For scientists, global warming is a disaster movie, its opening scenes set at the poles of Earth. The epic already has started. And it’s not fiction.
The scenes are playing, at the start, in slow motion: The relentless grip of the Arctic Ocean that defied man for centuries is melting away. The sea ice reaches only half as far as it did 50 years ago. In the summer of 2006, it shrank to a record low; this summer the ice pulled back even more, by an area nearly the size of Alaska. Where explorer Robert Peary just 102 years ago saw “a great white disk stretching away apparently infinitely” from Ellesmere Island, there is often nothing now but open water. Glaciers race into the sea from the island of Greenland, beginning an inevitable rise in the oceans. [complete article]
Scientists sometimes refer to the effect a hotter world will have on this country’s fresh water as the other water problem, because global warming more commonly evokes the specter of rising oceans submerging our great coastal cities. By comparison, the steady decrease in mountain snowpack — the loss of the deep accumulation of high-altitude winter snow that melts each spring to provide the American West with most of its water — seems to be a more modest worry. But not all researchers agree with this ranking of dangers. Last May, for instance, Steven Chu, a Nobel laureate and the director of the Lawrence Berkeley National Laboratory, one of the United States government’s pre-eminent research facilities, remarked that diminished supplies of fresh water might prove a far more serious problem than slowly rising seas. [complete article]