Experts from the scientific community and the U.S. Navy came together in Washington this month for three days of talks about the impact of declining Arctic ice. Changes in the polar icecap have raised concerns among researchers and the military.

The far north is still cold and covered with ice in the winter. But more and more ice is melting during the summer. Compare the extent of the icecap in September, at the end of the northern summer. Fifty years ago, ice covered about 8.5 square kilometers. Last year, it was about 5.5 million. That's a decline of about one-third in just half a century.

And Dr. Richard Spinrad, a senior official at the National Oceanic and Atmospheric Administration, NOAA, says the ice is disappearing faster than projected.

"What we are seeing is a dramatic increase in the rate of loss of sea ice," Spinrad stressed. "It's decreasing faster than some of the earlier predictions. And so some of the consequences are now clearly impacting a wide range of commerce issues, a wide range of transportation and resource availability issues."

For example, Coast Guard Rear Admiral Brian Salerno pointed out that less Arctic ice may mean greater access to energy resources in the region.

"There's an estimate by U.S. Geologic Survey that about 25 percent of the world's oil and gas reserves reside in the Arctic region. And so you can anticipate a desire by many nations, many of the Arctic nations in particular, to gain access to those energy reserves."

Rear Admiral Timothy McGee, who heads the Navy's Meteorology and Oceanographic Command, noted that with less ice in the Arctic, new shipping lanes will open up, cutting the distance between Asia and Europe, for instance, almost in half.

"The current transit, if you're going from Tokyo to London is over 11,000 miles [18,000 km]," McGee said. "If you go via the Northwest Passage, it's about 6,000 miles [10,000 km]. It has enormous economic implications. And then there's commerce and competition. Today the Arctic is very much an ecological [undeveloped] zone. It's very safe. Commerce is going to push that to the limit."

You'll notice that the military folks are keeping an eye on these developments since there are likely to be a whole new set of security issues, say experts, as nations compete for energy resources and may assert territorial rights in newly ice-free areas

Meanwhile, scientists continue to study the changes. Satellites provide much of the data used to monitor the extent of sea ice. The satellite observations are supplemented by information gathered by aircraft, and NOAA wants to obtain some new, unmanned aircraft for this purpose. But there's no substitute for data gathered on - and below - the surface. At the National Science Foundation, for example, Dr. Martin Jeffries says they are working with Russia on setting up instruments moored on either side of the Bering Strait.

"So we have moorings in Russian waters as well as in American waters, giving us for the first time, really, a more comprehensive picture of the flow of water from the North Pacific into the Arctic basin, which is of great interest because it's a significant source of heat, flowing into the Arctic basin, and therefore affecting the sea ice," he said.

The study of changes in the Arctic, as well as Antarctic, is a focus of the International Polar Year program. Despite its name, it's actually a two-year effort involving thousands of scientists from 60 countries working together to learn more about the polar regions.