美國西南部可能會在本世紀迎來“超級颶風”

美國西南部可能會在本世紀迎來“超級颶風”

The Southwestern U.S. is no stranger to droughts, but it may soon dry out more than it has in thousands of years. Thanks to man-made climate change, the region's chances of a decade-long drought are now at least 50 percent, according to a study, while its odds of a "megadrought" — which can last more than three decades — range from 20 to 50 percent over the next century.

美國西南部對干旱并不陌生，但它可能很快就會比幾千年來干旱得更多。據(jù)一項研究顯示，由于人為造成的氣候變化，該地區(qū)10年干旱的可能性現(xiàn)在至少為50%，而其“大干旱”(可能持續(xù)30多年)的可能性在下個世紀從20%到50%不等。

A boat navigates Lake Powell during a severe drought in March 2015 in Page, Arizona. (Photo: Justin Sullivan/Getty Images)

A more recent study reached the same conclusion but tried to answer bigger questions: What causes megadroughts and what factors control their timing? Lead author Nathan Steiger and colleagues at Columbia’s Earth Institute looked at climate models to find out why the 9th to 16th centuries experienced such droughts, but not since. They found that cooling ocean surface temperatures in the Pacific, warming surface temperatures in the Atlantic and "radiative forcing" were the causes.

最近的一項研究也得出了同樣的結論，但試圖回答更大的問題:是什么導致了特大光以及什么因素控制了它們的出現(xiàn)時間?研究報告的主要作者內(nèi)森·斯泰格爾和哥倫比亞大學地球研究所的同事們研究了氣候模型，以找出為什么9世紀至16世紀經(jīng)歷了這樣的干旱，但從那以后就沒有了。他們發(fā)現(xiàn)，太平洋海洋表面溫度的下降、大西洋表面溫度的上升和“輻射強迫”是原因。

That science matters because it offers a clear warning for today, when global warming is increasing and these same ocean temperature patterns are occurring. Their work was published in Science Advances.

科學很重要，因為它為今天提供了一個明確的警告，因為全球變暖正在加劇，同樣的海洋溫度模式正在發(fā)生。他們的研究成果發(fā)表在《科學進展》雜志上。

2013 was California's driest year on record, and it may foreshadow even drier decades to come. (Photo: Justin Sullivan/Getty Images)

And fewer storms means less rain in a region known to be dry and that gets roughly 70% of its rain during the late summer monsoon season.

而在一個干旱地區(qū)，風暴減少意味著降雨減少，而該地區(qū)約70%的降雨發(fā)生在夏末季風季節(jié)。

"For the southwestern U.S., I'm not optimistic about avoiding real megadroughts," says Ault, who worked on the study published in the Journal of Climate with researchers from the U.S. Geological Survey and the University of Arizona. "As we add greenhouse gases into the atmosphere — and we haven't put the brakes on stopping this — we are weighting the dice for megadrought."

“在美國西南部，我對避免真正的特大地震并不樂觀。”奧爾特說，他與美國地質(zhì)調(diào)查局和亞利桑那大學的研究人員共同參與了這項發(fā)表在《氣候雜志》上的研究。“隨著我們向大氣中添加溫室氣體——我們還沒有停止這一趨勢——我們正在為大規(guī)模排放做賭注。”

Low water marks on the dam at Elephant Butte, on the Rio Grande, near El Paso Texas. (Photo: Curt Teich & Co., Courtesy of Special Collections, University of Houston Libraries/Wikimedia Commons)

It's unclear how long current droughts across the Western U.S. will continue, Ault adds, but "with ongoing climate change, this is a glimpse of things to come. It's a preview of our future."

奧爾特補充說，目前還不清楚美國西部目前的干旱會持續(xù)多久，但“隨著氣候變化的持續(xù)，這只是未來的一個縮影。這是對我們未來的展望。”