WHY ARE THEY IMPORTANT AND WHAT’S HAPPENING TO THEM?
Greenland (near the North Pole) and Antarctica (South Pole) are home to most of the world’s glacial ice, including its only two ice sheets. Glaciers and ice sheets have been appearing in the news quite frequently in the past few years as they are increasingly unstable due to global warming. Just before Christmas it was reported that the Thwaites Glacier in the Antarctic, which is the widest glacier in the world and is sometimes referred to as the ‘Doomsday Glacier’, could collapse in as little as five years. Candice Moen has a closer look at our earth’s ice.
THE HISTORY OF ICE ON EARTH
There have been many ice ages on earth, most of them long before humans made their first appearance. These ice ages would have ranged from “comparatively mild” to “so severe that the entire Earth froze over for tens or even hundreds of millions of years”. Looking back over the history of these ice ages, the planet seems to have three main settings: ‘greenhouse’, when tropical temperatures extend to the poles and there are no ice sheets at all; ‘icehouse’, when there is some permanent ice, although its extent varies greatly; and ‘snowball’, in which the planet’s entire surface is frozen over. During the different greenhouse, icehouse and snowball there was ice present in various different locations across the earth’s surface.