Frequency Of Climate Extremes Research Articles

Joint Probability Analysis of the Rich‐Poor Runoff and Sediment Discharge in Karst Watersheds

AbstractAs one of the largest contiguous karst landscapes in the world, southwest China has experienced severe soil erosion because of its frequent climate extremes, special hydrogeology, shallow and discontinuous soil, steep topography, and inappropriate land use. Furthermore, the construction of dams in recent decades has rendered the relationship between runoff and sediment discharge increasingly complex. However, the joint probability distributions and joint return periods of runoff‐sediment discharge relationship are still not clear. The objective of this study was to investigate the synchronous‐asynchronous probabilities and return periods of rich‐poor combinations of annual runoff and sediment discharge using a bivariate copula function to assess the risk of soil erosion in four selected karst watersheds in southwest China. Results showed that sediment discharge has declined significantly in all watersheds except Liujiang, and annual runoff and sediment discharge were significantly positively correlated in all watersheds. The optimal marginal distribution and the best copula function of annual runoff and sediment discharge are not identical for each watershed. The synchronous and asynchronous probabilities of annual runoff and sediment discharge are close to 1:1 in the Wujiang watershed. The asynchronous probability is much higher for the combination of less runoff with more sediment discharge (r < s) than for the combination of more runoff with less sediment discharge (r > s) in Nanpanjiang. Therefore, the risk of soil erosion may be higher in the Wujiang and Nanpanjiang watersheds. The joint return periods of runoff‐sediment discharge were concentrated in less than 5 years during the historical period. These return periods can provide data references for designing the scale of water resources projects and help in better soil erosion control in the future. This study could be a technical reference for identifying the non‐stationarity of the multivariate relationship between runoff and sediment discharge in karst regions.

Nutrition-sensitive climate risk across food production systems

Abstract Global nutrition targets remain unmet, as over half of preschool-aged children and two-thirds of non-pregnant women of reproductive age worldwide suffer from micronutrient deficiencies. Climate change poses a growing threat to global food and nutrition security, but existing climate risk assessments often overlook the critical roles of both terrestrial and aquatic nutrient-rich foods that are vital for dietary diversity and micronutrient supply. In this study, we introduce an innovative framework that integrates data on future climate extremes, nutrient supply dependencies, and diet-related climate vulnerability. Our comprehensive analysis assesses nutrition-sensitive climate risk to five essential micronutrients across production systems. By mid-century (2041-2060), we estimate that 75% of calcium, 30% of folate, 39% of iron, 68% of vitamin A, and 79% of vitamin B12 produced in primary food products will face frequent climate extremes (at least every other year) globally. Nearly fifty countries are projected to face high domestic climate risk for two or more micronutrients during this period, with ten countries facing high risk across all five. We outline distinct climate risk profiles to offer data-driven entry points into strategies for bolstering the resilience of micronutrient supply chains and advancing progress toward global nutrient targets in the face of a changing climate.

Vapor pressure deficit and temperature variability drive future changes to carbon sink stability in China’s terrestrial ecosystems

The stability of future carbon sinks is crucial for accurately predicting the global carbon cycle. However, the future dynamics and stability of carbon sinks remain largely unknown, especially in China, a significant global carbon sink region. Here, we examined the dynamics and stability of carbon sinks in China’s terrestrial ecosystems from 2015 to 2,100 under two CMIP6 scenarios (SSP245 and SSP585), using XGBoost and SHAP models to quantify the impact of climatic drivers on carbon sink stability. China’s future terrestrial ecosystems will act as a “carbon sink” (0.27–0.33 PgC/yr), with an initial increase that levels off over time. Although the carbon sink capacity increases, its stability does not consistently improve. Specifically, the stability of carbon sinks in future China’s terrestrial ecosystems transitions from strengthening to weakening, primarily occurring in areas with higher carbon sink capacity. Further analysis revealed that atmospheric vapor pressure deficit (VPD) and temperature (Tas) are the two primary factors influencing carbon sink stability, with significant differences in their impacts across different scenarios. Under the SSP245 scenario, variations in VPD (VPD.CV) regulate water availability through stomatal conductance, making it the key driver of changes in carbon sink stability. In contrast, under the SSP585 scenario, although VPD.CV still plays an important role, temperature variability (Tas.CV) becomes the dominant factor, with more frequent extreme climate events exacerbating carbon cycle instability. The study highlights the differences in driving factors of carbon sink stability under different scenarios and stresses the importance of considering these differences, along with the scale and stability of carbon sinks, when developing long-term carbon management policies to effectively support carbon neutrality goals.

