The surface melt season on Greenland lasted up to 30 days longer than average in 2011, and it affected 31 percent of the ice sheet surface. Ice mass loss from Greenland in 2011 was about 430 gigatons—enough ice to raise global sea level by just over 1 millimeter.

Continuing a decade-long phenomenon, above-average warmth in the Arctic this year was two or more times greater than warming observed at lower latitudes.

This animation of photo-like satellite images documens the extreme variability of surface melt on part of the Greenland Ice Sheet in the past decade.

Doug Kluck, Central Region Climate Services Director, and Kevin Low, Missouri Basin River Forecast Center Hydrologist, share their perspectives about NOAA's involvement in responding to the Missouri River floods of 2011.

During spring 2011, the Northern Great Plains experienced record flooding. This video explains how a La Niña climate pattern helped set the stage for this extreme event.

Molly Heller is part of a team of scientists who processes flasks of air samples in NOAA’s Earth System Research Laboratory in Boulder, CO. Week in and week out, Heller and her colleagues unpack sealed glass flasks shipped back to Boulder from dozens of remote sites around the world. What’s inside is priceless: air captured from a site near Tasmania’s Cape Grim; from Summit, Greenland; the Canary Islands; the South Pole.

The types of tree species that grow in a particular region determine the range of bright colors that paint our landscapes during the fall season. In the future, scientists project that the forest habitats all around us may undergo major changes to due to warming temperatures.

Compared to the large ozone hole that forms over Antarctica each year, Arctic ozone loss has generally been much more limited. But in 2011, Arctic ozone declined to surprisingly low levels. What did climate have to do with it?

In the mid-1980s, the winter sea ice pack in the Arctic was dominated by multi-year ice—ice that had survived at least one summer melt. Today, less than half of the sea ice at winter maximum has survived at least one summer.

The low ice extent recorded this September continued the downward trend seen over the last 30 years. Meanwhile, scientists are finding that the ice cover has grown thinner, making it more vulnerable to melting during the summer.