快猫短视频

Be prepared for even more extreme rainfall events and flooding as the world warms. A study comparing what has happened so far with what climate models project has found that extreme events are happening around 50 per cent more often than predicted. This means that the climate models are also underestimating how much worse these events will become in the future.

鈥淓xtremes appear to intensify faster with global warming than the models predict,鈥� says team member at the Potsdam Institute of Climate Impact Research in Germany. 鈥淓xtreme rainfall will be heavier and more frequent. Society needs to be prepared for this.鈥�

More extreme rainfall as a result of global heating is already causing ever more disasters around the world, from Hurricane Harvey in 2017 dumping more than a metre of rain on Houston, Texas, to extreme monsoon rains in 2022 that caused widespread floods in Pakistan.

The fundamental reason why is that as the atmosphere warms, it can hold more moisture, meaning more rain 鈥撀�or snow or hail 鈥� can fall. But how much more?

Levermann and his colleagues analysed historical records of weather events to see how extreme rainfall events have changed so far. They used a pattern recognition method to try to distinguish between changes due to human influence and those caused by random fluctuations in the climate.

The researchers then compared their findings with the projections of the widely used CMIP-6 climate models. Among other things, they found that the frequency of extreme events has increased by 17 per cent per degree Celsius of warming, whereas the climate models project only an 11 per cent increase.

鈥淭he intensification of heavy precipitation extremes that we鈥檝e seen in the historical data is quite a lot stronger than what most of the physical climate models are projecting,鈥� says team member also at the Potsdam institute. 鈥淭here鈥檚 no reason to think that that鈥檚 not going to continue.鈥�

This isn鈥檛 an entirely new issue, he says. A similar problem was seen with an earlier generation of climate models around a decade ago, but this study shows the latest models still aren鈥檛 getting it right.

Part of the problem is the low resolution of global climate models, says Levermann. 鈥淭he models are not built for modelling extreme weather events, since they average over large areas and long times.鈥�

鈥淭he authors show that many global climate models appear to underestimate the observed rate of exponential increase,鈥� says at the Met Office Hadley Centre in the UK. 鈥淭his is quite plausible given that many of the global climate models do not have sufficient spatial resolution to fully resolve the processes in clouds that can lead to very heavy rainfall.鈥�

Some researchers have created higher-resolution models that can simulate processes in clouds more accurately, and these models do show faster increases in very intense rainfall than the global models, says Stott.

鈥淎s the authors state, societies need to be prepared for the increases in heavy rainfall and flooding coming our way,鈥� he says.

have also found that the current generation of global climate models are underestimating some weather extremes, such as summer flooding, says at the University of Pennsylvania. 鈥淚t鈥檚 consistent with our own published and ongoing work.鈥