Ecological Connectivity of River‐Lake Ecosystem: Evidence From Fish Population Dynamics in a Connecting Channel

AbstractClimate change and human activities, for example, dam construction, largely affect hydrologic and hydrodynamic processes of river‐lake system, and hence exerted serious pressure on its aquatic ecology. It's challenging to restore its ecological environment without systematic investigation and knowledge about the features of hydrodynamics, water quality, and aquatic ecology. This study conducted field surveys of hydrodynamic, water quality, and fish distribution in the Yangtze‐Poyang system, the largest river and largest fresh lake in China, to investigate the effects of hydrologic and hydrodynamic variations on fish population dynamics, especially the extreme drought and its effects were largely concerned. In two surveys, discharge decreased from 12,000 m3/s to less than 1,000 m3/s. Distinct differences on fish density, species composition, and populations connectivity between two surveys were observed. During high‐water, connecting channel secured effective transition of river‐lake habitats, its strong hydrological connectivity and flow heterogeneity supported great biodiversity and bidirectional populations connectivity. Limited flow space and elevated turbidity during low‐water confined fish to a few channel units with sufficient depth and width, increasing fish density up to 7 times greater than during high‐water, and seriously weakening ecological connectivity of the system. Furthermore, species interaction was intensified due to limited environmental capacity, periodic strategists were favored while opportunistic strategists visibly diminished, leading to a dramatic decline in species by nearly half. In the future with increasingly frequent extreme climate, engineering measures, for example, effective ecological project regulation, are needful to alleviate the drought problem, being of great significance for maintaining ecological connectivity within the river‐lake system.

Aridity-dependent resistance but strong resilience of grassland ANPP to naturally occurring precipitation extremes

Abstract Increasing intensity and frequency of climate extremes under climate change are expected to affect rainfall-constrained ecosystems, particularly grassland ecosystems in arid and semi-arid zones. However, our understanding of the effects of precipitation extremes (extreme drought or wetness) on grassland productivity, especially under naturally occurring conditions, remains limited. Here, we assembled a dataset of aboveground net primary productivity (ANPP) measurements from long-term (26–54 years) observational studies conducted in 13 grasslands worldwide to investigate the direct and legacy responses of grassland ANPP to naturally occurring precipitation extremes. We further examined changes in plant community structure (species richness, life history, growth form and photosynthetic pathway) before, during and after precipitation extremes. We found that extreme drought decreased ANPP by an average of 40%, while extreme wetness had a neutral effect on ANPP. The direct effects of both extreme drought and wetness on ANPP were aridity-dependent, with grassland vulnerability increasing with site aridity. However, we did not detect widespread legacy effects of extreme drought or wetness on ANPP. This is mainly attributable to reorganized plant community structure, which favored rapid recovery of community biomass. The aridity-dependent response of ANPP to precipitation extremes demonstrates the ambient climate-dependent resistance of grasslands to these events. Moreover, the minimal legacy effects of precipitation extremes on ANPP highlight the strong resilience of grasslands. These findings underscore the importance of integrating extreme climate conditions into forecasts of future grassland productivity and stability in a changing climate.

