Key Takeaways<\/h4>\n\n\n\n\n- During extreme weather events, mountains will see more water fall as rain instead of as snow \u2013 making them vulnerable to floods, landslides, and soil erosion.<\/li>\n\n\n\n
- For every 1 degree Celsius of global warming, researchers expect an average of 15% more rain at high elevations.<\/li>\n\n\n\n
- The North American Pacific mountain ranges (Cascades, Sierra Nevada, and coastal ranges), Himalayas, and high-latitude regions are most at risk.<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n
As the world warms, extreme weather events grow \u2013 and they also change. Researchers at the Department of Energy\u2019s Lawrence Berkeley National Laboratory (Berkeley Lab) found that climate change is shifting snowfall to rainfall on mountains across the Northern Hemisphere. Those surges of liquid water bring a distinct set of dangers, including floods, landslides, and soil erosion.<\/p>\n\n\n\n
\u201cOne quarter of the global population lives in or downstream from mountainous regions,\u201d said Mohammed Ombadi, first author of the paper published today in Nature<\/em><\/a>. \u201cThey are going to be directly affected by this risk.\u201d<\/p>\n\n\n\nScientists already expect climate change to increase the volume of water falling during extreme events (which typically take place over a few hours to a day), but this study is the first time researchers have looked at whether that extreme precipitation comes as rain or snow. They found that the fraction of water falling as snow decreased in mountainous regions, falling instead as rain \u2013 making mountains particularly susceptible to extreme rain hazards. They even put a number to it: For every 1 degree Celsius increase in the global temperature, researchers expect an average of 15% more rain at high elevations.<\/p>\n\n\n\n
\u201cThis increase in rainfall extremes is not only something that is going to happen from now until the end of the 21st century \u2013 we\u2019re already seeing it,\u201d Ombadi said. \u201cThat same rate was also evident in the data from 1950 to 2019. Rainfall extremes in mountains have already been increasing, and will continue to change with that 15% rate.\u201d<\/p>\n\n\n\n
While all the mountain ranges in the Northern Hemisphere are seeing the shift from snow to rain, those at greatest risk of extreme rainfall events are the North American Pacific mountain ranges (the Cascades, Sierra Nevada, and coastal ranges from Canada to Southern California), the Himalayas, and high-latitude regions. Researchers will need to conduct more work to understand why certain regions are at higher risk than others.<\/p>\n\n\n
\n![\"\"](\"https:\/\/www.sonnenseite.com\/wp-content\/uploads\/2023\/06\/BerkeleyLab_MohammedOmbadi.jpg\")
<\/a>This map shows the projected risk of rainfall extremes by the end of this century. Areas in the darkest blue are 8 times more likely to experience an extreme rainfall event (compared to 1950-1979). Mountainous (high-elevation) and northerly (high-latitude) regions are at the greatest risk. (Credit: Mohammed Ombadi\/Berkeley Lab)<\/figcaption><\/figure>\n<\/div>\n\n\n\u201cWe think that North American Pacific mountain ranges are more susceptible to the risk of rainfall extremes than other mountain ranges because a significant portion of snowfall in this region typically occurs at temperatures just below zero degrees Celsius,\u201d Ombadi said. \u201cThe slightest change in air temperature will shift this snowfall to rainfall. This is unlike other mountain ranges where snowfall may occur at very low temperatures below zero degrees.\u201d<\/p>\n\n\n\n
Ombadi hopes that fellow climate scientists will incorporate the distinction between snowfall and rainfall to improve global climate models<\/a>, and that civil engineers and planners will use the data to better prepare for intense rain events.<\/p>\n\n\n\n\u201cWe need to factor these results into how we design and build the infrastructure in these mountainous regions, so that they can withstand the negative consequences of increases in rainfall extremes,\u201d Ombadi said.<\/p>\n\n\n\n
Meanwhile, countries continue efforts to meet targets established by the Paris Agreement<\/a> that would limit global warming to less than 2 degrees Celsius above pre-industrial levels.<\/p>\n\n\n\n\u201cOur findings revealed a linear relationship between the level of warming and the increase in extreme rainfall: For instance, 1 degree of warming causes 15% more rain, while 3 degrees leads to a 45% increase in rainfall,\u201d Ombadi said. \u201cThere are many technologies in progress that could help us reduce greenhouse gas emissions and how much the planet warms. To me, this study shows the need to invest in those clean solutions, and also start preparing for the consequences of warming now.\u201d<\/p>\n\n\n\n
