Andrew Revkin files another dispatch from Greenland in today's New York Times:

Experts have reported a series of observations in recent months that show that the ice and the waters here are in a state of profound flux. If the trends persist, they could mean higher sea levels and widespread coastal flooding. There is also a small chance that the changes could lead to a sharp cooling in parts of the Northern Hemisphere.

Although nobody expects shifts as rapid or cataclysmic as portrayed in the new movie "The Day After Tomorrow," the cooling could disrupt the relatively stable climatic conditions in which modern human societies have evolved.

Meanwhile, the Integrated Ocean Drilling Program (drilling for research, not oil) is preparing to send the Arctic Coring Expedition (Acex) to the Lomonosov ice ridge between Greenland and Siberia in August to take core samples. This ice is a "very beautiful archive" of data on how long Arctic ice has existed and the impact of the Arctic Ocean on global climate.