Spatial and Temporal Variations’ Characteristics of Extreme Precipitation and Temperature in Jialing River Basin—Implications of Atmospheric Large-Scale Circulation Patterns

In recent years, extreme climate events have shown to be occurring more frequently. As a highly populated area in central China, the Jialing River Basin (JRB) should be more deeply explored for its patterns and associations with climatic factors. In this study, based on the daily precipitation and atmospheric temperature datasets from 29 meteorological stations in JRB and its vicinity from 1960 to 2020, 10 extreme indices (6 extreme precipitation indices and 4 extreme temperature indices) were calculated. The spatial and temporal variations of extreme precipitation and atmospheric temperature were analyzed using Mann–Kendall analysis, to explore the correlation between the atmospheric circulation patterns and extreme indices from linear and nonlinear perspectives via Pearson correlation analysis and wavelet coherence analysis (WTC), respectively. Results revealed that among the six selected extreme precipitation indices, the Continuous Dry Days (CDD) and Continuous Wetness Days (CWD) showed a decreasing trend, and the extreme precipitation tended to be shorter in calendar time, while the other four extreme precipitation indices showed an increasing trend, and the intensity of precipitation and rainfall in the JRB were frequent. As for the four extreme temperature indices, except for TN10p, which showed a significant decreasing trend, the other three indices showed a significant increasing trend, and the number of low-temperature days in JRB decreased significantly, the duration of high temperature increased, and the basin was warming continuously. Spatially, the spatial variation of extreme precipitation indices is more obvious, with decreasing stations mostly located in the western and northern regions, and increasing stations mostly located in the southern and northeastern regions, which makes the precipitation more regionalized. Linearly, most of the stations in the extreme atmospheric temperature index, except TN10p, show an increasing trend and the significance is more obvious. Except for the Southern Oscillation Index (SOI), other atmospheric circulation patterns have linear correlations with the extreme indices, and the Arctic Oscillation (AO) has the strongest significance with the CDD. Nonlinearly, NINO3.4, Pacific Decadal Oscillation (PDO), and SOI are not the main circulation patterns dominating the changes of TN90p, and average daily precipitation intensity (SDII), maximum daily precipitation amount (RX1day), and maximum precipitation in 5 days (Rx5day) were most clearly associated with atmospheric circulation patterns. This also confirms that atmospheric circulation patterns and climate tend not to have a single linear relationship, but are governed by more complex response mechanisms. This study aims to help the relevant decision-making authorities to cope with the more frequent extreme climate events in JRB, and also provides a reference for predicting flood, drought and waterlogging risks.

Hydraulic conductivity regulates tree growth and drought resistance in semi-arid mixed forests of northern China

With the intensification of climate warming, drought has become increasingly severe. Drought seriously impacts tree growth and may even result in tree mortality. However, our understanding of how the hydraulic structure of xylem in different tree species regulates growth and drought resistance remains incomplete. Here, we collected tree-ring samples from three semi-arid natural Chinese pine (Pinus tabuliformis)-broadleaf mixed forests in northern China. We selected Chinese pine (non-porous wood), white birch (Betula platyphylla, diffuse-porous wood), and Liaodong oak (Quercus liaotungensis, ring-porous wood) as target tree species. Using dendrochronology and wood anatomy methods, we evaluated interspecies differences in tree growth, climate sensitivity, and drought resistance, and analyzed the relationships between tree growth, drought resistance, and theoretical xylem-specific hydraulic conductivity (Ks). Our findings revealed distinct differences in the hydraulic structure of xylem among these three tree species as well as their resilience to drought. Liaodong oak exhibited less sensitive to drought compared to Chinese pine and white birch. Meanwhile both Chinese pine and Liaodong oak demonstrated greater resistance to drought than white birch. The positive correlation between specific xylem hydraulic conductivity and both tree growth and drought resistance were observed for Chinese pine, but Liaodong oak was the opposite. This suggested that specific hydraulic conductivity of xylem cannot serve as a consistent or robust predictor of tree growth or drought resistance across different species. As climate warming intensifies, it is anticipated that white birch may experience severe and significant irreversible decline in growth, while Liaodong oak may exhibit the highest potential growth performance. Given the projected intensification of future warming trends along with more frequent extreme climate events, safeguarding biodiversity and productivity within semi-arid Chinese pine-broadleaf mixed forests may hinge on the prioritizing protection efforts for Chinese pine.

