Figure - available from: Nature Climate Change
This content is subject to copyright. Terms and conditions apply.
Uncertainty in the frequency of compound hot-dry events (fHD) in idealised experiments (Note that an in-depth interpretation of the figure is provided in the Supplementary Material.) Given a present-day bivariate Gaussian distribution of temperature T and precipitation P with a correlation cor(T, P) of -0.5 (first row), 0 (second row), and 0.5 (third row), shading shows the uncertainty in the future fHD associated with uncertainty in the change of mean temperature (left column) and mean precipitation (right column) at given levels of expected changes in mean temperature (shown on the x-axis) and mean precipitation (y-axis). Magenta isolines show the expected fHD resulting from the expected changes in mean temperature and precipitation (they are the same on right and left columns for a given cor(T, P)). The second axes show changes in units of present-day standard deviations. The closed contour shows the kernel density containing 90% of the multimodel mean projected changes in mean temperature and precipitation in units of relative present-day standard deviations over land grid-points (actual changes in ∘C and mm/day are shown in Extended Data Figure 2b and 7b, respectively). The green line indicates changes of equal magnitude in temperature and precipitation, in units of present-day standard deviations. (Note that the difference in magnitude of uncertainty from temperature (left column) and precipitation (right column) results from the fact that the uncertainty in the change of temperature is relatively large compared to the uncertainty in the change of precipitation).
Source publication
Compound hot–dry events—co-occurring hot and dry extremes—frequently cause damages to human and natural systems, often exceeding separate impacts from heatwaves and droughts. Strong increases in the occurrence of these events are projected with warming, but associated uncertainties remain large and poorly understood. Here, using climate model large...
Similar publications
Drought contributed to extensive dieback of southern California chaparral, and normalized difference vegetation index before drought and near the end of the drought was used to estimate this dieback, after accounting for other disturbances recorded in aerial photographs. Within the perimeters of two megafires that occurred after the drought, the 20...
Arid regions are characterized by the fragility of their ecosystems, which are highly vulnerable to climate change. The increase in aridity in these regions makes them more exposed to droughts. This article analyses the trend in aridity and the expansion of drylands in the Wilaya (province) of Naâma, which is an arid region in southwestern Algeria,...
The damage owing to climate change is increasing worldwide. In South Korea, the increase in temperature has exceeded the average global temperature increase. These temperature changes have increased the frequency and damage of droughts. To reduce drought damage, the importance of efficient water management policies and evapotranspiration (an index...
Despite the acceleration of climate change, erroneous assumptions of climate stationarity are still inculcated in the management of water resources in the United States (US). The US system for drought detection, which triggers billions of dollars in emergency resources, adheres to this assumption with preference towards 60-year (or longer) record l...
This study analyzes the impact of climatic conditions on the development of grain and leguminous crops in the Trans-Baikal region. Insufficient precipitation, droughts, early frosts, and a short growing season limit the choice of crops suitable for cultivation in the region. Grain crops, which occupy the largest share of sown areas, are chosen as t...
Citations
... Stomatal movement influences the rates of photosynthesis and respiration, thereby affecting plant water use efficiency and leaf thermal conditions 10,11 . Facing more regular concurrent high temperatures and drought stress in the natural environment [12][13][14][15] , plants need to initiate a range of cellular, physiological and morphological changes to prevent damage and maintain optimal performance 1, [15][16][17] . Opening and closing of stomata are rapid responses that probably require switch-like signalling mechanisms that can swiftly alternate when environmental conditions change. ...
Plants continuously respond to changing environmental conditions to prevent damage and maintain optimal performance. To regulate gas exchange with the environment and to control abiotic stress relief, plants have pores in their leaf epidermis, called stomata. Multiple environmental signals affect the opening and closing of these stomata. High temperatures promote stomatal opening (to cool down), and drought induces stomatal closing (to prevent water loss). Coinciding stress conditions may evoke conflicting stomatal responses, but the cellular mechanisms to resolve these conflicts are unknown. Here we demonstrate that the high-temperature-associated kinase TARGET OF TEMPERATURE 3 directly controls the activity of plasma membrane H⁺-ATPases to induce stomatal opening. OPEN STOMATA 1, which regulates stomatal closure to prevent water loss during drought stress, directly inactivates TARGET OF TEMPERATURE 3 through phosphorylation. Taken together, this signalling axis harmonizes stomatal opening and closing under high temperatures and/or drought. In the context of global climate change, understanding how different stress signals converge on stomatal regulation allows the development of climate-change-ready crops.
