Climate feedbacks: Ice and snow

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The amount of sunlight reflected by a surface is known as its albedo. Ice and snow are bright surfaces with high albedo, reflecting about 60–80% of the sunlight falling on them. So ice on water or snow on land keeps the Earth cooler than it would otherwise be. An initial change such as a rise in temperature can trigger a feedback – melting some snow and ice leads to the exposure of low-albedo land or water surfaces, which increases the amount of sunlight absorbed by the Earth’s surface, leading to a further rise in temperature as a result. This is known as the ice-albedo feedback.