It’s been known for some time that the ice sheet in the arctic is thinning. And now, a new study (PDF) by the Arctic Monitoring and Assessment Program lays this out in grim detail.

The report lists 15 key findings about the changes at the Earth’s northern regions. Fifteen. Here are four that alarmed me particularly:

1) The past six years (2005–2010) have been the warmest period ever recorded in the Arctic. Higher surface air temperatures are driving changes in the cryosphere.

3) The extent and duration of snow cover and sea ice have decreased across the Arctic. Temperatures in the permafrost have risen by up to 2 °C. The southern limit of permafrost has moved northward in Russia and Canada.

7) The Arctic Ocean is projected to become nearly ice-free in summer within this century, likely within the next thirty to forty years.

12) Loss of ice and snow in the Arctic enhances climate warming by increasing absorption of the sun’s energy at the surface of the planet. It could also dramatically increase emissions of carbon dioxide and methane and change large-scale ocean currents. The combined outcome of ...