Thursday, October 11, 2007
The Arctic sea ice is disintegrating "100 years ahead of schedule", having dropped 22% this year below the previous minimum low, and it may completely disappear as early as the northern summer of 2013. This is far beyond the predictions of the International Panel on Climate Change and is an example of global warming impacts happening at lower temperature increases and more quickly than projected. What are the lessons from the Arctic summer of 2007?
Executive summary (Released 8 October 2007)
• Climate change impacts are happening at lower temperature increases and more quickly than projected.
• The Arctic's floating sea ice is headed towards rapid summer disintegration as early as 2013, a century ahead of the International Panel on Climate Change (IPCC) projections.
• The rapid loss of Arctic sea ice will speed up the disintegration of the Greenland ice sheet, and a rise in sea levels by even as much as 5 metres by the turn of this century is possible.
• The Antarctic ice shelf reacts far more sensitively to warming temperatures than previously believed.
• Long-term climate sensitivity (including "slow" feedbacks such as carbon cycle feedbacks which are starting to operate) may be double the IPCC standard.
• A doubling of climate sensitivity would mean we passed the widely accepted 2°C threshold of "dangerous anthropogenic interference" with the climate four decades ago, and would require us to find the means to engineer a rapid drawdown of current atmospheric greenhouse gas.
• Carbon dioxide (CO2) emissions are now growing more rapidly than "business-as-usual", the most pessimistic of the IPCC scenarios.
• Temperatures are now within ≈1°C of the maximum temperature of the past million years.
• We must choose targets and take actions that can actually solve the problem in a timely manner. (more at link)
Meanwhile: Walruses invade Alaska beaches, alarm conservationists
• Thousands of walruses are gathering off Alaska's northwest coast
• The walruses are usually spread over thousands of miles of sea ice
• Conservationists link the change to melting Arctic sea ice
• Biologists fear walrus will suffer nutritional stress
...The immediate concern of new, massive walrus groups for the U.S. Fish and Wildlife Service is danger to the animals from stampedes. Panic caused by a low-flying airplane, a boat or an approaching polar bear can send a herd rushing to the sea. Young animals can be crushed by adults weighing 2,000 pounds or more.
Longer term, biologists fear walrus will suffer nutritional stress if they are concentrated on shoreline rather than spread over thousands of miles of sea ice.
Walrus need either ice or land to rest. Unlike seals, they cannot swim indefinitely and must pause after foraging....