In 2011, annual snow cover extent over Northern Hemisphere continents (including the Greenland ice sheet) averaged 24.7 million square kilometers, which is 0.3 million square kilometers less than the long-term average.

Kristin Laidre, a marine mammal biologist, has taken more than thirty trips to the Arctic, many of them to study the mysterious narwhal. Although the narwhal has appeared in stories throughout history, scientists are just beginning to understand this quirky creature with a fierce survival instinct. But in recent years, a series of unusual events led Laidre to wonder if narwhals are being caught off guard by changes in their unforgiving environment…

Climate scientist Anthony Janetos makes it clear that climate change isn't some future abstraction: real and substantial impacts on people's lives, the economy, the environment, and our valuable natural resources are already happening here in the United States.

 

This year’s Arctic Report Card emphasizes that climate change is more prominent in the Arctic than at lower latitudes.

Jackie Richter-Menge describes the "Arctic amplification" phenomenon: how the loss of Arctic sea ice leads to further warming.

In the 2011 Arctic Report Card, scientists report that the bright white surface of the Greenland Ice Sheet has grown less reflective. The darker surface absorbs more sunlight, accelerating melting.

Phytoplankton productivity has increased 20 percent over the past decade as sea ice extent declines and more open water habitat is available.

Satellite observations show that as the Arctic tundra has grown warmer in the past three decades, it has also grown “greener.”

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