The 2012 summer melt of Arctic sea ice has halted, but the ice pack shrank to record low levels this year and covers only half the area that it did as recently as 30 years ago, scientists announced on Wednesday.
The National Snow and Ice Data Center reported that sea ice in the Arctic Ocean covered 1.32 million square miles as of Sunday, nearly 20 percent smaller than the previous record low of 1.61 million square miles set five years ago.
The ice pack covered only 24 percent of the surface of the Arctic Ocean, compared to 29 percent in 2007. Half of the ocean’s surface was covered when satellite tracking began in the late 1970s.
“Time to act without further dangerous delay,” former Vice President Al Gore tweeted after the report was released.
Mark Serreze, director of the snow/ice center, which is funded by the government, said:
“We are now in uncharted territory. While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur.”
The main question facing scientists is what those changes mean for the rest of the Earth.
Walt Meier, a research scientist at the snow and ice center, told The New York Times: “The Arctic is the Earth’s air conditioner. We’re losing that. It’s not just that polar bears might go extinct, or that native communities might have to adapt, which we’re already seeing — there are larger climate effects.”
The Arctic has experienced global warming at a faster rate than any other place on Earth.
Polar bears have been classified under the Endangered Species Act because of the loss of ice floes from which they hunt seals. Arctic villages, shorn of ice pack protection, have been buffeted by violent late fall/early winter storms. The melting of permafrost has produced listing trees, “drunken forests” that are releasing methane into the atmosphere.
The carbon economy, largely responsible for climate change, has invaded Arctic waters as the United States, Russia and Canada have rushed to explore for gas, oil and minerals.
But the impacts of shrinking ice are likely to be felt far beyond the far north.
Sea ice reflects back more than 90 percent of solar heat, but open water absorbs more than half that amount of heat. Scientists are examining whether this is a cause of the upsurge in violent and extreme weather — and such consequences as spreading fires in the American West.
“The scientific community realizes that we have a planetary emergency: It’s hard for the public to recognize this because they stick their head out the window and don’t see that much going on,” Dr. James Hansen, the NASA climate scientist, told a Greenpeace-sponsored panel in New York.
Led by the National Association of Manufacturers, major U.S. industries have repeatedly tried to block the U.S. Environmental Protection Agency from setting limits on emission of greenhouse gases into the atmosphere.
Republican presidential candidate Mitt Romney, while acknowledging climate change, opposes the EPA working to regulate its causes. Romney was cheered wildly when he made a joke about rising ocean levels in his Republican Convention acceptance speech.
Scientists had forecast that the Arctic ice pack will disappear in summer by the year 2050.
With this year’s rapid melt, they see it happening sooner.