... Dry soils and associated land-atmosphere feedbacks are major heatwave drivers ( 9 , 19 , 36 ). It has been found that an amplified warming trend of hot days vs. mean warming in the tropics can largely be explained by a "dry gets hotter" mechanism ( 37 ), while precipitation trends were found to govern the occurrence of hot-dry extremes globally ( 38 ). Huntingford et al. ( 26 ) found regionally varying causes for trends in the yearly 90th percentile of daily temperatures: While in the Northern Hemisphere, extratropics dry soils were emphasized, trends in tropical Africa were linked to increased available energy. ...
... This is consistent with earlier findings ( 39 ) that attributed amplified warming in Mediterranean-type regions. Simpson et al. ( 40 ) found that trends in humidity, which are strongly dependent on the accurate depiction of rainfall patterns ( 38 ), evaporation (which is partially controlled by vegetation), and hydrological characteristics of the land surface, including vegetation are still not accurately reproduced, which could in part explain the discrepancies reported here. Persistent high-pressure systems, which materialize as local blocking patterns ( 41 ) or zonally elongated stationary Rossby waves ( 3 , 42 , 43 ) are important contributors to weather extremes especially in the mid-latitudes ( 44 ). ...
Multiple recent record-shattering weather events raise questions about the adequacy of climate models to effectively predict and prepare for unprecedented climate impacts on human life, infrastructure, and ecosystems. Here, we show that extreme heat in several regions globally is increasing significantly and faster in magnitude than what state-of-the-art climate models have predicted under present warming even after accounting for their regional summer background warming. Across all global land area, models underestimate positive trends exceeding 0.5 °C per decade in widening of the upper tail of extreme surface temperature distributions by a factor of four compared to reanalysis data and exhibit a lower fraction of significantly increasing trends overall. To a lesser degree, models also underestimate observed strong trends of contraction of the upper tails in some areas, while moderate trends are well reproduced in a global perspective. Our results highlight the need to better understand and model the drivers of extreme heat and to rapidly mitigate greenhouse gas emissions to avoid further harm from unexpected weather events.
... As stated by the special report from the IPCC in 2012 [8], various definitions of compound events were proposed [6,9], with more attention given to temperature-precipitation compound events in the context of global warming [10,11], including compound droughtheatwave events (CDHEs) [12,13] and compound heatwave-precipitation events (CH-PEs) [14][15][16]. Thus, many studies focused on the changes in CDHEs and CHPEs at different ...
... Then, the grid CMIP6-MME data for the three future scenarios were bias-corrected by combining the observed meteorological data with the CMIP6 historical Remote Sens. 2024, 16, 4208 7 of 22 data. The precipitation was calculated using Equation (11), and the mean and maximum temperatures were calculated using Equation (12) [72,73]. ...
Compound extreme events can cause serious impacts on both the natural environment and human beings. This work aimed to explore the changes in compound drought–heatwave and heatwave–extreme precipitation events (i.e., CDHEs and CHPEs) across China using daily-scale gauge-based meteorological observations, and to examine their future projections and potential risks using the Coupled Model Intercomparison Project (CMIP6) under the shared socioeconomic pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, and SSP5-8.5). The results show the following: (1) The frequencies of CDHEs and CHPEs across China showed a significant increasing trend from 1961 to 2020, with contrasting trends between the first half and second half of the period (i.e., a decrease from 1961 to 1990 and an increase from 1991 to 2020). Similar trends were observed for four intensity levels (i.e., mild, moderate, severe, and extreme) of CDHEs and CHPEs. (2) All the frequencies under three SSP scenarios will show increasing trends, especially under higher emission scenarios. Moreover, the projected intensities of CDHEs and CHPEs will gradually increase, especially for higher levels. (3) The exposure of the population (POP) and Gross Domestic Product (GDP) will be concentrated mainly in China’s coastal areas. The GDP exposures to the CDHEs and CHPEs will reach their highest values for SSP5-8.5, while the POP exposure will peak for SSP2-4.5 and SSP5-8.5, respectively. Our findings can offer scientific and technological support to actively mitigate future climate change risks.
