进入查看： 2022-2023年英语周报七年级第30期答案汇总

 

A tiny clue found in ancient deposits(地质沉积物) has unlocked big secrets

about Greenland's past and future climate. Just beyond the northwest edge of the vast Greenland Ice Sheet, researchers have discovered lake mud that have survived

the last ice age. The mud and remains of common flies in it record two inter glacial

periods (间冰期) in northwest Greenland.

Although researchers have long known these two periods 一 the early Holocene and Last Inter glacial 一 experienced warming in the Arctic, the mix of fly species shows that Greenland was even warmer than previously thought. "As far as we know, it has never been found in Greenland. We think this is the first time anyone has reported it in ancient deposits or modern lakes there," Axford said."We were really surprised to see how far north it migrated (迁徙)."

This new information could help researchers better measure Greenland's sensitivity to warming, by testing and improving models of climate and ice sheet behaviour.Those models could then improve predictions of how Greenland's ice sheet might respond to man- made global warming. After all, Greenland covers 80per cent of the Arctic country and holds enough ice to equal 20 feet of global sea level."Northwest Greenland might feel really remote, but what happens to that ice sheet is going to matter to everyone in every coastal city around the world,”said Yarrow Axford, an associate professor in the team."One of the big uncertainties in climate science is how fast the Earth changes when it gets warmer. Geology gives us an opportunity to see what happened when the Earth was warmer than today." said Axford.