The ongoing American Geophysical Union meeting is full of cheery news. According to a report in the IHT, more than 2 trillion tons of landlocked ice have melted since 2003 in Greenland, Antarctica, and Alaska. Of that, more than half occurred in Greenland, and satellite measurements confirm that the melting is accelerating.
The new results follow on James Hansen's earlier work based on data, rather than models, suggesting that both warming and sea level rise are likely happen faster than the IPCC consensus estimates (see "It's time to Invest in Water Wings"), because the IPCC models explicitly exclude the effect of ice sheet movement and landlocked ice melting.
It gets even better. Reduced sea ice coverage is also now strongly affecting the thermal balance of the poles:
As sea ice melts, the Arctic waters absorb more heat in the summer, having lost the reflective powers of vast packs of ice. That absorbed heat is released into the air in the autumn. That has led to autumn temperatures in the last several years that are 6 degrees Fahrenheit to 10 degrees (3.5 degrees to 6 degrees) warmer than they were in the 1980s.
Warming of the land and sea are coupled: "The loss of sea ice warms the water, which warms the permafrost on nearby land in Alaska, thus producing methane," itself a potent greenhouse gas, according to Julienne Stroeve, a research scientist at the National Snow and Ice Data Center in Boulder, Colorado. (See my previous posts: "Methane Time Bomb" and "Update".)
With respect to the anomolously high Arctic temperatures, The Independent's Steve Connor wonders "Has the Arctic melt passed the point of no return?":
The phenomenon, known as Arctic amplification, was not expected to be seen for at least another 10 or 15 years and the findings will further raise concerns that the Arctic has already passed the climatic tipping-point towards ice-free summers, beyond which it may not recover.
The coupling of land and sea warming constitute a feedback mechanism that threatens to create runaway warming and increased methane emissions, which will only make things worse. Only more data will help resolve any remaining uncertainty. While we gather that data, our time to fiddle is running out.