... However, different directions of phenological change have frequently been reported in the context of current climate warming (Wang et al., 2019a, b;Li et al., 2022). A growing number of studies have focused on the reversal of phenomenon of vegetation phenology (Yang et al., 2014;Li et al., 2018;Liu et al., 2021;Bevacqua et al., 2022;Xiong et al., 2023). For example, in temperate China, the EOS exhibited delays during the 1980s; this trend slowed or even reversed during the 1990s and the 2000s. ...
... In contrast, in the arid southwestern part of the Tibetan Plateau, increased preseason precipitation was found to delay EOS (Shen et al., 2023). This implies that the climate-phenology relationship varies greatly in different regions and vegetation types (Cong et al., 2012;Zhang et al., 2022b) and that the response of vegetation phenology to climate change is complex and changeable (Ganjurjav et al., 2016;Yuan et al., 2020b;Bevacqua et al., 2022). Thus, the present results suggest that a delayed trend in the EOS of typical grasslands is likely Spatial distributions of the cumulative time scales of the response at the end of the growing season (EOS) to monthly total precipitation (PRE) and monthly average temperature (TEM). ...
Climate change has a substantial influence on the end of the growing season (EOS). The time-lag and cumulative effects are non-negligible phenomena when studying the interactions between climate and vegetation. However, quantification of the temporal effects of climatic factors on the EOS in the context of changing hydrothermal patterns remains scarce. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) fraction of absorbed photosynthetically active radiation (FPAR), this study first inverted the EOS of typical steppe vegetation in a semi-arid region of China and then quantified the time-lag and cumulative effects of monthly total precipitation (PRE) and monthly average temperature (TEM) on the EOS during 2003–2022. The results showed that a turning point occurred in 2011, when the EOS displayed an advancing trend until 2011, followed by a delayed trend. Accordingly, the climatic background has changed from warming and drying conditions during 2003–2011 to warming and wetting conditions during 2011–2022. The time-lag scales of PRE and TEM on the EOS decreased from 2- and 4-month scales during 2003–2011, respectively, to 1- and 2-month scales during 2011–2022, respectively. The time-lag degree of the hydrothermal factors on the EOS weakened with increased precipitation. The cumulative time scales of the EOS response to PRE and TEM were mainly concentrated within 1-month during different time periods, but the EOS was more sensitive to short-term precipitation. The time lag and cumulative partial correlation coefficient of PRE to EOS changed from mainly negative regulation during 2003–2011 (39.2% and 50.0%, respectively) to mainly positive regulation during 2011–2022 (67.8% and 93.7%, respectively). The time-lag and cumulative effects of TEM on the EOS were positive with the precipitation and temperature gradient under a warming and wetting climate, which indicated that increased precipitation was a prerequisite for temperature to induce a delayed EOS in the semi-arid study region. This study emphasizes the important role of precipitation in regulating the EOS response to hydrothermal factors in semi-arid regions.
... The global climate has experienced unprecedented warming over the past century, exacerbating the occurrence of extreme weather events (Bevacqua et al., 2022;Qian et al., 2020;Rajeev & Mishra, 2023) and increasing highimpact events such as heatwaves (H. Chen et al., 2022;Fischer & Schär, 2010;Perkins-Kirkpatrick & Lewis, 2020). ...
Heatwaves represent a significant and growing threat to natural ecosystems and socio‐economic structures, making heatwave risk mitigation and prevention an important area of research. In exploring heatwave frequency and intensity from 1901 to 2020, the present study finds a sharp increase in both. The study also finds that the spatial distribution of heatwaves is unequal, the volatility of intensity characteristics has become more prominent over time, and the Gini coefficients of four key heatwave indictors have become larger due to increasing dryness. Although heatwaves occur more frequently in drylands, there is greater cumulative heat in humid areas, resulting in a higher heatwave risk in those areas. The global heatwave risk over the past three decades (1991–2020) has increased nearly five‐fold compared to the early 20th century (1901–1930). Furthermore, GeoDetector analysis indicates that the Palmer drought severity index (PDSI) and downward surface shortwave radiation (Srad) contributing the most in drylands and humid areas (0.29 and 0.41, respectively). The contribution of relative humidity (RH), wind speed (WS), soil moisture (SM), and the normalized difference vegetation index (NDVI) is also significant in humid areas, but is much smaller in drylands. Composite analysis shows that the years with anomalously high heatwave risk correspond to positive anomalies of 500hPa geopotential height and surface pressure. The inhibition of cloud formation due to sinking air and the resulting increase in temperature in the atmosphere may be increasing the risk of heatwave occurrence. This study emphasizes the urgent need to address worsening climate change impacts.
