters rely on multiple biomineralized exoskeletal predator defenses that may be sensitive to ocean acidification (OA). Compromised mechanical integrity of these defensive structures may tilt predator-prey outcomes, leading to increased mortality in the lobsters’ environment. Here, we tested the effects of OA-like conditions on the mechanical integrity of selected exoskeletal defenses of juvenile California spiny lobster, Panulirus interruptus . Young spiny lobsters reside in kelp forests with dynamic carbonate chemistry due to local metabolism and photosynthesis as well as seasonal upwelling, yielding daily and seasonal fluctuations in pH. Lobsters were exposed to a series of stable and diurnally fluctuating reduced pH conditions for three months (ambient pH/stable, 7.97; reduced pH/stable 7.67; reduced pH with low fluctuations, 7.67 ± 0.05; reduced pH with high fluctuations, 7.67 ± 0.10), after which we examined the intermolt composition (Ca and Mg content), ultrastructure (cuticle and layer thickness), and mechanical properties (hardness and stiffness) of selected exoskeletal predator defenses. Cuticle ultrastructure was consistently robust to pH conditions, while mineralization and mechanical properties were variable. Notably, the carapace was less mineralized under both reduced pH treatments with fluctuations, but with no effect on material properties, and the rostral horn had lower hardness in reduced/high fluctuating conditions without a corresponding difference in mineralization. Antennal flexural stiffness was lower in reduced, stable pH conditions compared to the reduced pH treatment with high fluctuations and not correlated with changes in cuticle structure or mineralization. These results demonstrate a complex relationship between mineralization and mechanical properties of the exoskeleton under changing ocean chemistry, and that fluctuating reduced pH conditions can induce responses not observed under the stable reduced pH conditions often used in OA research. Furthermore, this study shows that some juvenile California spiny lobster exoskeletal defenses are responsive to changes in ocean carbonate chemistry, even during the intermolt period, in ways that can potentially increase susceptibility to predation among this critical life stage.
... Climate change is accompanied by an increase in occurrences frequency and intensity of extreme weather occurrences, including droughts, cyclones, floods, heatwaves, extreme rainfalls, cold and heat waves, all of which are projected in several parts of Asia. In recent decades, many countries have been giving high priorities to mitigate the climate change impacts, and they have extended their valuable support to other countries to adapt or reduce the climate change impacts in their respective countries (Stocker et al., 2013). As a result, projected future climate change variabilities globally and within the South Asian countries represents an intensification of present climatic variability rather than the mean climate state (Raswan, 2017). ...
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... If the current trends continue, global warming will reach 1.5°C above preindustrial levels in the early 2030s, which is approximately 10 years earlier than the midpoint of the likely range , and even possibly 3.3-5.7°C by 2100 in high-emission scenarios (IPCC, 2018(IPCC, , 2021. ...
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... including open and built landfills (Wilson, 2015). Leachate control varies throughout the landfills of the growing world and it poses a hazard to local surface and ground water systems (Alam and Ahmade, 2013).The IPCC evaluated that solid waste management represented roughly 3% of worldwide Green House Gases outflows in 2010 with the vast majority of that as an outcome of methane emanations from landfill sites (IPCC, 2013). However, current endeavors to "decouple the loss from the riches" has caused the lower period of waste per unit of Gross domestic product in certain nations, which shows the lucky opening for urban communities to discover higher responses for this basic open bearer of present day cities (UNEP, 2013). ...
... Atmospheric CO2 levels are already rising and will potentially exceed 800 ppm by the ending of the 21 st century. Global surface temperature was estimated to rise by 1.5 °C relative to 1850 by the end of the 21 st century (IPCC 2014). The increasing levels of CO2 and predicted climate change may benefit the establishment and proliferation of weeds over crops which can have negative consequences for agricultural productivity (Peters et al. 2014, Ziska 2007. ...
