With global warming, extreme rainfall at high altitudes is becoming even more likely in regions previously more used to snowfall, researchers conclude in a paper published in Nature on Wednesday that advocates “robust” adaptation strategies.
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A team of US scientists studied the impact of climate change on precipitation patterns, using observational data for the period 1950-2019 and forecasts for the coming years.
In particular, they focused on the high-altitude regions (above 2,000 meters) where snowfall is present today, which will tend to turn to rain in a warming climate.
While it is already known that warming increases extreme precipitation (rain or snow), the study focuses more specifically on precipitation. Because these would not have the same consequences as snowfall, the authors point out.
“It’s important to monitor the rains because they have devastating effects on flooding, landslides and soil erosion,” lead author Mohammed Ombadi of Lawrence Berkeley National Laboratory in California told AFP. about the study.
The main conclusion of this research: “The increase in extreme precipitation in the high mountain regions of the Northern Hemisphere is amplified at an average of 15% per degree of warming,” almost twice that expected in the lowlands, the authors conclude.
“Our results suggest that high-altitude regions are vulnerable hotspots for future extreme rainfall risks that require robust adaptation plans,” they add.
“You cannot design infrastructure based on past conditions if you want to ensure that it will remain sustainable in a warmer climate,” stresses Mohammed Ombadi.
Specifically, he suggests taking into account the increase in extreme rainfall in the planning and construction of infrastructure (dams, roads, railways) or even refining the risk assessment of landslides.
The risk affects not only the mountains, but also the downstream regions, where a quarter of humanity lives.
The recent floods in the western United States, or last year’s historic floods in Pakistan, “could be partly due to extreme rains that intensified at high altitudes,” combined with other factors, says Mohammed Ombadi.