Climate Change Has Helped Fuel a Megadrought in the Southwest USA
A “megadrought” gripping the western United States is the worst one in 500 years, scientists say. And it’s the first to be influenced by human-caused climate change.
According to the tree ring data, which extend back to A.D. 800, there have been a handful of extreme megadroughts over the last 1,200 years. The most recent one is happening right now. It’s gripping a wide swath of the southwestern United States and northern Mexico, and it’s been ongoing since around 2000.
The severity of the current megadrought is second only to the last event, which occurred in the late 1500s, the research say. It also seems to be happening for different reasons.
Past megadroughts were triggered by natural fluctuations in the Earth’s climate. Temporary shifts in the temperature of the Pacific Ocean, for instance, can have a strong influence on climate in the southwestern United States.
The researchers used a suite of climate models to investigate the influence of anthropogenic warming on the present-day situation. The models suggest that the warmer and drier conditions brought by climate change account for nearly half the severity of the current drought.
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