At present, it becomes a research hotspot in the world to study the changes of elevation and mass balance of polar ice sheets by satellite altimetry.
提要采用卫星测高技术研究两极冰面高程变化和物质平衡状态是目前国际研究的一个热点。
The last expansion of the polar ice sheets took place about 18,000 years ago.
最后一次扩大发生在一万八千年前。
Glaciers and polar ice sheets will melt as temperatures increase, with some scientists predicting that sea levels could rise by four feet (1.4m) by 2100.
因为气温升高,冰川和极地冰盖将融化。一些科学家预言,到2100年,海平面可能上升4英尺1.4米。
The melting of glaciers, ice caps and polar ice sheets on land, however, has the potential to account for much more.
然而,陆地上的冰川、冰盖和极地冰盾的融化有更大的潜在力量。