Changes of extreme climate events and related risk exposures inHuang-Huai-Hairiver basin under 1.5-2 degrees C global warming targets based on high resolution combined dynamical and statistical downscaling dataset

摘要

Extreme climate events and related risk exposures in Huang-Huai-Hai (HHH) river basin were projected under global warming of 1.5-2 degrees C using the high-resolution combined dynamical and statistical downscaling dataset. Firstly, evaluation indicated that the dataset can well reproduce the spatial distribution of all temperature extremes and most of the precipitation extremes, providing a reliable ability for future projections. Then, projections showed that the hot events were projected to increase, while the cold events were projected to decrease substantially in the whole HHH river basin for 1.5 degrees C and 2 degrees C global warming. The additional 0.5 degrees C of warming roughly accelerated the increase of extreme temperatures by 0.6 degrees C, and increased the number of heat days by 2.7 days. In addition, the rainfall events and the precipitation intensity were projected to increase while the drought events were projected to decrease, with the slight changes due to the additional 0.5 degrees C warming. The gross domestic product (GDP) exposures to heat events and heavy rainfall increased more than nine fold for 1.5 degrees C and 2 degrees C global warming, while the growing population (POP) exposures to that increased by more than 100% and 20%, respectively. For the increased exposures to heat events, the changes in GDP (POP) were as important as changes in interaction effect between climate and GDP (POP), while the exposures to heavy rainfall events was mainly dominated by GDP (POP). In addition, the enhanced interaction effect was the most important factor to the increase of exposures due to additional 0.5 degrees C of warming. Notably, the largest increases of heat events and heavy rainfall events were projected in Huaihe river basin due to the additional 0.5 degrees C warming, accompanied by greatest increase of exposures, implying larger risk in the future.