国家地理:不再冻人的五大湖(2)

But what Leavitt was doing the February day was a rare occurrence last winter across the Great Lakes. The long-term average for ice coverage on all five Great Lakes -- Superior, Michigan, Erie, Huron, and Ontario -- is 54 percent. Last winter, ice covered only 19.5% of the lake's surface is a near record low.

但这个二月天拉维特所做的事，在去年冬天的五大湖一带却不常见。长期以来，苏必利尔湖、密歇根湖、伊利湖、休伦湖、安大略湖这五大湖的平均覆冰量是54%。去年冬天却仅有19.5%的湖面有冰覆盖，几乎是创纪录地低。

Some lakes in the region didn't freeze at all. Others saw only faint traces of ice around their edges, or froze briefly. The weekend before Leavitt's outing, temperatures in the region shot up to 40 degrees Fahrenheit, and ice anglers slogged through slush in T-shirts.

这一带有些湖泊根本没有结冻。另一些则只在湖岸边有些微的冰，或只是暂时结冰。拉维特去冰钓前的那个周末，该地区的气温冲上了40华氏度，冰钓客是穿着T恤在雪泥中行走的。

One overly warm season isn't necessarily a harbinger of inevitable. But increasingly, scientists can pick out patterns in the scattershot records of change from across the Great Lakes, and those patterns are pointing toward a sobering conclusion: The 2019/2020 winter, with its faint traces of ice, is likely just a taste of the future.

一次温暖过头的冬季，不见得就预示了未来必定是如此。但是科学家也越来越能从五大湖各地散乱的变化纪录中看出模式，而这些模式全都指向一个令人警醒的结论：只有少许湖冰的2019至2020年冬季，可能只是让人提早体验未来。