Sea ice extent in the Arctic in January 2011 was the lowest for any January in three decades of monitoring. Just how much lower than usual? A picture is worth a thousand words.
Observers have also noted an increase in the length of the sea ice melting season. Scientists point toward two contributing factors:
- Atmospheric conditions that pushed cold air south over North America and Europe and allowed warm air to sit over the Arctic.
- Warming due to reduced reflection of sunlight by dark ocean waters revealed when sea ice melts.
Both explanations are examples of the classic circular feedback loops that are so pervasive in climate science. Melting ice leads to Arctic warming, which sets up atmospheric conditions that hold warm air over the Arctic, which leads to further melting, which leads to more warming, which … you get the idea.