Melting Glaciers Cause Land to Rise in Alaska

"The geology is complex, but it boils down to this: Relieved of billions of tons of glacial weight, the land has risen much as a cushion regains its shape after someone gets up from a couch. The land is ascending so fast that the rising seas — a ubiquitous byproduct of global warming — cannot keep pace. As a result, the relative sea level is falling, at a rate “among the highest ever recorded,” according to a 2007 report by a panel of experts convened by Mayor Bruce Botelho of Juneau.

Greenland and a few other places have experienced similar effects from widespread glacial melting that began more than 200 years ago, geologists say. But, they say, the effects are more noticeable in and near Juneau, where most glaciers are retreating 30 feet a year or more.

As a result, the region faces unusual environmental challenges. As the sea level falls relative to the land, water tables fall, too, and streams and wetlands dry out. Land is emerging from the water to replace the lost wetlands, shifting property boundaries and causing people to argue about who owns the acreage and how it should be used. And meltwater carries the sediment scoured long ago by the glaciers to the coast, where it clouds the water and silts up once-navigable channels."