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Abstract:
Of rising concern is the consecutive occurrence of contrasting precipitation extremes such as droughts followed by severe floods, which tips a precarious balance with lasting impacts on human and natural systems. However, it is not clear how the risk of such precipitation reversals may change over time at the global scale. Using precipitation data from the Community Earth System Model Version 1 (CESM1) Large Ensemble Simulations (LENS), we examined changes in the likelihood and spatial distribution of low‐intensity dry‐to‐wet fluctuations and more severe shifts from meteorological droughts to pluvials over global land areas via a conditional statistical framework. Our analysis of CESM1‐LENS leads to the conclusion that the worst‐case climate change scenario, that is, RCP8.5 can increase the percent of global land areas susceptible to both low‐intensity and more severe precipitation reversals by the end of the twenty‐first century, while inducing disproportionate impacts at regional scales depending on the severity of precipitation reversals. Particularly, we find 13.6% of global land areas may be depressed by interannual dry‐to‐wet events with a transition probability of greater than 0.5 in the twenty‐first century, quintupling the figure in the past century. The increase in the susceptible global land areas further indicates that new local hotspots with low‐frequency drought‐pluvial seesaws are more likely to emerge under the effects of enhancing anthropogenic greenhouse gases. Collectively, the study is expected to provide useful information for policy makers and infrastructure operators to prioritize actions that affect water resource objectives of flood control, drought mitigation, and water quality protection.