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Many of the world’s most biodiverse regions are found in the poorest and second most populous continent of Africa; a continent facing exceptional challenges. Africa is projected to quadruple its population by 2100 and experience increasingly severe climate change and environmental conflict—all of which will ravage biodiversity. Here we assess conservation threats facing Africa and consider how these threats will be affected by human population growth, economic expansion, and climate change. We then evaluate the current capacity and infrastructure available to conserve the continent’s biodiversity. We consider four key questions essential for the future of African conservation: (1) how to build societal support for conservation efforts within Africa; (2) how to build Africa’s education, research, and management capacity; (3) how to finance conservation efforts; and (4) is conservation through development the appropriate approach for Africa? While the challenges are great, ways forward are clear, and we present ideas on how progress can be made. Given Africa’s current modest capacity to address its biodiversity crisis, additional international funding is required, but estimates of the cost of conserving Africa’s biodiversity are within reach. The will to act must build on the sympathy for conservation that is evident in Africa, but this will require building the education capacity within the continent. Considering Africa’s rapidly growing population and the associated huge economic needs, options other than conservation through development need to be more effectively explored. Despite the gravity of the situation, we believe that concerted effort in the coming decades can successfully curb the loss of biodiversity in Africa.
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Mountain ecosystems, particularly tropical alpine ecosystems, host important biodiversity hotspots in small, primarily remote mountain tops. One of those ecosystems, Afroalpine ecosystems, the habitats above the treeline of tropical African mountains, have experienced long-term spatial isolation and extreme climatic conditions, leading to the formation of "Sky Island" like ecosystems endowed with unique flora and fauna rich in endemics. One of these ecosystems is Ethiopia's Bale Mountains, which is home to Africa's most extensive Afroalpine plateau, Altiplano, with no spacious high summits that provide space for an upward shift. Over the last fifty years, this pristine Afroalpine ecosystem has experienced and suffered from excessive human presence, hence significant LULC change besides climate change. Consequently, the once pristine natural Afroalpine mountain ecosystems have changed entirely cultural landscapes. Lately, the long-existing environmental relationships that shape Afroalpine mountain ecosystems' stability and instability are changing rapidly in response to the recent rapid global change, especially to the synergistic impacts of drivers of ecosystem change such as Land Use Land Cover (LULC) and climate change. Here, we investigated the effects of fifty years long Spatio-temporal LULC change and climate change on Afromontage and Afroalpine vascular plants richness patterners, particularly that of Afroalpine endemics; effects of current and projected variability of temperature and moisture- related predictor on the diversity and distribution of the phenotypically highly adapted dominant cover types; and possible impacts of the synergy between the main drivers of biodiversity change particularly that of LULC and climate change on the Afroalpine vegetation. The research used in-situ plot data, ex-situ open data sources, and state-of-the-art research approaches and methodologies. The fifty-year Spatio-temporal LULC change study identified cover types such as Agricultural Fields, Upper Montane Forest, Afroalpine Grasslands, Afromontane Dwarf Shrubs, and Herbaceous Formations increased overtime. Conversely, Afromontane Grasslands, Closed Erica Forest, Isolated Erica Shrubs, Aroalpine Dwarf Shrubs, and Herbaceous Formations reduced considerably. However, despite some simplification at the lower margins, the Afromontane Rainforest (Harenna Rainforest), located south of the Bale Mountains, has remained relatively stable. Contemporarily, the ecotone between the Upper Montane and the afroalapine ecosystems are "biodiversity loss hotspots." Population growth, infrastructural expansion, frequent fire, over-grazing, deforestation, inadequate conservation and management measures, and lack of protection during the political transition and uncertain political atmosphere are some of the leading local causes of biodiversity loss. Besides, the massive mid to low-altitude areas, formerly sparsely populated agriculturally fertile regions, face large-scale agricultural land acquisition, and land grabbing. LULC change is expected to become even more intensive and is likely to continue imposing unprecedented pressures on the largely endemic biota of the area. Our finding further indicated hump-shaped species richness patterns across the massif. In addition, the proportion of endemic species increases monotonically towards the summit on all slopes. However, climate change will profoundly impact vascular plants' diversity and richness patterns, i.e., it impacts species' and ecosystems' structure, composition, functioning, and distribution patterns. Furthermore, it will results in a shift in ecosystem boundaries, potentially affecting vulnerable Afroalpine ecosystems and their uniquely adapted species. Our study indicated that future climate change would significantly alter species distribution patterns with a pronounced effect on the Afroalpine ecosystems and endemic