美国国家公共电台 NPR The Sea Level Threat To Cities Depends On Where The Ice Melts — Not Just How Fast

 

ELISE HU, HOST:

The world's oceans are rising up about eight inches on average over the past century. The seas are rising more in some places than others. As NPR's Christopher Joyce reports, scientists are beginning to predict where the rise will be most severe.

CHRISTOPHER JOYCE, BYLINE¹: A warming climate is melting a lot of glaciers² and ice sheets on land. That's more water rolling down into the oceans. But the oceans are not like a bathtub. The water doesn't rise uniformly. To understand why, think of the Earth as a spinning top with a bit of a wobble. Eric Larour, who studies the planet's frozen regions, says that when huge ice sheets - some 2 miles thick - start to melt, it affects the Earth's rotation³.

ERIC LAROUR: What happens when you change the mass of the ice, the modification⁴ itself makes the wobble change. And this in turn changes the shape of the ocean on the Earth.

JOYCE: When the wobble shifts, the oceans shift as if you were shaking a mound⁵ of grandma's Jell-O dessert on the Thanksgiving table. That's part of the story, but something else happens, too. Many ice sheets and glaciers are so massive they exert a significant gravitational field, almost as if they were small versions of the moon. The force is tiny, but it does attract nearby ocean water.

LAROUR: So what happens when the ice melts is that there is less of it. And so the ocean recedes⁶ away from the mass of ice.

JOYCE: Larour's team at NASA's Jet Propulsion Lab has mapped how changes in these giant ice fields influence sea levels both nearby and thousands of miles away. They published their results in the journal Science Advances.

For example, the ocean along Norway's coast could actually drop a tiny bit if nearby ice sheets in eastern Greenland melt. Meanwhile, those Greenland ice sheets could raise sea levels by inches on the other side of the planet in places like Tokyo. Larour says this is useful information.

LAROUR: Out of all the masses of ice around the Earth - Alaska glaciers, Greenland, Antarctica, Patagonia, Himalaya - which ones are going to be contributing to sea level in New York?

JOYCE: It turns out that in New York City, the sea level would be affected⁷ more by melting ice on the northern end of Greenland than from ice in Canada. Scientists are now using this information to predict the future for American cities. But they're also building in a lot of local geographical⁸ information. Oceanographer William Sweet is one of them. He has a personal interest. He lives along the Chesapeake Bay.

WILLIAM SWEET: Right here on the Severn River we are somewhere very likely to experience 25 to 50 percent more than the global average.

JOYCE: Sweet's at the National Oceanic and Atmospheric⁹ Administration. He says NOAA is putting together a sea level rise grid¹⁰ for the country.

SWEET: So it really matters when you go to start planning on, I'm going to be prepared for 1 meter of sea level rise. Well, you might really want to be prepared for 4 to 5 feet. One thing's for certain. Once you wait until you realize you have a problem, it's going to be chronic¹¹ rather quickly.

JOYCE: Already, scores of coastal¹² cities are flooding much more often than they used to. As the climate warms, that kind of flooding could become the norm. Christopher Joyce, NPR News.

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1 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

2 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）

3 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。

4 modification   

n.修改，改进，缓和，减轻

参考例句：

• The law,in its present form,is unjust;it needs modification.现行的法律是不公正的，它需要修改。
• The design requires considerable modification.这个设计需要作大的修改。

5 mound   

n.土墩，堤，小山；v.筑堤，用土堆防卫

参考例句：

• The explorers climbed a mound to survey the land around them.勘探者爬上土丘去勘测周围的土地。
• The mound can be used as our screen.这个土丘可做我们的掩蔽物。

6 recedes   

v.逐渐远离( recede的第三人称单数 )；向后倾斜；自原处后退或避开别人的注视；尤指问题

参考例句：

• For this reason the near point gradually recedes as one grows older. 由于这个原因，随着人渐渐变老，近点便逐渐后退。 来自辞典例句
• Silent, mournful, abandoned, broken, Czechoslovakia recedes into the darkness. 缄默的、悲哀的、被抛弃的、支离破碎的捷克斯洛伐克，已在黑暗之中。 来自辞典例句

7 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

8 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。

9 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。

10 grid   

n.高压输电线路网；地图坐标方格；格栅

参考例句：

• In this application,the carrier is used to encapsulate the grid.在这种情况下，要用载体把格栅密封起来。
• Modern gauges consist of metal foil in the form of a grid.现代应变仪则由网格形式的金属片组成。

11 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

12 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。