Includes historical analyses, spatial trends, and changes in extremes
Temperatures in Alaska and the Arctic are rising twice as fast as other parts of the U.S. and—except for sea ice—are the most obvious signs of change.
Why? The main reasons are decreases in sea ice and snow cover, warming oceans, and increasing greenhouse gases. Of course, variability exists day-to-day and even year-to-year, depending on average storm tracks, but the trends are unmistakable.