VOA慢速英语2020--加拿大最后一个完整北极冰架坍塌

The last fully¹ complete ice shelf in the Canadian Arctic² has collapsed³.

The Milne Ice Shelf is at the edge of Ellesmere Island, in the far northern Canadian territory of Nunavut. The ice shelf, researchers say, lost more than more than 40 percent of its area in just two days at the end of July.

"Above normal air temperatures, offshore⁴ winds and open water in front of the ice shelf are all part of the recipe for ice shelf break up," the Canadian Ice Service said on Twitter when it announced the loss earlier this month.

Luke Copland is a glaciologist at the University of Ottawa and was part of the research team studying the Milne Ice Shelf. "...Cities are that size," he said. "These are big pieces of ice."

The shelf's area shrank by about 80 square kilometers. By comparison, the island of Manhattan in New York covers about 60 square kilometers.

The Arctic has been warming at two times the worldwide rate for the last 30 years. This year, temperatures in the polar area have been especially intense. The polar sea ice hit its lowest total amount for July in 40 years. Record heat and wildfires have burned Siberian Russia.

Summer in the Canadian Arctic this year has been 5 degrees Celsius⁵ above the 30-year average, Copland said. That has threatened smaller ice caps, which can melt quickly because they do not have the weight that larger glaciers⁷ have to stay cold. As a glacier⁶ disappears, more bedrock is left uncovered. This then speeds up the melting process.

A research camp, including instruments for measuring water flow through the ice shelf, was lost when the shelf at Ellesmere Island collapsed. "It is lucky we were not on the ice shelf when this happened," researcher Derek Mueller of Carleton University in Ottawa wrote in a recent online article.

Ellesmere also lost its two St. Patrick Bay ice caps this summer.

"It was only a matter of time," said Mark Serreze, director of the National Snow and Ice Data Center (NSIDC) in Boulder⁸, Colorado.

Serreze and other scientists at the center had published a 2017 study predicting the ice caps were likely to disappear within five years. Scientists believe the ice caps formed several centuries ago.

Their disappearance⁹, Serreze said, was confirmed last month, when NASA satellite images of the area showed a complete lack of snow and ice.

Serreze studied the ice caps as a student on his first trip to the Arctic many years ago. At the time, he said, the caps had seemed like immovable parts of the surrounding area.

"When I was there in the 1980s I knew every square inch of those ice caps," Serreze said. "You have the memories. It's like your first girlfriend."

Another two ice caps on Ellesmere - called Murray and Simmons - are also shrinking and are likely to disappear within 10 years, Serreze said.

I'm Ashley Thompson.

Words in This Story

ice shelf - n. a floating sheet of ice attached to a landmass.

offshore - n. moving away from the shore toward the water

recipe - n. a way of doing something that will produce a particular result

glacier - n. a very large area of ice that moves slowly down a slope or valley or over a wide area of land

glaciologist - n. a person who studies glaciers

ice cap - n. a covering of ice over a large area, especially on the polar area of a planet.

bedrock - n. the solid rock that lies under the surface of the ground

1 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

2 Arctic   

adj.北极的；n.北极

参考例句：

• They flew over the unlimited reaches of the Arctic.他们飞过了茫茫无边的北极上空。
• The sort of animal lived in the Arctic Circle.这种动物生活在北极圈里。

3 collapsed   

adj.倒塌的

参考例句：

• Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
• The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。

4 offshore   

adj.海面的，吹向海面的；adv.向海面

参考例句：

• A big program of oil exploration has begun offshore.一个大规模的石油勘探计划正在近海展开。
• A gentle current carried them slowly offshore.和缓的潮流慢慢地把他们带离了海岸。

5 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

6 glacier   

n.冰川，冰河

参考例句：

• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。
• The upper surface of glacier is riven by crevasses.冰川的上表面已裂成冰隙。

7 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

8 boulder   

n.巨砾；卵石，圆石

参考例句：

• We all heaved together and removed the boulder.大家一齐用劲，把大石头搬开了。
• He stepped clear of the boulder.他从大石头后面走了出来。

9 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。