Climate Change Linked To Devastating Texas Floods

http://thinkprogress.org/climate/2015/08/13/3691423/study-manmade-climate-change-texas-floods/

by Joe Romm Aug 13, 2015

A new study directly links human-caused global warming to the catastrophic flooding in Texas and Oklahoma this spring.

In May, more than 35 trillion gallons of water fell on Texas — enough to cover the entire state in eight inches of water. More than two dozen people were killed, and it was the wettest single month on record in both Texas and Oklahoma.

A new peer-reviewed study from Utah State and Taiwanese researchers concluded, “There was a detectable effect of anthropogenic [manmade] global warming in the physical processes that caused the persistent precipitation in May of 2015″ over the southern Great Plains.”

We’ve known for a long time that global warming puts more moisture in the atmosphere, which in turn makes deluges more intense. And the 2014 U.S. National Climate Assessment found that Texas and Oklahoma — and indeed most parts of the country — have already seen an measurable increase in the most intense rain storms.

But the Geophysical Research Letters study found a much deeper link between human-caused climate change and the Texas floods. I asked the study’s lead author, Simon Wang of the Utah Climate Center, to explain the findings:

Basically, we linked the weather conditions that caused the consecutive and high amounts of rainfall to two main climate sources: (1) El Niño and its enhanced teleconnection owing to the warming Pacific temperature [and this El Niño is strengthened by global warming] and (2) middle latitude circulation that is becoming increasingly “wavy,” causing the trough (or any ridge for that regard) to stick around for a long time.

The second conclusion — that climate change is causing weather patterns to stall — joins a growing body of research tying the recent jump in extreme weather to a warming-driven weakening of the jet stream and “more frequent high-amplitude (wavy) jet-stream configurations that favor persistent weather patterns,” as a January 2015 study put it.

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