Characteristics of Spatial and Temporal Variations of Global Terrestrial Droughts and Analysis of their Future Trends
Online published: 2025-02-24
Drought represents a significant contributing factor to global climate-related disasters. It not only endangers the stability of global ecosystems and biodiversity but also has far-reaching implications for socio-eco‐ nomic development. As global climate change intensifies,so too does the frequency and intensity of droughts. Drought events in ecologically fragile regions not only threaten the availability of water resources but also in‐ crease the risk of food insecurity,ecological degradation and social conflict. Nevertheless,despite the growing body of research in this area,there remain significant gaps in our understanding of the spatial and temporal characteristics of drought occurrences over the past four decades,as well as its evolutionary trends under different cli‐ mate scenarios in the future. This study employs the Standardized Precipitation Evapotranspiration Index(SPEI) and CMIP6 climate change scenarios to analyze the spatial and temporal characteristics of global droughts over the past four decades and to predict the evolution of global droughts under different climate scenarios(SSP1- 2. 6、SSP2-4. 5、SSP5-8. 5)over the next 80 years. The findings of the study indicate that:(1)During the peri‐ od between 1980 and 2022,there were notable variations in the spatial and temporal characteristics of global drought across different regions. Globally,approximately 57% of the land area does not exhibit a significant drought trend. However,about 33% of the land shows a persistent aridification trend,particularly in some al‐ ready arid regions,where the intensity of drought has increased. Conversely,only 10% of the area is becoming wetter,indicating that the regions of the globe that are becoming drier are significantly larger than those that are becoming wetter. This suggests that the aridification process is spreading globally;(2)Over the past four de‐ cades,the globe has experienced an arid trend with no significant seasonal differences. However,the arid regions in winter are expanding,accounting for 33. 2% of the global land area;(3)Different vegetation cover types exhibit varying responses to drought. Sparsely vegetated areas are more susceptible to drought,while densely vegetated areas tend to be wetter. Furthermore,arid climate zones situated within diverse climatic contexts are confronted with more pronounced drought-related challenges. The largest proportion of severe drought is observed in extreme arid zones,which account for up to 67% of the global land area,this indicates a higher frequency of drought events in drylands;(4)The probability of drought events is predicted to increase significantly in Africa,South America,southeastern Asia,and southern North America,particularly in tropical or warm climatic zones,extreme arid zones,and evergreen broadleaf climate zones. Furthermore,droughts are expected to become more frequent and severe,especially in tropical or very warm climate zones,arid zones,and broadleaf evergreen forest regions. The SSP5-8. 5 scenario is projected to have the highest probability and intensity of drought events over the next 80 years,and will be challenged by more frequent and severe droughts. The findings of this study underscore the pervasive and severe nature of the global aridification trend,particularly in the context of climate change,where the frequency and intensity of droughts are projected to increase significantly. This trend not only enhances our comprehension of the risk of drought,but also furnishes an essential point of reference for policymakers,water managers,and the general public. In order to mitigate the potential intensification of droughts in the future,it is imperative that all sectors of society implement more proactive and efficacious measures to promote adaptation and mitigate the challenges posed by droughts. The rational management of water resources,improvements in agricultural irrigation techniques,enhanced ecosystem resilience and the strengthening of monitoring and early warning systems for climate change and droughts will ensure global eco‐ logical security and facilitate sustainable socio-economic development.
Key words:
global drought; SPEI; spatiotemporal changes; Mann-Kendall test; CMIP6
XU Xinyao, WANG Xufeng, ZHANG Songlin, YANG Yanpeng, LI Zongxing . Characteristics of Spatial and Temporal Variations of Global Terrestrial Droughts and Analysis of their Future Trends[J]. Plateau Meteorology, 0 : 1 . DOI: 10. 7522/j. issn. 1000- 0534. 2024. 00109
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