Distribution, ecology, and threats assessment of 11 endemic frankincense tree taxa (Boswellia) in the Socotra Archipelago (Yemen)

Societal Impact StatementConserving frankincense trees (Boswellia) is crucial for both ecological and socio‐economic reasons. Surveying these trees in the field and using remote sensing unmanned aerial vehicles in the Socotra Archipelago, we found that Socotran frankincense trees are threatened by forest fragmentation, overgrazing, and increasingly frequent extreme climate events. A better understanding of the distribution and the threats of these important insular species will improve the conservation policy of the local authorities and benefit local communities in the Socotra Archipelago. At the same time, this work serves as a good practice example to guide conservation efforts for other culturally important threatened tree species around the world, therefore helping to sustain local livelihoods, fostering ecological resilience, and supporting socio‐economic stability.Summary Globally, frankincense trees (Burseraceae: Boswellia) are increasingly under threat because of habitat deterioration, climate impacts, and the olibanum trade. Despite harboring nearly half of the species in the genus, up‐to‐date insights are lacking for the insular endemic frankincense trees of the Socotra Archipelago UNESCO (United Nations Educational, Scientific and Cultural Organization) World Heritage Site (Yemen). We combined georeferencing of individual trees in the field with remote sensing applying unmanned aerial vehicles (UAVs) to evaluate Boswellia distribution and (sub)population sizes in the entire Socotra Archipelago. We counted 17,253 trees across all 11 taxa and we surveyed almost 55% directly in the field, collecting individual information on threats and health indicators. We estimate that the current total population sizes of the relatively common Socotran Boswellia taxa (Boswellia elongata, Boswellia popoviana, and Boswellia ameero) consist of a few thousand mature individuals with fragmented distribution of which a large proportion occurs in highly disjunct relictual stands, while the more range‐restricted species survive only through a few hundred (Boswellia nana and Boswellia samhaensis) to fewer than a hundred trees (Boswellia scopulorum). Our field data show that the Socotran frankincense trees are threatened by fragmentation and overgrazing resulting in a lack of natural regeneration, in combination with effects of extreme climate events (e.g., higher frequency and intensity of cyclones and prolonged drought) and potential future infrastructure developments; the species are less impacted by resin collection. We provide recommendations to strategize urgent protection of the declining Socotran frankincense trees, and we update their conservation status, resulting in an endangered status for seven and a critically endangered status for four taxa.

Increases and decreases in soil moisture in water‐limited plant communities cause asymmetrical responses in biomass but not in diversity

AbstractAimsChanges in precipitation patterns, such as the predicted increases in the frequency of climatic extremes, are likely to alter plant communities, but whether responses to drought or to wetter conditions respectively cause consistent, opposite responses is debated. Here, we assessed the response in biomass production and species diversity of water‐limited plant communities to the direction (increase or decrease) and magnitude (micro‐ and macro‐climatic effects) of changes in soil moisture.LocationWe reciprocally translocated soils containing seed banks from two climates (semi‐arid and mediterranean) at a micro‐climatic (opposite slopes) and a macro‐climatic scale (between climates) in Chile.ResultsBiomass production for the soils that were translocated from wetter to drier climates was unrelated to the available soil moisture. The lowest biomass was produced in the wettest climate on the wet slope. Biomass production increased after a translocation to the drier climate (representing the largest change in climate). Nonetheless, the highest overall biomass for the wet to dry translocation was produced on the mediterranean dry slope with intermediate soil moisture. However, on the same mediterranean dry slope, biomass was almost zero for soil translocated the other way round (from drier to wetter). Diversity after 24 months was unaffected by micro‐climatic change, but soils transplanted toward the drier climate yielded a plant community with increased diversity.ConclusionOur results showed direction and magnitude of climate change but also the response factor that is studied matters to detect direction‐dependent responses; i.e., species richness had a linear and reversible response. However, the response of biomass depended on the origin of the transplanted material (soil and plant community), indicating history dependence (hysteresis). This emphasizes that responses to unidirectional climate manipulation experiments may not be able to capture the entire nature of the response of plant communities to climate change.

