Drought is one of the most damaging types of extreme climate. Meanwhile, drought events have become more frequent and intense due to global warming. Understanding how droughts in arid regions respond to global warming, as well as producing reliable projections of their future changes and related risks, is essential to facilitate mitigation for climate change.
Both the attribution of historical changes in drought and future projections of droughts rely heavily on climate modeling. However, reasonable drought simulations have remained a challenge.
Researchers from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences have examined how current state-of-the-art climate models perform in simulating drought in arid regions.
"Our results confirm the capability of the latest climate models in capturing primary characteristics of drought-related meteorological elements," said YU Xiaojing, first author of the study. Nevertheless, the team also noticed that the long-term water deficit condition over arid regions in the examined models was underestimated, due to a larger water supply (precipitation) but weaker atmospheric water demand (potential evapotranspiration).
Observations revealed a significant increase in drought risk in arid regions since the 1980s, because there had been a more widespread drought-affected area and a higher occurrence of drought. YU noted that state-of-the-art climate models were capable of reproducing the observed increasing trends in drought events and corresponding meteorological anomalies. However, the simulated changes in drought after the late 1990s were obviously underestimated. This indicates a weaker-than-observed response of drought in arid regions to global warming in current models.
"Our results have important implications for the application of the latest climate models in studies related to drought in arid regions. It is imperative to employ bias-correction approaches when using the outputs of these models to investigate the impacts of drought in arid ecosystems," said associate professor ZHANG Lixia, corresponding author of the study.