VOA标准英语2012--Study: Warm Ocean Speeds Antarctic Melting

Study: Warm Ocean Speeds Antarctic Melting

The study's lead author, Hamish Pritchard, is a glaciologist with the British Antarctic Survey. In 1993, and again in 2003, he observed the collapse¹ of two ice shelves on the Antarctic Peninsula. He says the glaciers³ they had been holding back picked up speed and flowed six times faster than normal into the Southern Ocean.

When Pritchard’s team deployed⁴ satellite laser instruments to measure changes in the Antarctic ice shelves between 2003 and 2008 they saw a distinct pattern.

“Some of the ice shelves were lowering quite strongly," he says, "and in particular those were the ice shelves in west Antarctica.”

Previous studies looking for the causes of the shrinking ice shelves had ruled out decreased snowfall or any slow-down in the movement of glaciers toward the sea.

Pritchard says the new data points to a process they call “basal melt:” warmer ocean water heating the ice shelf from below. 

“We looked at 54 ice shelves around Antarctica and of those, 20 were thinning by this process. Going beyond that we found in every case where we saw this ice shelf thinning by basal melt, we also saw thinning by acceleration⁵ of the glaciers that drained from the ice sheet.”

Pritchard says stronger westerly winds in the Southern Ocean are driving warmer ocean currents closer inland to ice shelves on the Antarctic coast. “It tells us that the ice shelves can be very sensitive to quite subtle changes in the climate, such as the wind patterns, that we hadn’t really appreciated before.”

Jan Gunnar Winther, director of the Norwegian Polar Institute, is not affiliated⁶ with the study. He says the research provides important new insight into how climate change-induced melting of the Earth’s polar ice sheets is affecting global sea levels. 

“In very many places around the world, most places where you have glaciers, and in Greenland, in parts of Antarctica, not in all of Antarctica, they add to the global sea level and they may already be, from what we know, the most important explanation of why we have an increased sea level." 

Winther says emissions⁷ from fossil-fuel combustion⁸ in our power plants, cars and buildings continue to pump global warming gases into the atmosphere. As Prichard and colleagues note in their Nature study, these warming trends are driving wind and ocean current changes that are speeding up the melting and thinning of Antarctic ice.

That dynamic appears to be self-sustaining, the researchers warn, concluding that it “may have already triggered a period of unstable⁹ glacier² retreat” across the western Antarctic ice sheet.

1 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

2 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。

3 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）

4 deployed   

（尤指军事行动）使展开( deploy的过去式和过去分词 )； 施展； 部署； 有效地利用

参考例句：

• Tanks have been deployed all along the front line. 沿整个前线已部署了坦克。
• The artillery was deployed to bear on the fort. 火炮是对着那个碉堡部署的。

5 acceleration   

n.加速，加速度

参考例句：

• All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
• He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。

6 affiliated   

adj. 附属的, 有关连的

参考例句：

• The hospital is affiliated with the local university. 这家医院附属于当地大学。
• All affiliated members can vote. 所有隶属成员都有投票权。

7 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

8 combustion   

n.燃烧；氧化；骚动

参考例句：

• We might be tempted to think of combustion.我们也许会联想到氧化。
• The smoke formed by their combustion is negligible.由它燃烧所生成的烟是可忽略的。

9 unstable   

adj.不稳定的，易变的

参考例句：

• This bookcase is too unstable to hold so many books.这书橱很不结实，装不了这么多书。
• The patient's condition was unstable.那患者的病情不稳定。