Human-driven climate change has already made our planet rainier, snowier, and more potentially dangerous, according to a new study.
As reported in the journal Nature Communications, earth scientists at the University of California, Los Angeles have used machine learning methods to show human-driven climate change has already driven an intensification in extreme precipitation events, both rain and snow, in recent decades. Left unchecked, it’s also likely that human activity will continue to contribute to extreme wet weather events in the future.
Scientists have long been concerned about how rising temperatures will intensify heavy precipitation events around the world. As the world warms, more water evaporates from oceans, lakes, and soils and ends up in Earth's atmosphere. A warmer atmosphere can also hold more moisture, with global water vapor increasing by around 7 percent for every 1°C of warming. So, when weather patterns call for rain or snow, there is even more moisture available for heavier downpours.
This doesn’t just mean climate change is causing more gray skies and rainy days, although that might be one aspect of the problem. As other studies have hinted, the intensification of precipitation also has the very real potential to increase the frequency or severity of landslide activity and flooding, which could cost lives.
Just this week, heavy rainfall triggered a landslide in the Japanese seaside city of Atami, killing two people and leaving 20 others missing. It’s too early to say how tightly this catastrophe was linked to climate change, but it’s clear this kind of event has been made more likely by global warming and increased rainfall.
Researchers have previously tried to understand how much climate change has influenced precipitation, but using the observational data is challenging due to natural variability and limited observations. To overcome this issue, the new study employs the help of machine learning that can account for these issues. With this aid, they found the clear influence of human-driven climate change was detectable in all global observational datasets.
“Machine learning efficiently generates multiple lines of evidence supporting detection of an anthropogenic signal in global extreme precipitation,” the study reads.
Some of the areas with the most obvious influence of climate change affecting precipitation were the East Asian and African monsoon regions, as well as the North Pacific and Atlantic storm track. On the other hand, no influence of climate change on precipitation was found in arid and semi-arid subtropical zones such as Northern African and Middle Eastern deserts, Southern South Africa, Australian arid and semi-arid regions, as well as wet regions such as central and northwestern parts of South America.
As this suggests, the changes in precipitation won't be uniform across the planet and some regions are set to experience more intense and longer droughts.