That warmth supports more tree and shrub growth, creating a positive feedback cycle to the warming, Beck said.
The findings match forecasts for Arctic greening predicted by various other methods, and they foreshadow effects that will strike closer to home later, Forbes said.
"What's happening now in the Arctic is a faster version of what will be happening at lower latitudes," Forbes told LiveScience.
That could worsen extreme weather events like Hurricane Sandy in the future.
"The snowstorms in Washington, D.C., and New York, and the flooding and the freezing on the River Thames - the extreme weather will continue to be extreme but it won't be so uncommon," Forbes said.
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The Reality of Climate Change: 10 Myths Busted Image Gallery: One-of-a-Kind Places on Earth 10 Things You Need to Know about Arctic Sea Ice This article originally appeared on LiveScience. Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.