Abstract

Theoretical models predict that, in the absence of moisture limitation, extreme precipitation intensity could exponentially increase with temperatures at a rate determined by the Clausius-Clapeyron (C-C) relationship(1,2). Climate models project a continuous increase of precipitation extremes for... Show moreTheoretical models predict that, in the absence of moisture limitation, extreme precipitation intensity could exponentially increase with temperatures at a rate determined by the Clausius-Clapeyron (C-C) relationship(1,2). Climate models project a continuous increase of precipitation extremes for the twenty-first century over most of the globe(3-5). However, some station observations suggest a negative scaling of extreme precipitation with very high temperatures(6-9), raising doubts about future increase of precipitation extremes. Here we show for the present-day climate over most of the globe, the curve relating daily precipitation extremes with local temperatures has a peak structure, increasing as expected at the low-medium range of temperature variations but decreasing at high temperatures. However, this peak-shaped relationship does not imply a potential upper limit for future precipitation extremes. Climate models project both the peak of extreme precipitation and the temperature at which it peaks (T-peak) will increase with warming; the two increases generally conform to the C-C scaling rate in mid-and high-latitudes, and to a super C-C scaling in most of the tropics. Because projected increases of local mean temperature (T-mean) far exceed projected increases of T-peak over land, the conventional approach of relating extreme precipitation to Tmean produces a misleading sub-C-C scaling rate. Show less