Polar bears were declared a threatened species by the US government today, ending a court battle over protecting the animals from melting sea ice caused by climate change. The Bush administration was given a deadline of tomorrow to decide on protecting the bears after environmental campaigners filed a lawsuit. Yet US officials remained defiant in warning that the bears' status was not intended to help regulate emissions in the Arctic.

Polar bears may get more attention

The Arctic and Antarctica are poles apart when it comes to the effects of human-fuelled climate change, scientists said on Friday: in the north, it is melting sea ice, but in the south, it powers winds that chill things down. The North and South poles are both subject to solar radiation and rising levels of climate-warming greenhouse gases, the researchers said in a telephone briefing. But Antarctica is also affected by an ozone hole hovering high above it during the austral summer.

The polar bear has become an icon of global warming vulnerability, but a new study found an Arctic mammal that may be even more at risk to climate change: the narwhal. The narwhal, a whale with a long spiral tusk that inspired the myth of the unicorn, edged out the polar bear for the ranking of most potentially vulnerable in a climate change risk analysis of Arctic marine mammals.

There may be more to global warming than we thought. On top of the effect of human-made carbon emissions, natural changes in the warm ocean currents travelling to the icy north may be helping to heat up the entire northern hemisphere.

The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming the Arctic, and fluctuations of regional fresh water inflow into the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence.

The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, the researchers find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high latitude land areas during the second half of the 20th century.

Rising sea levels, melting river ice seen in Arctic Canada VANCOUVER, British Columbia

This month, NASA begins the most extensive field campaign ever to investigate the chemistry of the Arctic's lower atmosphere. The mission is poised to help scientists identify how air pollution contributes to climate changes in the Arctic. The recent decline of sea ice is one indication the Arctic is undergoing significant environmental changes related to climate warming. NASA and its partners plan to investigate the atmosphere's role in this climate-sensitive region with the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign.

Canadian Researchers Warn Of New Arctic Worries CANADA: April 4, 2008 VANCOUVER, British Columbia - Canada's massive Mackenzie Delta is feeling the impact of climate change faster than expected and could foretell of problems elsewhere in the Arctic, a Canadian researcher said on Thursday. Melting ocean ice is apparently allowing larger storm surges to flood into the delta in Canada's far north, a change that could have an impact on energy development plans for the region, said Lance Lesack, who has been tracking environmental changes in the region for more than a decade.

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