Flood fears surge amid new study in moisture retention levels

As delegates head for Dubai for the COP28 Summit later this week a new study has warned that the global warming will intensify heavy rain beyond current expectations significantly enhancing the threat of future flood risks.

The research from a team at the Potsdam Institute for Climate Impact research (PIK) warns that tropical regions across the world are at most risk but that there is no area of the planet which may bot feel the impact of the changing climate.

“Our study confirms that the intensity and frequency of heavy rainfall extremes are increasing exponentially with every increment of global warming,” explained Max Kotz, lead-author of the study.

The study found that the changes follow the physical theory of the classic Clausius-Clapeyron relation of 1834, which established that warmer air can hold more water vapour. ”State-of-the-art climate models vary on how strongly extreme rainfall scales with global warming and that they underestimate it compared to historical observations,” he added.
“Climate impacts on society have been calculated using climate models. Now our findings suggest that these impacts could be much worse than we thought. Extreme rainfall will be heavier and more frequent. Society needs to be prepared for this,” says PIK department head and author of the study Anders Levermann.

The research warned changes in the frequency and intensity of daily rainfall extremes over land can impact social welfare, the economy and social stability, given their link to flooding but also ground-water availability, which can cause considerable loss of life and financial losses.
The researchers at PIK analysed the intensity and frequency of daily precipitation extremes over land in 21 state-of-the-art climate simulations (CMIP-6) and compared the changes projected by CMIP-6 models to those observed historically. The method they applied draws on pattern-filtering techniques, allowing them to separate which changes in the climate system are forced by human emissions, and which are not.
The study concluded: “While most land-areas exhibit increases in both the intensity and frequency of extremes, stronger increases are typically found across tropical regions, according to the study.

“Significant changes most often occur across the tropics and high latitudes, like in Southeast Asia or Northern Canada. The fact that these changes follow the Clausius-Clapeyron relation underpins the fact that thermodynamics, i.e. temperature and not dynamics, i.e. winds, dominate the global change of extreme rainfall events.”

“The good news is that this makes it easier to predict the future of extreme rainfall. The bad news is: It will get worse, if we keep pushing up global temperatures by emitting greenhouse gases,” Levermann added.

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