Scientists predict Arctic could be ice-free within decades

Mar 25, 2011 By Nancy Atkinson, Universe Today
Sea ice data through mid- March 2011. Credit: National Snow and Ice Data Center

Bad news for what is now the beginning of the "melt season" in the Arctic. Right now, the sea ice extent maximum appears to be tied for the lowest ever measured by satellites as the spring begins, according to scientists at the University of Colorado Boulder’s National Snow and Ice Data Center. And because of the trend of how the amount of Arctic sea ice has been spiraling downward in the last decade, some scientists are predicting the Arctic Ocean may be ice free in the summers within the next several decades.

“I’m not surprised by the new data because we’ve seen a downward trend in winter sea ice extent for some time now,” said Walt Meier, a research scienitist with the NSIDC.

The seven lowest maximum Arctic sea ice extents measured by satellites all have occurred in the last seven years, and the from the latest data, the NSIDC research team believes the lowest annual maximum ice extent of 5,650,000 square miles occurred on March 7 of this year.

The maximum ice extent was 463,000 square miles below the 1979-2000 average, an area slightly larger than the states of Texas and California combined. The 2011 measurements were tied with those from 2006 as the lowest maximum sea ice extents measured since record keeping began in 1979.

Virtually all climate scientists believe shrinking Arctic sea ice is tied to warming temperatures in the region caused by an increase in human-produced greenhouse gases being pumped into Earth’s atmosphere.

Meier said the Arctic sea ice functions like an air conditioner for the global climate system by naturally cooling air and water masses, playing a key role in ocean circulation and reflecting solar radiation back into space. In the Arctic summer months, sunlight is absorbed by the growing amounts of open water, raising surface temperatures and causing more ice to melt.

“I think one of the reasons the Arctic sea ice maximum extent is declining is that the autumn ice growth is delayed by warmer temperatures and the ice extent is not able to ‘catch up’ through the winter,” said Meier. “In addition, the clock runs out on the annual ice growth season as temperatures start to rise along with the sun during the spring months.”

Since satellite record keeping began in 1979, the maximum ice extent has occurred as early as Feb. 18 and as late as March 31, with an average date of March 6. Since the researchers determine the maximum extent using a five-day running average, there is small chance the data could change.

As of March 22, ice extent declined for five straight days. But February and March tend to be quite variable, so there is still a chance that the ice extent could expand again. Ice near the edge is thin and is highly sensitive to weather, scientists say, moving or melting quickly in response to changing winds and temperatures, and it often oscillates near the maximum extent for several days or weeks, as it has done this year.

In early April the NSIDC will issue a formal announcement on the 2011 maximum with a full analysis of the winter ice growth season, including graphics comparing 2011 to the long-term record.

Explore further: Kiribati leader visits Arctic on climate mission

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omatumr
2.3 / 5 (6) Mar 26, 2011
I do not know if this report has any scientific validity, or if it is just another attempt to use science for government propaganda, but I do know that mankind cannot stop natural changes in Earth's climate.

If the geologic record tells anything, it is that Earth's climate has always been changing - probably because Earth's heat source is a variable star.

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
Skeptic_Heretic
2.3 / 5 (3) Mar 26, 2011
Former NASA Principal
Investigator for Apollo
Ask him why it says 'former'.
MikeyK
3.7 / 5 (3) Mar 27, 2011
Oh Oliver...can we have no more conspiracy garbage please!
GSwift7
5 / 5 (1) Mar 29, 2011
The low extent of this year and last year are mainly due to an unusual, but not rare, wind pattern caused by the location of a semi-permanent low pressure system. The north polar ice cap floats and it will move around in response to wind and pressure systems. When large amounts of ice get moved south, out of the arctic, that ice will not move back into the arctic and it will melt. This year there was a surprising blessing though, as the winds drove the ice pack up against the coast of the Canadian arctic, causing it to buckle and thicken. So although the extent is less, there 'may' be a good thickening this year. The year-round loss of ice due to ice physically moving around for the past two years has been predicted to cause unusually low ice extent for at least the next year or two, maybe longer. This should not surprise anyone who follows news on this site. The situation I'm speaking about was well covered here on this site.
thermodynamics
5 / 5 (1) Mar 29, 2011
GS7: Good observation on the ice situation. However, the data are still subject to interpretation. There are two efforts going on right now to lower the uncertainty in the measurements. The first is a ground survey (boots on the ground) that is measuring thickness across the arctic. Then the other (and more long term) approach is Cryosat 2 which has data available on-line from ESA"

"www.esa.int/esaLP...at.html"

The beauty of Cryosat 2 is that it is making its data available to anyone. Just go get it and analyze it. This will limit the conjecture about all of the ice on the planet and start giving us a check on the older methods of measurement. The next few years will be interesting. The first order of business is to find out how earlier measurements correspond to Cryosat when they are running in parallel. Then the older methods can be corrected. The next order of business is to use all methods to see what is really happening.