This work was funded by the DOE Office of Science Biological and Environmental Research program, both through CASCADE<\/a> (Calibrated and Systematic Characterization, Attribution, and Detection of Extremes) and iNAIADS<\/a> (iNtegration, Artificial Intelligence and Analytical Data Services), a DOE Early Career Research Award.<\/p>\n\n\n\n
As the world warms, extreme weather events grow \u2013 and they also change. Researchers at the Department of Energy\u2019s Lawrence Berkeley National Laboratory (Berkeley Lab) found that climate change is shifting snowfall to rainfall on mountains across the Northern Hemisphere. Those surges of liquid water bring a distinct set of dangers, including floods, landslides, and soil erosion.<\/p>\n\n\n\n
\u201cOne quarter of the global population lives in or downstream from mountainous regions,\u201d said Mohammed Ombadi, first author of the paper published today in Nature<\/em><\/a>. \u201cThey are going to be directly affected by this risk.\u201d<\/p>\n\n\n\n Scientists already expect climate change to increase the volume of water falling during extreme events (which typically take place over a few hours to a day), but this study is the first time researchers have looked at whether that extreme precipitation comes as rain or snow. They found that the fraction of water falling as snow decreased in mountainous regions, falling instead as rain \u2013 making mountains particularly susceptible to extreme rain hazards. They even put a number to it: For every 1 degree Celsius increase in the global temperature, researchers expect an average of 15% more rain at high elevations.<\/p>\n\n\n\n \u201cThis increase in rainfall extremes is not only something that is going to happen from now until the end of the 21st century \u2013 we\u2019re already seeing it,\u201d Ombadi said. \u201cThat same rate was also evident in the data from 1950 to 2019. Rainfall extremes in mountains have already been increasing, and will continue to change with that 15% rate.\u201d<\/p>\n\n\n\n While all the mountain ranges in the Northern Hemisphere are seeing the shift from snow to rain, those at greatest risk of extreme rainfall events are the North American Pacific mountain ranges (the Cascades, Sierra Nevada, and coastal ranges from Canada to Southern California), the Himalayas, and high-latitude regions. Researchers will need to conduct more work to understand why certain regions are at higher risk than others.<\/p>\n\n\n \u201cWe think that North American Pacific mountain ranges are more susceptible to the risk of rainfall extremes than other mountain ranges because a significant portion of snowfall in this region typically occurs at temperatures just below zero degrees Celsius,\u201d Ombadi said. \u201cThe slightest change in air temperature will shift this snowfall to rainfall. This is unlike other mountain ranges where snowfall may occur at very low temperatures below zero degrees.\u201d<\/p>\n\n\n\n Ombadi hopes that fellow climate scientists will incorporate the distinction between snowfall and rainfall to improve global climate models<\/a>, and that civil engineers and planners will use the data to better prepare for intense rain events.<\/p>\n\n\n\n \u201cWe need to factor these results into how we design and build the infrastructure in these mountainous regions, so that they can withstand the negative consequences of increases in rainfall extremes,\u201d Ombadi said.<\/p>\n\n\n\n Meanwhile, countries continue efforts to meet targets established by the Paris Agreement<\/a> that would limit global warming to less than 2 degrees Celsius above pre-industrial levels.<\/p>\n\n\n\n \u201cOur findings revealed a linear relationship between the level of warming and the increase in extreme rainfall: For instance, 1 degree of warming causes 15% more rain, while 3 degrees leads to a 45% increase in rainfall,\u201d Ombadi said. \u201cThere are many technologies in progress that could help us reduce greenhouse gas emissions and how much the planet warms. To me, this study shows the need to invest in those clean solutions, and also start preparing for the consequences of warming now.\u201d<\/p>\n\n\n\n This work was funded by the DOE Office of Science Biological and Environmental Research program, both through CASCADE<\/a> (Calibrated and Systematic Characterization, Attribution, and Detection of Extremes) and iNAIADS<\/a> (iNtegration, Artificial Intelligence and Analytical Data Services), a DOE Early Career Research Award.<\/p>\n\n\n\n<\/a>