Sea Ice

As federal marine mammal experts in Alaska scramble to study how global warming will affect walrus, polar bears and ice seals, they warn there are limit to the protections they can provide. They can restrict hunters, ship traffic and offshore petroleum activity, but they acknowledge there are limits if the animals' basic habitat -- sea ice -- disappears every summer. "Ultimately it's beyond my scope," said Joel Garlich-Miller, a walrus expert for the U.S. Fish and Wildlife Service in Anchorage.

The historic loss of sea ice seen in the Arctic in recent years is tied to widespread warming in the polar region that is increasing at a rate of more than 2 degrees per decade, according to a NASA satellite study released Thursday. Last year, the summer ice that normally clogs Arctic seas was at historically low levels. This summer, the ice remained at near record lows, and the Arctic's largest ice shelf cracked apart.

In what would be the largest habitat zone ever established in the U.S. to protect a species from extinction, the federal government today proposed designating 200,541 square miles on the coast of Alaska as critical habitat for polar bears. Officials said the designation is not likely to further slow the pace of oil and gas development, and it crucially would not impose any controls to slow the biggest threat to polar bears, the melting of sea ice as a result of climate change. Those steps are crucial for polar bears but are being addressed separately in Congress through proposals to cap greenhouse gas emissions, said Tom Strickland, assistant Interior secretary for fish, wildlife and parks.

Anyone forced to shovel their car out of a snowbank this winter might wonder just how it is a blizzard can occur in a warming climate. The answer, climate scientists say, may have to do with record sea ice losses in the Arctic. At a Tuesday news conference, several researchers said that warming conditions in the Arctic may be weakening jet stream currents and causing extreme weather systems to linger in northern mid-latitudes. "Ironically ... as the ice pack retreats and the Arctic heats up, there's a counteracting tendency in middle latitudes for colder winters, as well as hotter summers," said Stephen Vavrus, senior scientist at the Nelson Institute for Environmental Studies at the University of Wisconsin.

If the prospect of coastal cities sinking into the sea 100 years from now does not motivate Americans to do something dramatic to reduce carbon dioxide emissions, there is something happening at this very moment that should be setting off sirens. Rising CO2 levels are making the oceans more acidic and that change in the chemistry of the seas is disrupting the food chain that ends with you and me. For years, as scientists watched the carbon emissions from our tailpipes and smokestacks spew into the sky and goose temperatures higher, there was one mitigating factor that was keeping a brake on global warming: The oceans were absorbing a whole lot of that CO2. Now, though, it turns out that is not such a blessing.

SEATTLE - The federal law listing polar bears as a threatened species was upheld Friday by a federal appeals court, which rejected arguments that it is wrong to impose far-ranging and possibly costly protections for a species that remains fairly abundant in many regions of the Arctic. Concluding that attacks on the listing “amount to nothing more than competing views on policy and science,” the U.S. Circuit Court of Appeals in Washington, D.C., upheld the U.S. Fish and Wildlife Service's 2008 decision to protect the animals because the dramatic loss of sea ice leaves them likely to become in danger of extinction.

Loss of sea ice due to global warming could open new seasonal shipping lanes through the Arctic Ocean by midcentury, sharply reducing transit times and opening a Pandora's box of safety, environmental and legal issues, according to scientists. In a paper published Monday in the Proceedings of the National Academy of Sciences Plus, researchers estimated that new shipping lanes linking the Atlantic and Pacific oceans are likely to open between 2040 and 2059. The lanes would not be open year-round, however, and would likely be restricted to late summer, when ice cover is lowest.

First came the polar bear. Now, the federal government has added two other marine mammals to the list of creatures threatened with extinction because of vanishing sea ice in a warming Arctic. The National Oceanic and Atmospheric Administration has officially listed bearded seal and the ringed seal as threatened under the Endangered Species Act. The reason is not inadequate supplies of fish and other food for these seals, or excessive hunting by humans. It's the loss of their sea ice habitat.

Arctic sea ice is shrinking at a rate much faster than scientists ever predicted and its collapse, due to global warming, may well cause extreme weather this winter in North America and Europe, according to climate scientists. Last month, researchers announced that Arctic sea ice had dwindled to the smallest size ever observed by man, covering almost half the area it did 30 years ago, when satellites and submarines first began measuring it. While the loss of summer sea ice is likely to open up new shipping lanes and may connect the West Coast of the United States to the Far East via a trans-polar route, researchers say it will also affect weather patterns and Arctic wildlife.

There was less sea ice in the Arctic on Friday than ever before on record, and the melting is continuing, the National Snow and Ice Data Center reported. "Today is a historic day," said Mark Serreze, a senior research scientist at the center in Boulder, Colo. "This is the least sea ice we've ever seen in the satellite record, and we have another month left to go in the melt season this year."