美國(guó)西南部可能會(huì)在本世紀(jì)迎來“超級(jí)颶風(fēng)”

美國(guó)西南部可能會(huì)在本世紀(jì)迎來“超級(jí)颶風(fēng)”

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(guó)西南部對(duì)干旱并不陌生，但它可能很快就會(huì)比幾千年來干旱得更多。據(jù)一項(xiàng)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(gè)世紀(jì)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(xiàng)研究也得出了同樣的結(jié)論，但試圖回答更大的問題:是什么導(dǎo)致了特大光以及什么因素控制了它們的出現(xiàn)時(shí)間?研究報(bào)告的主要作者內(nèi)森·斯泰格爾和哥倫比亞大學(xué)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(jì)至16世紀(jì)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(qiáng)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(xué)很重要，因?yàn)樗鼮榻裉焯峁┝艘粋€(gè)明確的警告，因?yàn)槿蜃兣诩觿?，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(xué)進(jìn)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(gè)干旱地區(qū)，風(fēng)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(fēng)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(guó)西南部，我對(duì)避免真正的特大地震并不樂觀。”奧爾特說，他與美國(guó)地質(zhì)調(diào)查局和亞利桑那大學(xué)的研究人員共同參與了這項(xiàng)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(shì)——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(bǔ)充說，目前還不清楚美國(guó)西部目前的干旱會(huì)持續(xù)多久，但“隨著氣候變化的持續(xù)，這只是未來的一個(gè)縮影。這是對(duì)我們未來的展望。”