ANCHORAGE, Alaska, Aug. 3 (UPI) -- The Northwest Passage may become ice-free for the second summer in a row, scientists monitoring the situation say.

BOULDER, Colo., June 27 (UPI) -- Ice, for the first time in human history, could disappear from the North Pole this year, scientists say.

BOULDER, Colo., Oct. 2 (UPI) -- A U.S. study shows Arctic sea ice during this year's melting season plummeted to the lowest levels since satellite measurements began in 1979.

BOULDER, Colo., April 5 (UPI) -- A team of U.S. scientists has determined the maximum extent of Arctic sea ice the past winter was the second lowest on satellite record.

BOULDER, Colo., Oct. 4 (UPI) -- A U.S. study suggests 2006 continued the pattern of sharp annual decreases in Arctic ice due to global warming.

CAMBRIDGE, England, March 14 (UPI) -- Scientists, noting sea ice in the Arctic has failed to form for the second consecutive winter, fear global warming may be irreversible in polar areas.

BOULDER, Colo., Sept. 28 (UPI) -- Climatologists say this month will set a record minimum in the amount of Arctic sea ice cover and the ice shrinkage might quicken in the future.

BOULDER, Colo., Sept. 16 (UPI) -- Arctic ice melting may have accelerated to a "tipping point" that will produce a vicious cycle of melting and heating, said U.S. scientists say.

BOULDER, Colo., Nov. 7 (UPI) -- Earth appears to be losing its ice in virtually every form, from glacial peaks to the permafrost frozen deep below ground.