This animation, based on simulations produced by the Community Climate System Model, shows the year-to-year variability of Arctic sea ice. For much of the 20th century, the model accurately captures the expansion and contraction of the area covered by sea ice from one late summer to the next, based on natural climate cycles. By the end of the 20th century, however, the ice began to retreat significantly because of global warming.

Within a few decades or sooner, the model simulations show that the ice is likely to shrink abruptly, losing about two-thirds of its area over the course of about a decade. By about 2040, the Arctic may be nearly devoid of sea ice during the late summer unless greenhouse gas emissions are significantly curtailed. (©UCAR, animation.) News media terms of use*

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