New computer modeling suggests the Arctic Ocean may be nearly ice-free in summer as early as 2014, Al Gore said today at the U.N. climate conference in Copenhagen.

The former vice president said the new projections suggest an almost-vanished summer ice cap could disappear much earlier than foreseen by a U.S. government agency just eight months.

"It is hard to capture the astonishment that the experts in the science of ice felt when they saw this," Gore told reporters and other conference participants at a joint briefing with Scandinavian officials and scientists, his first appearance at the two-week session.

(Posted by Doug Stanglin)

Update at 3:58 p.m. ET: "Some of the models suggest that there is a 75 percent chance that the entire north polar ice cap during some of the summer months will be completely ice-free within the next five to seven years," Gore said.

Afterward his office clarified his statement, saying he meant nearly ice-free, because ice would be expected to survive in island channels and other locations.

Gore cited new scientific work at the U.S. Naval Postgraduate School. The Navy relies on its research to plan submarine voyages to the poles. The computer modeling there stresses the "volumetric" and looks at both the surface extent of ice and its thickness.

In April, the U.S. National Oceanic and Atmospheric Administration predicted that Arctic summers could be almost ice-free within 30 years, not at the 21st century's end as earlier predicted.

(Updated by Michael Winter)