​The reflectivity of snow and ice at the poles, known as the albedo effect, is one of Earth’s most important cooling mechanisms. But today, this reflectivity is being threatened by global warming, as the polar snow and ice melt, reducing the planet’s ability to reflect sunlight and setting off a dangerous warming loop: as more ice melts, the reflectivity decreases, the Arctic warms, and more ice melts. The volume of ice in the Arctic has shrunk 75% in the past 40 years, and scientists predict that summer ice there will disappear completely by the end of the century.

Climate Emergency: Feedback Loops