美国西南部可能会在本世纪迎来“超级飓风”

美国西南部可能会在本世纪迎来“超级飓风”

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.

美国西南部对干旱并不陌生，但它可能很快就会比几千年来干旱得更多。据一项研究显示，由于人为造成的气候变化，该地区10年干旱的可能性现在至少为50%，而其“大干旱”(可能持续30多年)的可能性在下个世纪从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.

最近的一项研究也得出了同样的结论，但试图回答更大的问题:是什么导致了特大光以及什么因素控制了它们的出现时间?研究报告的主要作者内森·斯泰格尔和哥伦比亚大学地球研究所的同事们研究了气候模型，以找出为什么9世纪至16世纪经历了这样的干旱，但从那以后就没有了。他们发现，太平洋海洋表面温度的下降、大西洋表面温度的上升和“辐射强迫”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.

科学很重要，因为它为今天提供了一个明确的警告，因为全球变暖正在加剧，同样的海洋温度模式正在发生。他们的研究成果发表在《科学进展》杂志上。

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.

而在一个干旱地区，风暴减少意味着降雨减少，而该地区约70%的降雨发生在夏末季风季节。

"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."

“在美国西南部，我对避免真正的特大地震并不乐观。”奥尔特说，他与美国地质调查局和亚利桑那大学的研究人员共同参与了这项发表在《气候杂志》上的研究。“随着我们向大气中添加温室气体——我们还没有停止这一趋势——我们正在为大规模排放做赌注。”

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."

奥尔特补充说，目前还不清楚美国西部目前的干旱会持续多久，但“随着气候变化的持续，这只是未来的一个缩影。这是对我们未来的展望。”