Would the whole world end up underwater?
The polar ice caps look alike, but beneath the surface they are very different. Arctic ice floats on the Arctic Ocean, while the Antarctic sits on solid land. This might seem like a trivial difference, but it has a huge impact on what could happen if both were to suddenly melt. Polar ice caps melting into the sea is a bit like ice cubes melting into a drink. When you drop ice cubes into a glass, the water level rises immediately because of displacement. If those ice cubes melt, the water level doesn’t rise any further. This is the current situation in the Arctic.
But, if you keep dropping more ice into the glass, eventually it will overflow. This is where the Antarctic and Greenland come in. Together, they contain 75 percent of Earth’s fresh water, and unlike the Arctic ice, it is sitting on dry land. If it melts, or if chunks fall into the ocean, it’s going to cause major problems. According to NASA, if both of these ice sheets disappeared, the sea level would rise by 75 metres, plunging major coastal cities underwater, submerging entire islands, and causing many inland rivers and lakes to burst their banks.
But this is just the beginning. Although Arctic ice is already floating in the water, it still has the potential to contribute to rising sea levels. The bright crystals of ice and snow reflect 85 percent of the sunlight that hits them, while seawater absorbs about 90 per cent. If the Arctic disappeared to reveal the ocean beneath, the cooling effect would be removed and water temperatures would rise. In turn, this would cause more ice to melt, and less sunlight to be reflected – we would be caught in a dangerous warming cycle.
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