Across the icy dome that crowns the Earth, rising temperatures are turning the tundra greener and more lush. Beavers are expanding their range. Garbage from passing ships is fouling the shores. Wildfires are scorching the once permanently frozen lands of Siberia.

Such is the picture that scientists painted in their latest assessment of the Arctic, which is heating up more than twice as quickly as the rest of the globe. This warming has propelled a variety of disruptions that make the polar region a potential harbinger for what people at lower latitudes might someday experience as a result of human-induced climate change.

"The vulnerabilities in the Arctic are more noticeable,” said Matthew Druckenmiller of the University of Colorado Boulder’s National Snow and Ice Data Center, who was an editor of the new assessment. "But these are similar vulnerabilities that we’re going to see unfold for our entire planet in the decades to come.”