國(guó)家地理:不再凍人的五大湖(6)

Leavitt isn't alone. Ice provides crucial things to everyone who goes out on it. Respite for some, dearly held recreation for others, food, and much more. Snow and ice also are critical components of local U.S. economies across the region: Winter skiing and snowmobiling account for some $3.5 billion, a recent estimate said. A single ice fishing tournament can inject hundreds of thousands of dollars into communities.

拉維特并不是唯一一個(gè)這樣的人。冰面為每一個(gè)出來(lái)站在上面的人都提供了至關(guān)重要的東西。對(duì)一些人來(lái)說(shuō)是一個(gè)喘息的機(jī)會(huì)，對(duì)另一些人來(lái)說(shuō)，這是一個(gè)非常重要的娛樂(lè)活動(dòng)、食物，還有更多。與冰雪有關(guān)的活動(dòng)也是整個(gè)地區(qū)當(dāng)?shù)亟?jīng)濟(jì)的重要組成部分：最近的一項(xiàng)評(píng)估顯示，冬季滑雪和雪地摩托大約貢獻(xiàn)了35億美元。而一場(chǎng)冰上釣魚(yú)錦標(biāo)賽可以為社區(qū)帶來(lái)數(shù)十萬(wàn)美元的收入。

But in parts of Lake Superior, the ice season has been shrinking by an average of almost a day each year for the past few decades. That means the year Leavitt was born, a winter on Superior would have included more than a month more ice cover than it does today. Superior also is warming faster than every other large lake on Earth, except Lake Fracksjon in Sweden.

但是在蘇必利爾湖的部分地區(qū)，在過(guò)去的幾十年里，冰期平均每年要減少近一天。這意味著拉維特出生的那一年，蘇必利爾的一個(gè)冬天，要比現(xiàn)在長(zhǎng)一個(gè)多月左右。蘇必利爾湖的變暖速度也比地球上其他任何一個(gè)大湖都要快，除了瑞典的Fracksjon湖。

The other Great Lakes' ice seasons are shrinking as well, by an average of about half a day per year. That may sound small and benign, but it masks much more critical change in a place where the line between ice and no ice, snow and rain, can be razor thin.

其他五大湖的冰期也在減少，平均每年減少約半天。這數(shù)字聽(tīng)起來(lái)可能不大，比較微妙，但它掩蓋了這個(gè)地區(qū)一個(gè)更為關(guān)鍵的變化，那就是有冰還是無(wú)冰，下雪還是下雨的界線變得很難區(qū)分。

It's difficult to see the change clearly, in some cases, says Jia Wang, a climatologist at NOAA who focuses on ice cover in the Great Lakes region. Though they're hundreds of miles from the oceans, the lakes feel weather influences from both the Pacific and the Atlantic, and incorporate those weather patterns into their own.

關(guān)注五大湖區(qū)域的冰層覆蓋情況的美國(guó)國(guó)家海洋和大氣管理局氣候?qū)W家王佳表示，在某些情況下，很難清楚地看到這種變化。盡管距離海洋有數(shù)百英里的距離，但這些湖泊還是受到了來(lái)自太平洋和大西洋的氣候影響，并將這些氣候模式融入到自己的模式中。