Climate change is exacerbating the global water cycle


Human-induced climate change is warming the planet, which in turn enables our atmosphere to hold more water. The magnitude and magnitude of this transition is challenging globally, but its impact on local weather is more pronounced: increased evaporation in some regions and increased precipitation in others has led to more frequent and intense droughts and rainfall – With the looming risk of more extreme weather events in the near future.

“In recent years, we have continued to experience unprecedented flooding, with large volumes of water rushing through the climate system,” said Paul Dulac, a climate scientist at Lawrence Livermore National Laboratory in California. “This changing condition is linked to a warming atmosphere and a The turbo water cycle is consistent.”

But it’s not easy to determine how much the global water cycle has intensified. Evaporation rates are difficult to measure, and estimates of precipitation are equally challenging unless the entire planet is covered with rain gauges. To solve this problem, climate scientists turned to the oceans, where most of the Earth’s evaporation and precipitation occurs.

“We were able to determine how much the water cycle has changed based on observations of ocean salinity,” said Taimoor Sohail, a climate scientist at the University of New South Wales in Sydney.

in a new research, he and a team of researchers studied changes in the world’s ocean salinity, explaining mixing and ocean currents. They found that since 1970, water near Earth’s subtropics, such as the southeastern United States, has become saltier due to increased evaporation. Due to increased precipitation, the water near the polar regions has become less salty. “It’s like you put a bowl of salt water outside in the sun, and the fresh water evaporates, leaving behind the salt,” Sohail explained.

The results show that the water cycle has intensified, with more evaporative water transported from warm, dry regions to higher latitudes, falling as rain or snow. “The change in salinity confirms that wetter regions are getting wetter,” Dulac said. “This means that areas of the ocean that are fresh are getting fresher, and drier parts of the ocean that are already salty are getting drier or saltier.”

This result is consistent with the first study of ocean salinity and the water cycle, post as early as 2003, and subsequent work—including 2012 Research Based on changes in ocean salinity between 1950 and 2009, the water cycle intensified by 8 percent, according to the report, led by Durack.

“Each study took a slightly different approach, but we got more or less very consistent intensification – about 7 percent per degree Celsius [of global warming],” Dulac said. “This latest study reaffirms the growing consensus. “

Changes in salinity observed over the past few decades also suggest that the water cycle is more intense than current climate models predict. “We’re pushing to double the intensity of climate model estimates,” Sohail explained. “This should be seen as an impetus to accelerate mitigation and adaptation to climate change, especially changes in extreme rainfall and evaporation.”

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