species restricted to the Afroalpine plateau, e.g., at 2oC, up to 8.6% of total endemics will become extinct. However, all vascular plants and ecosystems will not respond to the change uniformly. The ericaceous woody vegetation, located between the low-elevation Broadleaf Forests and high- elevation Afroalpine vegetation, is anticipated to be affected differently. Our model ensemble projections indicated increased dominance and upward range shift of ericaceous vegetation by the first half of the 21st century. It will increase in the western, northwestern, northern, and eastern parts of the massif and the Sanetti plateau. Towards the turn of the 21st century, ericaceous vegetation will continue to increase across its current range and shift towards the Afroalpine meadow while receding from the lower range across the massif. Moreover, the current ericaceous vegetation range correlates to the current temperature and precipitation trends, reaffirming the critical role of temperature and precipitation in determining species distributions along elevation. The competition between Afroalpine specialists and plants with a broader range of distribution will further facilitate the extinction rate of Afroalpine specialists and endemics. Overall, the dissertation developed innovative research approaches and applied cost-effective and efficient biodiversity monitoring approaches that utilize the vast geospatial data acquired from Remote Sensing and advanced geospatial analysis tools and techniques. In developing countries, environmental management, climate change mitigation, and adaptation decisions are often made without proper consultation with the local stakeholders in a top-down approach that is usually variable with changing government and political transitions. Hence, policy failure and lack of appropriate local conservation and management strategies are the root causes of the Afroalpine biodiversity loss. Therefore, continuous biodiversity monitoring and assessment utilizing state-of- the-art geospatial information and tools and technologies such as Remote Sensing, qGIS, R2, and others are essential. Recently, information acquired from Remote Sensing provides frequent and consistent data that can be traced a few decades back and cover a large swath of land. Our results indicate the high likelihood of considerable changes in this biodiversity hotspot in Eastern Africa.
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Regional flood frequency analysis (RFFA) is a powerful method for interrogating hydrological series since it combines observational time series from several sites within a region to estimate risk-relevant statistical parameters with higher accuracy than from single-site series. Since RFFA extreme value estimates depend on the shape of the selected distribution of the data-generating stochastic process, there is need for a suitable goodness-of-distributional-fit measure in order to optimally utilize given data. Here we present a novel, least-squares-based measure to select the optimal fit from a set of five distributions, namely Generalized Extreme Value (GEV), Generalized Logistic, Gumbel, Log-Normal Type III and Log-Pearson Type III. The fit metric is applied to annual maximum discharge series from six hydrological stations along the Sava River in South-eastern Europe, spanning the years 1961 to 2020. Results reveal that (1) the Sava River basin can be assessed as hydrologically homogeneous and (2) the GEV distribution provides typically the best fit. We offer hydrological-meteorological insights into the differences among the six stations. For the period studied, almost all stations exhibit statistically insignificant trends, which renders the conclusions about flood risk as relevant for hydrological sciences and the design of regional flood protection infrastructure.
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Aim of this work is the assessment of the individual and combined impacts of land use land cover change (LULCC) and inter-decadal climate variations (CV) on the water and energy cycles over India, given extensive land use land cover change over the last decades. In this study, we quantify the contributions of LULC and CV on changes in the water and energy cycles over the Indian subcontinent through a scenario-based approach, with Community Land Model version 4.5 (CLM4.5) model runs from 1981-2010. The approach involves four simulation scenarios: (i) the first scenario considers no LULCC or CV (LULC is fixed and the atmospheric forcings for 1981-1990 are repeated in the decades afterwards); (ii) the second scenario considers only the impact of CV; (iii) the third scenario considers only the effect of LULCC by updating the LULC every 10 years; and (iv) the fourth scenario considers the combined impact of LULCC and CV. LULCC causes an overall decrease in the evapotranspiration (ET) and soil moisture (SM) by 0.3% and 0.1% respectively (comparing 1991-2010 with 1981-1990), while the net radiation changes <1%. On the other hand, CV caused an increase in the ET, SM and net radiation by +5.4%, +1.5% and +1.0% respectively, in spite of decrease of precipitation of 6.6%. The combined effect of LULCC and CV leads to an increase in the overall ET by 3.8%. Among the LULC transitions, deforestation and urbanization are found to be the major causes for hydrological changes over the decades, but their impact is much smaller, since CV has a greater impact on the hydrological cycles over India than LULC. The in-depth understanding of the distinct contributions of LULCC and CV on the water and energy cycles in tropical and subtropical regions can be used for framing future water resources planning and management policies.
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