Kenya Using Lion Contraceptive to Protect Black Rhinos From Predatort
VOA News｜Science & Health
Ausust 07,2020 09:10 PM (source)
Canada's Last Intact Ice Shelf Collapses Due to Warming
August 07, 2020 09:10 PM
Much of Canada's remaining intact ice shelf has broken apart into hulking iceberg islands thanks to a hot summer and global warming, scientists said.
Canada's 4,000-year-old Milne Ice Shelf on the northwestern edge of Ellesmere Island had been the country's last intact ice shelf until the end of July when ice analyst Adrienne White of the Canadian Ice Service noticed that satellite photos showed that about 43% of it had broken off. She said it happened around July 30 or 31.
Two giant icebergs formed along with lots of smaller ones, and they have already started drifting away, White said. The biggest is nearly the size of Manhattan — 21 square miles (55 square kilometers) and 7 miles long (11.5 kilometers). They are 230 to 260 feet (70 to 80 meters) thick.
"This is a huge, huge block of ice," White said. "If one of these is moving toward an oil rig, there's nothing you can really do aside from move your oil rig."
The 72-square mile (187 square kilometer) undulating white ice shelf of ridges and troughs dotted with blue meltwater had been larger than the District of Columbia but now is down to 41 square miles (106 square kilometers).
Temperatures from May to early August in the region have been 9 degrees (5 degrees Celsius) warmer than the 1980 to 2010 average, University of Ottawa glaciology professor Luke Copland said. This is on top of an Arctic that already had been warming much faster than the rest of globe, with this region warming even faster.
"Without a doubt, it's climate change," Copland said, noting the ice shelf is melting from both hotter air above and warmer water below.
"The Milne was very special," he added. "It's an amazingly pretty location."
Ice shelves are hundreds to thousands of years old, thicker than long-term sea ice, but not as big and old as glaciers, Copland said.
Canada used to have a large continuous ice shelf across the northern coast of Ellesmere Island in the Canadian territory of Nunavut, but it has been breaking apart over the last decades because of man-made global warming, White said. By 2005 it was down to six remaining ice shelves but "the Milne was really the last complete ice shelf," she said.
"There aren't very many ice shelves around the Arctic anymore," Copland said. "It seems we've lost pretty much all of them from northern Greenland and the Russian Arctic. There may be a few in a few protected fjords."
科學家表示由於炎熱的夏天和全球暖化，加拿大（Canada）剩餘大部分完整的冰架(ice shelf)已經崩塌成了巨大而笨重的(hulking， 註 1)冰山島嶼。
直到 7 月底前，位於埃爾斯米爾島（Ellesmere Island）西北邊陲的米爾恩冰架（Milne Ice Shelf， 音釋）是加拿大最後一個完整的(intact， 註 2)冰架。加拿大極冰局（Canadian Ice Service）分析師阿德里安娜．懷特（Adrienne White，音釋）注意到衛星(satellite)照片有大約 43％ 的冰架坍塌，並表示該事件大約發生於 7 月 30 或 31 日左右。
懷特說，兩座巨大冰山和許許多多的小冰山成型，而且開始漂浮流動。最大的一塊幾乎與曼哈頓 （Manhattan）同樣大：面積 21 平方英里（55 平方公里），長度 7 英里（11.5公里），厚度 230 到 260 英尺（70 到 80 米）。懷特說：「這是一個巨大的冰塊，假設其中一座正朝向石油鑽井平台(oil rig)移動，除了把鑽油平台移走，我們別無選擇。」
山脊(ridges)和海槽(troughs)被藍色雪水所覆蓋，他們綿延起伏的(undulating， 註 3)白色冰架有 72 平方英里（187 平方公里）大，曾比哥倫比亞特區 （District of Columbia）還大，但現在已經下降到 41 平方英里（106 平方公里）。
該地區五月至八月初的溫度比 1980 年至 2010 年的平均氣溫高出 9 度（攝氏 5 度）， 渥太華大學（University of Ottawa）冰川學教授盧克．科普蘭（Luke Copland， 音釋）說：「過去以來，北極就比全球其他地區暖化更為快速，而現在速度又更快了。」
加拿大過去在努納武特地區（Nunavut）的埃爾斯米爾島北部海岸，有一個巨大連續的冰架，但由於人為造成的全球暖化，它在過去幾十年中一直在坍塌。懷特說，至 2005 年，只剩下六個冰架。科普蘭說道：「最後一個完整的冰架就只剩米爾恩。」
「北極（The Arctic）周圍已經沒有太多的冰架了」 科普蘭說：「我們似乎已經失去了從格陵蘭（Greenland）北部到俄羅斯北極圈（Russian Arctic）幾乎所有的冰架。在一些受保護的峽灣(fjords, ， 註 4)中可能還保存幾個。」
註 1：hulking 由名詞 "hulk" 「巨大笨重的船」與用於構成形容詞的 "-ing" 組成，意指「大而重的」
註 2：intact 於本文指「未受崩解」的冰架 ；本字也常指「完整無缺 ; 未經觸動的」; 注意重音在第 2 音節
註 3：undulating 於本文指「波狀起伏的，丘陵的」的冰架；本字也常指「 波動的」；注意重音在第 1 音節
註 4：fjords 也可拼為「fiords」；源自表示「入口, 河口」的古北歐語 fjörðr 和 「穿越之地」的北日耳曼語 ferthuz
BACK TO CONTENT
Check your comprehension!
Choose the BEST answer to each of the questions below. After you finish, highlight the parentheses to reveal the hidden answers.
1. ( C ) According to the article, what is FALSE about the Milne ice shelf?
(A) It is 4000 years old.
(B) It is no longer unbroken.
(C) It is 182 square kilometers.
(D) It broke around July 31.
2. ( A ) What does the article say about the effects of global warming in the Arctic?
(A) It has caused the Arctic to warm faster than other areas in the world.
(B) It has been contributing to other ice shelves and glaciers to melt quickly.
(C) It has changed the way people view the beauty of ice shelves in the Arctic.
(D) It has broken many oil rigs due to ice chunks breaking off ice shelves.
3. ( B ) Where does Copland say ice shelves may still be located?
(B) Protected fjords
(C) Ellesmere Island