The ice sheet was assumed to have been stable.

冰盖被默认为是稳定的。

Now, new evidence reveals that all or most of the Antarctic ice sheet collapsed at least once during the past 1.3 million years.

现在，新的证据显示，在过去130万年中，全部的南极冰盖或其中大部分至少都崩塌过一次。

Unlike floating ice shelves which have little impact on sea level when they break up, the ice sheet is anchored to bedrock will blow the sea surface.

当浮动冰架破裂时，对海平面的影响很小；而与之不同的是，固定在基岩上的冰盖将会使海面炸毁。

As Herman Engleheart, a co-author from the California Institute of Technology says, "the West Antarctic ice sheet disappear once and can disappear again."

正如加州理工学院的赫尔曼·恩格尔哈特所说，“南极西部冰盖消失过一次，也可能再次消失。”

Scientists agree that the key player in this scenario is the West Antarctic ice sheet, a Brazil-size mass of frozen water that is as much as 7000 feet thick.

科学家们一致认为，这一情境中的关键推手是南极西部的冰层，这是一块跟巴西（面积）差不多大小的冰原，厚达7000英尺。

It would take the melting of an ice sheet to do that.

但是，一个大冰原的融化就不同了。

This gives us an idea of how fast a large ice sheet can melt.

这告诉了我们冰原会以多快的速度融化。

But the Greenland ice sheet is not one solid, smooth mass of ice.

但是，格陵兰冰盖不是一个牢固光滑的冰体。

The satellite USES radar to measure its altitude above the ice sheet.

卫星用雷达测定卫星从冰层顶部算起的高度。

Greenland's massive ice sheet holds about 20 percent of the world's ice.

格陵兰巨大冰盖的冰量大约占世界的20%。

The Antarctic Ice Sheet waxed and waned, and global sea level rose and fell.

随着南极冰盖冰冻和消融，全球海平面也在降低和升高。

Greenland's ice sheet could break up if the temperature rises by as little as 2c.

如果气温上升仅仅2c，格陵兰冰盖就可能毁掉。

The blue diamond is one vivid pointer to the antiquity of the Greenland ice sheet.

蓝钻石是显示格陵兰冰盖有多古老的生动指针。

It is not simply that the ice sheet is melting steadily as global temperatures rise.

这并不仅仅是说随着全球气温升高，冰盖在稳步融化。

The only uncertainty is the time it would take for complete ice sheet disintegration.

唯一不确定的是要多久完整的冰层才会分崩离析。

A fresh coat of summer snow would have protected the ice sheet, but little snow fell.

一层新的夏季雪本可以保护冰原，但几乎没怎么下雪。

Several metres of sea level rise is now inevitable as the Greenland ice sheet disappears.

现在，随着格陵兰冰原的消失，海平面上升几米已是不可避免。

The ice sheet margin appears to be grey, which may be a sign it is saturated with water...

冰盖边缘是灰色的，这可能是冰川融化的一个信号......

According to Straneo, the rapid changes to the ice sheet have taken glaciologists by surprise.

据斯特拉内奥说，冰盖的迅速变化令冰川学家措手不及。

The giant Greenland ice sheet may be more resistant to temperature rise than experts realised.

也许广袤的格林兰冰原对温度升高的抵御能力比专家们估计的要强得多。

But it did not destabilise the ice sheet or provide a new reason to worry about rising sea levels.

但这并没有导致大冰盖发生不稳定现象，也无法为海平面上升的担忧提供新的依据。

There is 10 feet of sea level rise stored up in the unstable part of the West Antarctic ice sheet.

西南极冰架的不稳定部分一旦融化，会让海平面上升10英尺。

Konrad Steffen of the University of Colorado, Boulder, leads one study of the Greenland ice sheet.

位于博尔德的科罗拉多州大学的Konrad Steffen先生负责一项格陵兰冰原项目研究。

Our theory links an external climate-driven process, the melting of the ice sheet, and earthquakes.

我们的理论将外部气候驱动过程，冰盖融化与地震联系起来。

The melting of Greenland's ice sheet is accelerating, threatening an increasing rise in sea levels.

格陵兰岛冰层的融化速度正在加快，可能导致海平面加速上升。

By 2100 they may surge by five times that, or even more if Greenland's ice sheet starts to collapse.

到2100年，如果格陵兰冰原开始融化，海平面会急剧上升，达到上世纪上升幅度的五倍甚至更多。

Melt along the southern edge of Greenland's ice sheet is now moving up its northwest coast, a new study shows.

一项新的研究表明，格陵兰冰盖南部沿线的冰融如今正蔓延到它的西北海岸线。

Whether acceleration of melting from the Greenland Ice Sheet will continue, he added, is a big question mark.

他补充道，格林兰冰盖是否会继续加速融化还是一个大问号。

A 2009 study found that the Greenland ice sheet shed roughly 385 cubic miles of ice over the previous seven years.

2009年的一项研究发现，此前七年间格陵兰冰盖差不多融掉了385立方英里。