Discovery of a novel series of phenylthiazole thioether (sulfone) compounds based on natural thiasporine A as potential candidates for controlling rice fungal and bacterial diseases

AbstractHalf of the world's population depends on rice for their calories. Protecting rice in the growth period from damage caused by phytopathogens is faced with a great challenge under the frequent extreme climate. To find novel fungicides to control rice diseases, 35 novel phenylthiazole‐1,3,4‐oxadiazole‐thioether (sulfone) derivatives were synthesized and evaluated for their efficacy against destructive fungal and bacterial diseases of rice. Bioassay results demonstrated that most of G‐series compounds possessed excellent antifungal and antibacterial activities. In particular, compounds G1 (EC50 = 2.22 μg/mL, R.s) and G7 (EC50 = 2.76 μg/mL, R.s) showed the most promising antifungal activities in vitro and exhibited superior protective and curative activities against rice sheath blight in vivo compared with commercial carbendazim. Surprisingly, compound G2 exhibited the remarkable antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo) with an EC50 value of 1.98 μg/mL, and demonstrated superior protective activity (88.08%) than thiodiazole copper (79.39%) against rice bacterial leaf blight at 200 μg/mL. The abovementioned results fully manifested that the phenylthiazole‐1,3,4‐oxadiazole‐sulfone structure, especially compounds G1 and G2, had the potential to develop as commercial agents for controlling rice fungal and bacterial diseases.

New assessment protocols to improve building envelope resilience

The current regulations on building envelope requirements are no longer related only to aspects of energy efficiency or guarantee of durability over time, but also to new performance scenarios concerning technological systems in relation to adaptation, mitigation and resilience to increasingly frequent extreme climate events. The research aims to analyse causes, effects and potential strategies to increase the resilience of the building envelope in case of extreme events, proposing solutions to reduce the consequences of the impact of flying debris on the building envelope. The contribution is the result of a research activity conducted within the HORIZON METABUILDING LABS Innovation research project.

Uncovering the evolution of ozone pollution in China: A spatiotemporal characteristics reconstruction from 1980 to 2021

Ozone pollution emerged as a significant environmental concern in China in recent years. Given the enduring impact of anthropogenic activities on the atmosphere, understanding the long-term evolutionary patterns of ozone pollution is crucial for effective pollution mitigation strategies. However, there have been limited studies to reconstruct spatiotemporal continuity ozone concentrations in China since 1980. In this research, monthly MDA8 ozone concentrations from 1980 to 2021 were first estimated by reproducing the numerical relations between ozone pollution and the atmospheric environment based on a machine learning approach. The verification results from temporal, spatial, and sample-based cross-validation methods demonstrated the model performance in simulating MDA8 ozone concentration spatiotemporally, with correlation coefficients (R) ranging from 0.76 to 0.79, mean square error (RMSE) ranging from 22.72 μg·m−3 to 24.28 μg·m−3, and mean absolute error (MAE) ranging from 17.06 μg·m−3 to 18.25 μg·m−3. The evolution of ozone pollution in China can be delineated into two phases, characterized by an increasing trend since 2001, coinciding with significant rises in average annual temperature and hot weather frequency over the past four decades. The 90th percentile of ozone concentration from 2001 to 2021 increased by 1.79% compared to the period from 1980 to 2001. Notably, ozone episodes have expanded beyond summer months, partly due to global warming and frequent extreme climate events, contributing to an annual temperature increase of 0.03 °C. Despite several pollutant emission restrictions since 2013, the ozone pollution in China has persisted due to the increased emissions of VOCs. Spatially, severe ozone pollution hotspots are evident in Xinjiang province, the Jing-Jin-Ji urban agglomeration, and Northeast China, with notable increases observed in Tibet and the Guangdong-Hong Kong-Macao Greater Bay Area over the past six years. Moreover, the influence factors were identified by the average reduction of node impurity calculation. The evolution of ozone pollution was inextricably linked to solar radiation and atmospheric temperature, which played pivotal positive roles in ozone formation. Whilst, there is significant heterogeneity in the effect of meteorological conditions on ozone concentrations due to the disparity between land and oceanic climates.

