Startling Disappearance of Arctic Ice Cap ’04-‘06
[ NAT'L GEOGRAPHIC CONTRASTS: 2004 vs 2005 :
2005 Image 2006 Image
INTERPRETING THE ABOVE IMAGES
Black Dot = North Pole
pink = ice cover blue = open water
colours: orange = 70%, yellow = 50%, and green = 30%
In 2005, the uniform grey area in the ASAR image and the pink colour in the AMSR-E image are both consistent all the way around the pole (black hole), indicating pack ice with 100% ice concentration. However in 2006 there is a significant extent of fractures and openings in the sea-ice
Arctic ice cover had disappeared so much last month that a ship could sail unhindered from Europe's most northerly outpost to the North Pole itself. Ice-free sea stretched north of Svalbard, (between Norway and the North Pole) - into the Russian Arctic, all the way to the North Pole.
Perennial sea ice(ice present year-round and not affected by the Arctic summer) had disappeared over an area bigger than the British Isles, ESA said. "This situation is unlike anything observed in previous record low-ice seasons,"
Over the last 25 years polar ice cover has shrunk and thinned, but this year's images are unprecedented, and fierce storms that fragmented and scattered already thin pack ice may be to blame, the scientists believe.
Last week a paper published in Science, found that year-round sea ice in the Arctic shrank by one seventh between 2004 and 2005.
Retreating ice cover creates a vicious circle that traps more of the Sun's heat. Ice, being white, reflects the Sun's rays - less ice and the sea warms, - this accelerates the melting.
The shrinkage of the Arctic icecap disturbs important ocean currents.
"We might see attempts at sailing around the world directly across the summer Arctic Ocean within the next 10-20 years."
Further, 5-10% of the Arctic’s perennial sea ice, which had survived the summer melt season, has been fragmented by late summer storms.
During the last 25 years, satellites have been observed reductions in the minimum amount of ice recorded (at the end of summer) from 8M sqkm (1980’s) to the historic minimum of 5.5M sqkm in 2005. The extent of perennial ice has been rapidly declining, but this strange condition in late August marks the first time it exhibited thinner and more mobile conditions.
Though the reason for the considerable change in the ice pack configuration is still unknown, it is likely due to the stormy weather conditions in August that characterised the month.
The effect stormy conditions have on ice is illustrated in this ASAR image, taken on 25 August 2006, as the ice in the red circle is divergent as a consequence of a low pressure system centred on the North Pole. "As autumn freeze-up begins, the current pattern will undoubtedly precondition the ice situation in the Central Arctic for the subsequent ice season," Drinkwater said.
the thickness of the perennial ice over the Arctic has declined from about 11 feet in the early 1960s to 7 feet or less today. While ice does form over the remaining open water during the winter, that seasonal ice is only about 1 to 5 or 6 feet thick, and breaks up quickly.
WHAT WAS NOT DISCUSSED:
ICE ABSORBS A TREMENDOUS AMOUNT OF HEAT TO MELT (80 calories / gram)
WHEN THE AMOUNT OF ICE DECREASES (OR DISAPPEARS) THAT HEAT WILL INCREASE ARCTIC TEMPERATURES
THIS WILL FURTHER DESTABILIZE PERMAFROST CARBON AND METHANE-HYDRATES
THE INCREASE IN TEMPERATURE WILL ALSO DECREASE THE AMOUNT OF OXYGEN IN THE OCEANS WATERS.