At the Tipping Point

Some part of the Arctic has stayed frozen year-round for the last 800,000 years, at least. But if current melting trends continue, the Arctic Ocean will be ice-free by 2030 -- much sooner than previously thought.

The UK Guardian is reporting that winter sea ice in the Arctic reached an all-time low in March, hastening a trend in which ice recovery in winter is not enough to compensate for the loss of ice in summer.

The Arctic melting trend is self-reinforcing, as the dark ocean surface absorbs solar radiation the ice had previously reflected. Because of this positive feedback loop, scientists fear we may have passed a tipping point, possibly leading to runaway climate change.