国家地理:不再冻人的五大湖(3)

The Great Lakes account for about 20 percent of the freshwater on Earth's surface. The lakes' geographical¹ footprint is also hard to fathom². Their combined surfaces span more than 94,000 square miles, about the size of the United Kingdom. The combined measurement of the coasts of the five lakes is thousands of miles longer than either the Pacific or Atlantic coastline of the contiguous U.S.

五大湖约占地球淡水资源的20%。湖泊的地理分布也很难彻底理清。它们的流域总面积超过94000平方英里，大约相当于英国的面积。而这五个湖泊的海岸线的测量长度，要比美国的太平洋或大西洋海岸线长数千英里。

The presence of all that water was shaped by natural changes in Earth's climate through time. But the lakes now face unprecedented³ change—and this time, humans are behind it.

所有这些水资源的存在，都是由于地球气候随时间的自然变化而形成的。但是现在五大湖面临着前所未有的变化，而这一次，人类是幕后黑手。

The planet has warmed by an average of nearly two degrees Fahrenheit⁴ (one degree Celsius) since the 1880s. The Great Lakes region is on a par⁵ with this global trend: Within the basin, air temperatures have risen by an average of 1.6 degrees Fahrenheit compared with the first 60 years of the 1900s. And much of that warming has been concentrated in the winter months, nudging the ice ever closer to its tipping point.

从19世纪80年代开始到今天，地球平均变暖了近2华氏度（1摄氏度）。五大湖地区与全球趋势相当：盆地内的空气温度与20世纪前60年相比平均上升了1.6华氏度。而这种变暖主要集中在冬天的几个月里，冰层越来越接近它的临界点。

"Lake ice is an amazing indicator⁶ of climate," says Sapna Sharma, a lake ecologist at York University in Toronto. "It's a clear indication of climate change, and people have recorded it, in some cases, for centuries."

多伦多约克大学的湖泊生态学家萨佩纳·沙玛表示：“湖冰是一个关于气候的神奇的指标。这是气候变化的一个明显迹象，人们在某些情况下已经记录了几个世纪。”

1 geographical   

adj.地理的；地区(性)的

参考例句：

• The current survey will have a wider geographical spread.当前的调查将在更广泛的地域范围內进行。
• These birds have a wide geographical distribution.这些鸟的地理分布很广。

2 fathom   

v.领悟，彻底了解

参考例句：

• I really couldn't fathom what he was talking about.我真搞不懂他在说些什么。
• What these people hoped to achieve is hard to fathom.这些人希望实现些什么目标难以揣测。

3 unprecedented   

adj.无前例的，新奇的

参考例句：

• The air crash caused an unprecedented number of deaths.这次空难的死亡人数是空前的。
• A flood of this sort is really unprecedented.这样大的洪水真是十年九不遇。

4 Fahrenheit   

n./adj.华氏温度；华氏温度计(的)

参考例句：

• He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
• The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。

5 par   

n.标准，票面价值，平均数量；adj.票面的，平常的，标准的

参考例句：

• Sales of nylon have been below par in recent years.近年来尼龙织品的销售额一直不及以往。
• I don't think his ability is on a par with yours.我认为他的能力不能与你的能力相媲美。

6 indicator   

n.指标；指示物，指示者；指示器

参考例句：

• Gold prices are often seen as an indicator of inflation.黃金价格常常被看作是通货膨胀的指标。
• His left-hand indicator is flashing.他左手边的转向灯正在闪亮。