The shock came when the International Polar Year, a global consortium studying the Arctic, froze a small vessel into the sea ice off eastern Siberia in September 2006. Norwegian explorer Fridtjof Nansen had done the same thing a century before, and his Fram, carried by the drifting ice, emerged off eastern Greenland 34 months later. IPY scientists thought their Tara would take 24 to 36 months. But it reached Greenland in just 14 months, stark evidence that the sea ice found a more open, ice-free, and thus faster path westward thanks to Arctic melting.

The loss of Arctic sea ice “is well ahead of” what the Intergovernmental Panel on Climate Change forecast, largely because emissions of carbon dioxide have topped what the panel—which foolishly expected nations to care enough about global warming to do something about it—projected. “The models just aren’t keeping up” with the reality of CO2 emissions, says the IPY’s David Carlson. Although policymakers hoped climate models would prove to be alarmist, the opposite is true, particularly in the Arctic.

The IPCC may also have been too cautious on Greenland, assuming that the melting of its glaciers would contribute little to sea-level rise. Some studies found that Greenland’s glacial streams were surging and surface ice was morphing into liquid lakes, but others made a strong case that those surges and melts were aberrations, not long-term trends. It seemed to be a standoff. More reliable data, however, such as satellite measurements of Greenland’s mass, show that it is losing about 52 cubic miles per year and that the melting is accelerating. So while the IPCC projected that sea level would rise 16 inches this century, “now a more likely figure is one meter (39 inches) at the least,” says Carlson. “Chest high instead of knee high, with half to two-thirds of that due to Greenland.” Hence the “no idea how bad it was”.

... contd.