Mr. President, it has been a privilege.

Arctic Ice Cap Shrank Sharply This Summer, Experts Say

It also appears that the change is becoming self sustaining, with the increased open water absorbing solar energy that would be reflected back into space by bright white ice, said Ted A. Scambos, a scientist at the National Snow and Ice Data Center in Boulder, Colo., which compiled the data along with NASA.

"Feedbacks in the system are starting to take hold," Dr. Scambos said. "The consecutive record-low extents make it pretty certain a long-term decline is underway."