VOA科学技术2023--Sea Ice in Antarctica Falls to Record Lows

 

Sea Ice in Antarctica Falls to Record Lows

Sea ice in the Antarctic area fell to a record low this year. The drop is a result of rising temperatures worldwide. And there is no quick fix to make up for the damage, scientists said recently in a new study.

Antarctica's minimum summer ice cover, which last year dropped below 2 million square kilometers for the first time since satellite monitoring began in 1978, fell further to a new low in February.

The scientists' findings appeared in the publication Frontiers in Environmental Science.

Anna Hogg of the University of Leeds in Britain was one of the study's co-writers. When speaking about the melting icebergs¹ and shelves, she said "It's going to take decades if not centuries for these things to recover. There's no quick fix to replacing this ice."

She told a group of reporters, "It will certainly take a long time, even if it's possible."

This year's sea ice minimum is 20 percent lower than the average over the last 40 years. The sea ice loss represents an area nearly 10 times that of New Zealand, said Tim Naish of the Antarctic Research Center at New Zealand's Victoria University of Wellington. Naish was not part of the study.

Naish added that in some cases we are getting close to important large changes that could lead to serious consequences for future generations.

The warming of Earth's surface driven by the burning of fossil fuels has made Antarctica more likely to suffer from extreme events. And the effect is almost "certain" to get worse, the study said.

Climate change will "lead to increases in the size and frequency" of heatwaves, ice shelf collapses² and declines in sea ice, it said.

The study drew on recent evidence from scientific studies of the Antarctic Ocean, atmosphere, cryosphere and biosphere³.

The exact effects of climate change on Antarctica and the surrounding ocean have been uncertain. Scientists have had problems measuring how much the Earth's warming is affecting the thickness of Antarctic ice.

But from events such as the fast decline in sea ice, it is "scientifically reasonable" to assume that extreme events are going to become worse as temperatures rise worldwide, said Martin Siegert of the University of Exeter, another study co-writer.

Last year, an "atmospheric⁴ river" coming from Australia pushed heat and moisture into Antarctica. The result was temperatures up to 38.5 Celsius⁵ above normal, the largest variance⁶ from the norm the world has ever experienced.

Siegert described the temperature increase as "absolutely astonishing." Siegert added that if the event had happened during the Antarctic summer, instead of winter, it would have caused melting on the surface of the East Antarctic ice sheet, which has so far been saved from melting.

Siegert used the term fragile, meaning easily broken or damaged, to describe Antarctica.

"Antarctica is fragile as an environment, but extreme events test that fragility," he said. "What we're deeply concerned about is the increase in intensity⁷ and frequency of extreme events and the .... influences that they have in other areas."

Words in This Story

monitor -- v. to watch or observe for a special purpose over a period of time

shelf -- n. a flat area of rock, sand, etc., especially underwater

decade – n. a period of 10 years

consequence -- n. something that happens as a result of an action

fossil fuel -- n. a fuel (such as coal or oil) that is formed in the earth from dead plants or animals

certain – adj. used to say that something will definitely happen

frequency – n. the number of times that something happens during a particular period

variance – n. an amount of difference or change

astonishing – adj. causing a feeling of great surprise or wonder

1 icebergs   

n.冰山，流冰( iceberg的名词复数 )

参考例句：

• The drift of the icebergs in the sea endangers the ships. 海上冰山的漂流危及船只的安全。 来自《简明英汉词典》
• The icebergs towered above them. 冰山高耸于他们上方。 来自辞典例句

2 collapses   

折叠( collapse的第三人称单数 )； 倒塌； 崩溃； （尤指工作劳累后）坐下

参考例句：

• This bridge table collapses. 这张桥牌桌子能折叠。
• Once Russia collapses, the last chance to stop Hitler will be gone. 一旦俄国垮台，抑止希特勒的最后机会就没有了。

3 biosphere   

n.生命层，生物圈

参考例句：

• The entire biosphere was becoming more transparent.整个生物圈越来越透明。
• The impact of modern technology on the biosphere is evident worldwide.现代技术对生物圈的影响在全世界是明显的。

4 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

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 variance   

n.矛盾，不同

参考例句：

• The question of woman suffrage sets them at variance. 妇女参政的问题使他们发生争执。
• It is unnatural for brothers to be at variance. 兄弟之间不睦是不近人情的。

7 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。