High Sensitivity of Compound Drought and Heatwave Events to Global
Warming in the Future
Abstract
Compound drought and heatwave (CDHW) events have received considerable
attention in recent years due to their devastating effects on human
society and ecosystem. In this study, we systematically investigated the
spatiotemporal changes of CDHW events for historical period (1951-2014)
and four future scenarios (2020-2100) (SSP1-2.6, SSP2-4.5, SSP3-7.0, and
SSP5-8.5) over global land by using Coupled Model Intercomparison
Project Phase 6 (CMIP6) models. The sensitivity of the CDHW events to
the changes of maximum air temperature and the climatic water balance
variables are also examined. The CDHW is defined by integrating monthly
standardized precipitation evapotranspiration index (SPEI) and daily
maximum temperatures. The results show that the multi-model ensembles
project a strong increasing trend in CDHW characteristics over almost
all global lands under SSP2-4.5, SSP3-7.0, and SSP5-8.5. A significant
increase in CDHW risk will witness across global land areas for the
medium to long term future, if there is not aggressive adaptation and
mitigation strategies. The results of sensitivity analysis suggest that
higher sensitivity of CDHW events to global warming will occur in the
future except SSP1-2.6. Particularly, each 1°C global warming increases
the duration of the CDHW events by 3 days in the historical period, but
by about 10 days in the future period. Overall, this study improves our
understanding in the projection of CDHW events and the impacts of
climate drivers to the CDHW events under various future scenarios, which
could provide support about the risk assessment, adaptation and
mitigation strategies under climate change.