... It has been demonstrated that the occurrence of compound hot and dry extreme events is determined by precipitation trends rather than temperature variation, 20 thereby implying disproportionate variations of different forms of heatwaves compared to the overall changes in heat extremes. In addition, global warming may alter atmospheric circulation 21 and landatmosphere interactions, 22 which can generate heatwaves through differing mechanisms 13 and might therefore lead to varying trends in heat extreme frequency. ...
Heat extremes pose pronounced threats to social-ecological systems and are projected to become more intense, frequent, and longer. However, the mechanisms driving heatwaves vary across heatwave types and are not yet fully understood. Here we decompose perturbations in the surface energy budget to categorize global heatwave-days into four distinct types: sunny–humid (38%), sunny-dry (26%), advective (18%), and adiabatic (18%). Notably, sunny-dry heatwave-days decrease net ecosystem carbon uptake by 0.09 gC m⁻² day⁻¹ over harvested areas, while advective heatwave-days increase the thermal stress index by 6.20 K in populated regions. In addition, from 2000 to 2020, sunny-dry heatwaves have shown the most widespread increase compared to 1979 to 1999, with 67% of terrestrial areas experiencing a doubling in their occurrence. Our findings highlight the importance of classifying heatwave-days based on their underlying mechanisms, as this can enhance our understanding of heatwaves and improve strategies for heat adaptation.
... Xu et al., 2020), hereafter referred to as summerautumn drought (SAD). The 2019 SAD, accompanied by a combination of the lowest precipitation (P) and highest near-surface air temperature (T ) in MLRYR in 1961-2020, caused greater catastrophic impacts than single factor events such as droughts or heatwaves (Bevacqua et al., 2022;Z. Liu & Zhou, 2021;Wouters et al., 2022;Zscheischler et al., 2018). ...
... H. Wu et al. (2021) found an ACCinduced increase in both magnitude and areal extent of dry-hot events over the globe since the 1990s. Under future higher emissions, the increasing trend of dry-hot events will be elevated over the globe (Bevacqua et al., 2022;G. Zhang, Wang, et al., 2022). ...
... Xu et al., 2020). P deficits are directly requisite for the occurrence of droughts (Bevacqua et al., 2022;Diffenbaugh et al., 2015;K. Xu et al., 2020), while rising T amplifies both drought intensity and subsequent disasters by enhancing evapotranspiration (W. ...
Plain Language Summary
The 2019 summer‐autumn drought (SAD) in the middle and lower reaches of the Yangtze River (MLRYR) caused a substantial loss of agriculture and economy. This SAD was accompanied by dry‐hot conditions, that is, high near‐surface temperature (T) and low precipitation (P). The impact of anthropogenic climate change (ACC) on these dry‐hot conditions and the past and future responses of SADs to them is unclear. To understand this, the present study investigates the historical and projected likelihood of dry‐hot conditions and droughts like those of the 2019 SAD under ACC in MLRYR. We found that ACC‐induce increases in T raises the likelihood of dry‐hot conditions from August–November 1901–2020 in MLRYR, as observed in both observations and simulations. The likelihood of SAD occurrence increased from 33.3% in 1901–2000 to 85.7% in 2001–2020 in MLRYR. Under the high‐emission scenario, the frequency of exceptional dry‐hot conditions is projected to increase by +10% per century. ACC‐increased dry‐hot conditions are expected to substantially elevate the likelihood of such SAD events as the 2019 event from 1.59% (1961–2020) to 17.82% (2041–2100). These findings help us understand how ACC influences the past and future likelihood of dry‐hot conditions and SAD occurrences in MLRYR.
