As the air space around them is lessened by compaction and melting, the grains become denser.
由于它们周围的空气被压缩、融化而逐渐减少，颗粒变得更加密集了。
2
Increases in global average air and sea temperature, ice melting and rising global sea levels all help us understand and prepare for the coming challenges.
全球空气和海洋平均温度上升、冰在融化、全球海平面上升，这一切使我们了解和准备应对即将到来的挑战。
3
The warmer ocean would heat the air above it, which would slow the refreezing of ice in winter, which would in turn become even more susceptible to melting in summer.