Global warming increases more extreme precipitation than expected – sunny side up

One piece of evidence shows that the intensity and frequency of extreme precipitation is increasing dramatically with global warming New study Potsdam Institute for Climate Impact Research (PIK).

The researchers also found that climate models significantly underestimate the increase in the frequency of extreme precipitation. Heavy rain events are increasing faster than climate models previously suggested.

“Our study confirms that the intensity and frequency of heavy rainfall increases dramatically with every degree of global warming,” explains Max Kutz, lead author of the study published in the journal Climate. These changes follow the physical law of the 1834 Clausius-Clapeyron equation, which states that warmer air can hold more water vapor. “Current climate models vary in how much precipitation will increase dramatically with global warming, and they underestimate this increase compared to historical observational data.”

“The effects of global warming on our lives have been calculated based on climate models. Our results suggest that climate impacts may be worse than we thought. Heavy rains will become heavier and more frequent. As a society, we must We adapt to this.” Changes in the frequency and intensity of extreme daily rainfall on land can impact the prosperity and stability of a community as well as economic development. Floods, as well as the availability of groundwater, can lead not only to financial losses, but also to significant loss of life. .

PIK researchers analyzed the intensity and frequency of extreme daily precipitation over Earth in 21 latest-generation climate simulations (CMIP-6) and compared them with historical observations. The pattern recognition method they use allows them to distinguish between changes in the climate system that are caused by human emissions and those that are not.

While the intensity and frequency of extreme events are increasing in most land areas, larger increases are typically expected in tropical regions, according to the study. Significant changes occur most often in the tropics and high latitudes, such as Southeast Asia or northern Canada. The fact that these changes follow the Clausius-Clapeyron equation highlights that changes in extreme precipitation around the world are driven by thermodynamic variables such as temperature, rather than dynamic forcings such as wind. “The good news is that this makes heavy rainfall more predictable in the future. The bad news is that heavy rainfall will continue to become more frequent and intense as long as we continue to increase global temperatures by emitting greenhouse gases,” adds Anders Levermann. .

• Maximilian Kutz, Stefan Lange, Leonie Wiens, Anders Levermann (2023): Constraining the pattern and magnitude of projected extreme precipitation change in a multi-model ensemble [DOI: 10.1175/JCLI-D-23-0492.1]

source

Potsdam Institute for Climate Impact Research (PIK) 2023