... Following Bevacqua et al (2022), our analysis focuses on the compound extremes on global land (excluding Antarctica) during the warm season, when the impacts are typically more pronounced (Zscheischler and Seneviratne 2017, Russo et al 2019, Ionita et al 2021). The warm season is defined as the entire year for tropical areas between 15 • S and 15 • N, June-July-August for the Northern Hemisphere over 15 • N, and December-January-February for the Southern Hemisphere over 15 • S (Freychet et al 2021). ...
... The physical basis of the emergent relationship can be elucidated as follows. Uncertainties in mean precipitation trends are strongly influenced by largescale atmospheric circulation patterns (Martin 2012, Bevacqua et al 2022, and the variability in these circulation patterns plays a significant role in climate warming (Feng et al 2016). Meanwhile, changes in atmospheric circulation contribute substantially to extreme temperature and precipitation events (Swain et al 2016). ...
... There are several limitations that need to be acknowledged for better interpreting the findings of this study. Firstly, our definition of compound f HD events is based on historical exceedance thresholds, which is a widely used indicator for defining extreme events (Freychet et al 2021, Bevacqua et al 2022, Thackeray et al 2022. To note that the interpretation of future extreme events can strongly depend on how 'extreme' is defined (Karl et al 1999, Pendergrass 2018, we conducted a sensitivity analysis using historical exceedance thresholds of 95% for temperature and 5% for precipitation (figure S11). ...
The frequency of compound hot–dry events (fHD) is projected to increase significantly with future warming, yet associated uncertainties remain considerable and poorly constrained. In this study, we constrain future projections of fHD (2070–2099) using observations of recent trends in temperature (T) and precipitation (P) (1980–2014) during the warm-seasons. The physical mechanism is that the variance of fHD across climate models is dominated by their projected changes in P (ΔP), which can be constrained by recent trends in T and P. Compared to the raw projections, the observationally constrained fHD is reduced by 9.68%–18.74%, with uncertainty narrowed by 3.79%–10.66% under the high emission scenario. The highest decline of fHD is located in regions with low population and gross domestic product (GDP), and globally, population and GDP exposures to fHD are reduced by 6.02%–10.73% and 6.51%–12.03%, respectively. The observationally constrained fHD with lower uncertainty provides more reliable information for risk management under climate change.
... 14 Depending on the dimensionality of the event under study, the sample size required to robustly assess climatological distributions-let alone changes therein-can be multiple times larger than for univariate events. 13,15 It would take a prohibitive amount of time for the observational record to become long enough to enable robust empirical statistics, time that is typically not available under the pressure of adaptation planning for ongoing climate change. ...
... While future warming is virtually certain to reduce surface water availability, impactful droughts almost always start with a lack of rain, so better constraining precipitation projections will remain critically important to accurately predict future water availability and hydrologic compound events. 15,41,42 For the uncertainty decomposition in Figure 1, individual simulations from CMIP6 models were used. Using SMILEs instead results in a similar picture, though internal variability becomes relatively more important in that case ( Figure S1). ...
Some of the most impactful climate and weather events result from compounding drivers. To robustly assess the current and future risk from such compound events, a better understanding of the associated sources of uncertainty is needed. Internal variability confounds detection and attribution of human-induced climate change and imposes irreducible limits on the accuracy of climate projections. Response uncertainty can lead to divergent projections for many societally important quantities such as precipitation. Combined with unknown future greenhouse gas emissions, these uncertainties can result in a socio-economically paralyzing range of future storylines. Climate model large ensembles are uniquely positioned to assess these uncertainties and are rightfully gaining popularity in compound event research, but they need to be accompanied by rigorous model validation and robust observational constraints to reach their full potential in terms of usefulness for practitioners. This perspective discusses these opportunities and challenges at the example of water resources and provides an outlook on application-oriented compound event research with large ensembles.
... [1][2][3] These extreme events are driven by complex interactions among physical processes and initiated by similar synoptic circulation anomalies, 4,5 and they often co-occur. 6,7 As droughts occur more frequently and temperature warming triggers stronger land-atmosphere feedbacks, 8 compound drought-heatwave (CDHW) events have increased globally, 9,10 including in Asia, 11,12 Europe, 13,14 North America, 15 South America, 16 and Oceania, 17,18 amplifying adverse impacts on socio-ecosystem sustainability and human health. 19,20 SCIENCE FOR SOCIETY Droughts and heatwaves are becoming increasingly common. ...