How extreme hydrological events correspond to climate extremes in the context of global warming: A case study in the Luanhe River Basin of North China

AbstractThe consensus on climate warming is well‐established, and extreme values inherently encapsulate more information than averages. Against the backdrop of frequent extreme climate events, studying extreme values holds profound significance. This study aims to reveal the characteristics of extreme climate events and their role in triggering extreme hydrological events in the typical North China basin, that is, the Luanhe River Basin. Trends of 25 extreme climate indices during 1960–2018 are analysed using the Sen's slope and MK significance test to study the changing characteristics of extreme climate. Characteristics of extreme flood and dry events are examined, encompassing trend analyses at different time scales (seasonal, interannual, decadal) and concentration analysis. Finally, and most significantly, correlation analysis is conducted on extreme climate indices and features of extreme hydrological events, followed by principal component analysis of extreme climate indices, to precisely quantify the impact of extreme climate on the occurrence of extreme hydrological events. The results indicate a warming trend in extreme temperature indices, with a more significant rise in minimum temperatures compared to maximum temperatures. There is a significant decrease in precipitation, but precipitation at higher magnitudes is less affected by the overall reduction in total precipitation. Extreme dry events have markedly increased, particularly concentrated in winter with delayed occurrences, primarily induced by extreme temperature events, that is, warming effects. Conversely, extreme flood events have significantly decreased, mainly concentrated in summer and early autumn, predominantly caused by extreme precipitation and extreme high‐temperature events. The climate and hydrological conditions in the study area have become more extreme and complex. Severe river droughts may occur more frequently in winter, while extreme flooding may happen in summer. Therefore, it is necessary to pay more attention to these developments.

Awareness begets action: public climate attention and corporate green innovation

ABSTRACT In this study, we examine the effect and mechanism of public climate attention on corporate green innovation. We find that green innovation strengthens with increasing degrees of public climate attention. Moreover, the impact of public climate attention on green innovation is more significant when enterprises face more green development pressure and hold more resource reserves. Further investigation reveals that public climate attention contributes more to green innovation in samples of state-owned enterprises (SOEs), non-high-tech companies, and under more frequent extreme climate disasters. Finally, based on the differences in firm motivation for engaging in green innovation, we also explore the influence of public climate attention on firms’ substantive and strategic green innovations and find that public climate attention significantly contributes to both types of innovation. Our research results are of theoretical and practical significance for achieving dual-carbon goals and promoting sustainable social development and high-quality economic development.

Seed Germination Characteristics of a Critically Endangered Evergreen Oak—Quercus marlipoensis (Fagaceae) and Their Conservation Implications

Seed germination is among the most crucial and vulnerable stages in plant life cycles. Quercus marlipoensis is a critically endangered sclerophyllous oak. Only one population has ever been found worldwide in the tropical montane cloud forests of southeastern Yunnan, China, and it has shown difficulties with regeneration. However, its seed biological traits and key restrictive germination factors remain unknown. We investigate the impacts of scarification, temperature, and water potential on the seed germination of Q. marlipoensis. Results show that the seeds show typical epicotyl dormancy. The seed germination increased when removing part or all of the pericarp and part of the cotyledon (one-third and two-thirds). The seeds can germinate at 5 to 30 °C, but the highest T50 was achieved at 25 °C. When the water potential decreased from 0 to −1.0 MPa, the germination rate decreased but the germination time increased. Q. marlipoensis seeds are typically recalcitrant and highly sensitive to moisture loss, but the species can tolerate animal predation and low germination temperatures. The more frequent climatic extremes and droughts in the Indo-China region will severely degrade its natural habitats. Therefore, ex situ conservation to preserve its germplasm and introduce seedlings into a suitable habitat are essential for its conservation management.

Amplified Production and Export of Dissolved Inorganic Carbon During Hot and Wet Subtropical Monsoon

