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Grim drought outlook for western US offers warnings for the future

Phys.org/news (MAY 20, 2022)

Titre : Grim drought outlook for western US offers warnings for the future

Much of the western U.S. has been in the grip of an unrelenting drought since early 2020. The dryness has coincided with record-breaking wildfires, intense and long-lasting heat waves, low stream flows and dwindling water supplies in reservoirs that millions of people across the region rely on.

Phys.org/news (MAY 20, 2022)

Présentation
Heading into summer, the outlook is pretty grim. The National Weather Service’s latest seasonal outlook, issued May 19, 2022, described drought persisting across most of the West and parts of the Great Plains.

One driver of the Western drought has been persistent La Niña conditions in the tropical Pacific since the summer of 2020. During La Niña, cooler tropical Pacific waters help nudge the jet stream northward. That tends to bring fewer storms to the southern tier of the U.S. and produce pronounced drought impacts in the Southwest.

The other and perhaps more important part of the story is the hotter and thirstier atmosphere, caused by a rapidly warming climate.

As a climate scientist, I’ve watched how climate change is making drought conditions increasingly worse—particularly in the western and central U.S. The last two years have been more than 2 degrees Fahrenheit (1.1 Celsius) warmer than normal in these regions. Large swaths of the Southwest have been even hotter, with temperatures more than 3 F (1.7 C) higher. Studies suggest the Southwest’s ongoing 20-year drought is the most severe in at least 1,200 years, based on how dry the soils are.

Source  : Imtiaz Rangwala, The Conversation

Annonce (Phys.org/news)

Page publiée le 16 janvier 2023