AbstractUnderstanding the origins and processes of riverine dissolved inorganic carbon (DIC) is crucial for predicting the global carbon cycle with projected, more frequent climate extremes yet our knowledge has remained fragmented. Here we ask: How and how much do DIC production and export vary across space (shallow vs. deep, uphill vs. depression) and time (daily, seasonal, and annual)? How do the relative contributions of biogenic (soil respiration) and geogenic (carbonate weathering) sources differ under different temperature and hydrological conditions? We answer these questions using a catchment‐scale reactive transport model constrained by stream flow, stable water isotopes, stream DIC, and carbon isotope data from a headwater karstic catchment in southwest China in a subtropical monsoon climate. Results show climate seasonality regulates the timing of DIC production and export. In hot‐wet seasons, high temperature accelerates soil respiration and carbonate weathering (up to a factor of three) via elevating soil CO2 and carbonate solubility, whereas high discharge enhances export by two orders of magnitude compared to cold‐dry seasons. Carbonate weathering is driven more by soil CO2 than water flow. At the annual scale, 92.9% and 7.1% of DIC was produced in shallow and deep zone, respectively, whereas 64.5% and 35.5% of DIC was exported from shallow and deep zone, respectively. These results highlight the uniqueness of subtropical karst areas as synchronous reactors and transporters of DIC during the hot‐wet monsoon, contrasting the asynchronous production and export in other climate regions. A future hotter and wetter climate with more intensive storms in the region may further intensify DIC production and export, accentuating the potential of subtropical karst regions as global hot spots for carbon cycling.

The effect of climate change on crop yield anomaly in Europe

AbstractEvery human needs sufficient, safe, and nutritious food to live an active and healthy life. Climate change, especially more frequent extreme climate events, increasingly affects crop yields. Unpredictable losses in crop production pose a high risk to our food systems, thus threatening agricultural producers and consumers worldwide. This study analyzes the effect of climate change on wheat, maize, and barley yield anomalies for the major producing countries in the EU. Applying the Random Forest machine learning model, climate indicators, comprising mean and extreme climate conditions, explain 18% of crop yield anomalies across crops and countries from 1961 to 2020. The predictive power of climate indicators is highest for maize with 24%, followed by barley with 22% and wheat with 3%. However, mean climate indicators are stronger associated with crop yield anomalies than extreme climate indicators. Temperature‐ and soil moisture–related indicators are more important than precipitation‐related indicators. The results reveal a nonlinear relationship between climate indicators and crop yields. Thresholds lead to a sharp decrease or increase in crop yields. Under SSP3‐7.0, rising temperatures tend to increase crop yield losses until 2100 without effective adaptation measures. The impact of changing soil moisture–related indicators depends on crop and country. Our study discusses adaptation strategies but also emphasizes the relevance of global mitigation efforts to reduce climate‐induced crop risk and to improve our food system's resilience.

Economic inequality expanded after an extreme climate event: a long-term analysis of herders’ household data in Mongolia

AbstractThe importance of ending poverty and reducing economic inequality has been explicitly recognized globally. Climate extremes are a critical global risk and can lead to economic damages, but empirical evidence of their effects on economic inequality is limited. Here, we focus on Mongolian pastoralism, which has a coupled socio-ecological system, to examine the trend of economic inequality among herders following a climate extreme event. Mongolia experienced a winter disaster in 2009 that caused a mortality of about 20% of the total number of livestock across the country. We used a long-term livestock panel dataset at the household level (n = 787) during 2004–2013 to examine changes in the economic distribution after the disaster. Economic inequality increased after the disaster (Gini coefficient increased from 0.46 to 0.61), and the increased level of inequality remained 4 years after the disaster. A decomposition of the inequality analysis showed that within-group inequality largely contributed to the greater total inequality, and household groups with a small number of livestock had the largest increase in inequality. Moreover, household groups that did not recover their livestock number had a higher loss rate of livestock during the disaster than household groups that did recover. Although the number of total livestock in the study area did recover after 4 years, we empirically showed that inequality among herders increased after the disaster. This result suggests that economic distributions are critical when examining the socio-economic impacts of climate extremes. We also suggest that preparing for disasters during normal years to alleviate loss of livestock during a disaster, especially for households with a small number of livestock, is a critical way to reduce poverty in the face of more frequent climate extremes.

The responses of ecological indicators to compound extreme climate indices in Southwestern China

Global warming has been leading to frequent climate extremes, and a single variable of climate extremes is no longer sufficient to fully assess the impact of climate extremes on ecosystems, requiring a synergistic multivariate inquiry. We obtain the compound warm-dry index (CWD) and the compound cold-dry index (CCD), based on a Copula theory with a binary distribution of a standardized precipitation index (SPI) and a standardized temperature index (STI). Changes in the spatial and temporal patterns of the compound extreme climate indices (CECIs) and the direct and lag responses of ecological indicators (EIs) to the CECIs in Southwestern China (SWC) are analyzed using these two indices. We find that CECIs rise continually during 1980–2019 (p < 0.05), with spring CCD being particularly pronounced (74.8 %, p < 0.01). Moreover, there are regional asymmetries and seasonal asymmetries in the direct and lag responses of ecosystems to compound extreme climate events (CECEs). CWD promotes productivity in spring and the response diminishes in summer, with the response area shifting towards higher altitudes. Spring CWD has a strong lag effect that will suppress summer productivity at higher elevation (>3000 m). Spring CCD promotes the growth of vegetation at low elevation (<1000 m), while summer CCD inhibits it at high elevation. Meanwhile, spring CCD has a strong lag positive effect on summer vegetation growth at low elevation specifically in Sichuan Basin, especially for crops (46.8 %). Our findings highlight the impact of compound climatic conditions on vegetation at specific geographical terrain, and vegetation in different regions can have complex and different responses to compound climate extremes.

270 Cellular Response to Heat Exposure: Influences on the Growth Potential of Bovine Skeletal Muscle and Adipose Tissue

Abstract Our lack of understanding regarding how heat exposure affects major tissue growth and meat attributes impedes our ability to counteract more frequent climate extremes and promote profitability in the beef cattle industry. The objective of the study was to determine pathways that heat shock proteins (HSPs) regulate in beef cattle’s skeletal muscle and adipose tissue growth and metabolism. Bovine satellite cells (BSCs) were isolated from the longissimus muscle of 3-month-old Holstein bulls (n = 5). Preadipose cells were isolated from the subcutaneous fat of 18-month-old Angus steers (n = 5) and induced adipogenic differentiation. Satellite, myofibers, and adipose cells were incubated at 38°C (control; CON), 39.5°C (moderate heat stress; MHS), and 41°C (extreme heat stress; EHS) and harvested for mRNA gene expressions, protein level, proteomics, immunostaining. Heat exposure cued bovine satellite cell proliferation and may increase the self-renewing satellite cell population. After 3 h of heat exposure, the mRNA gene expression and protein levels of Pax3 and Myf5 were downregulated, while HSPs 20, 27, 70, and 90 were upregulated. Small heat shock proteins, especially HSP27, appear to be essential in regulating satellite cell activity under heat stress. When HSP27 knock-down BSCs were exposed to EHS for 3 h, Myf5 gene expressions and protein levels returned to normal. This may indicate that HSP27 directly regulates Myf5 under heat stress and temporarily activates the self-renewal mechanism instead of committing myogenic differentiation. Results from proteomics showed that pathways related to oxidative phosphorylation, NADH dehydrogenase activity, and transmembrane transport were upregulated by EHS while MHS upregulated biosynthesis of amino acids, PI3K-Akt signaling pathway. Heat exposure during myogenic differentiation of satellite cells seemingly stimulates the commitment of myogenesis. Heat treatments increased mRNA gene expressions of IGF I, MHC I, MyoD, and myogenin and protein levels. Heat exposure also improved the muscle protein synthesis pathway by regulating the phosphorylation of mTOR, Akt, and P70S6. Heat stress triggered adipogenic differentiation and lipid storage, followed by increased expression of HSP. Extreme heat stress increased adipose cell growth by upregulating C/EBPα and PPARγ, key regulators of adipogenesis. Lipogenic genes FAS and SCD were also increased, accompanied by HSPs. Adipocytes exposed to EHS also increased intracellular lipid accumulation. Proteomic analysis revealed that carbon and pyruvate metabolism pathways were upregulated by MHS, whereas glycolysis/ gluconeogenesis, protein processing in the endoplasmic reticulum, RNA transport, and biosynthesis of amino acids were upregulated by EHS. Cellular mechanisms related to skeletal muscle hypertrophy and adipose tissue growth are responsive in in-vitro settings; however, the results are controversial depending on cell type and animal species. Various factors such as metabolic, hormonal, and immunologic regulation need to be considered to accurately assess the effect of HS on the postnatal growth of major tissues at the animal level.