Arctic may be clear of ice by summer 2013

[Chris Coles]

This very simple, forget forecasts of the arctic not being clear of ice before the next century; it might be clear by the summer of 2013.

In effect, what is happening is that while it might seem that the surface area is not dramatically declining, the thickness is. The average thickness of the multi-year ice is 3 metres.

"First year ice is now the dominant ice type in the Arctic"

Arctic ice: Less than meets the eye: 25 August 2010 by Chris Mooney
http://www.newscientist.com/article/...s-the-eye.html

"....... the average volume of Arctic ice between July and September has fallen from 21,000 cubic kilometres in 1979 to 8,000 (7,958) cubic kilometres in 2009. That is a 55% fall compared with the 1979 to 2000 average."

[Diarmuid]

Re: Arctic may be clear of ice by summer 2013

It is all a big guessing game - not to say anything of trying to attribute these changes natural or otherwise to trace gas concentrations in the atmosphere.

Article abstract

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Nature Geoscience
Published online: 15 August 2010 | doi:10.1038/ngeo938
Simultaneous estimation of global present-day water transport and glacial isostatic adjustment

Xiaoping Wu¹, Michael B. Heflin¹, Hugo Schotman^2,3, Bert L. A. Vermeersen², Danan Dong¹, Richard S. Gross¹, Erik R. Ivins¹, Angelyn W. Moore¹ & Susan E. Owen¹

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Abstract

Global water transport between oceans and continents during the transition from glacial to interglacial times has been enormous. The viscoelastic solid Earth has been responding to this unloading of large ice masses with a rise of the land masses, in a process termed glacial isostatic adjustment. In addition, significant changes in the land/ocean water distribution occur at present. As both present-day changes in the ice/water thickness and glacial isostatic adjustment affect space geodetic measurements, it is difficult to untangle the relative contributions of these two processes. Here we combine gravity measurements and geodetic data of surface movement with a data-assimilating model of ocean bottom pressure to simultaneously estimate present-day water transport and glacial isostatic adjustment. We determine their separate contributions to movements in the geocentre, which occur in response to changes in the Earth’s mass distribution, with uncertainties below 0.1 mm yr⁻¹. According to our estimates, mass losses between 2002 and 2008 in Greenland, Alaska/Yukon and West Antarctica are 104±23, 101±23 and 64±32 Gt yr⁻¹, respectively. Our estimates of glacial isostatic adjustment indicate a large geocentre velocity of −0.72±0.06 mm yr⁻¹ in the polar direction. We conclude that a significant revision of the present estimates of glacial isostatic adjustments and land–ocean water exchange is required.

Top of page

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1. Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 238-600, 4800 Oak Grove Drive, Pasadena, California 91109, USA
2. DEOS, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, Delft, 2629 HS, Netherlands
3. SRON Netherlands Institute for Space Research, Sorbonnelaan 2, Utrecht, 3584 CA, Netherlands

Correspondence to: Xiaoping Wu¹ e-mail: Xiaoping.Wu@jpl.nasa.gov

[Starving Steve]

Re: Arctic may be clear of ice by summer 2013

This very simple, forget forecasts of the arctic not being clear of ice before the next century; it might be clear by the summer of 2013.

In effect, what is happening is that while it might seem that the surface area is not dramatically declining, the thickness is. The average thickness of the multi-year ice is 3 metres.

"First year ice is now the dominant ice type in the Arctic"

Arctic ice: Less than meets the eye: 25 August 2010 by Chris Mooney
http://www.newscientist.com/article/...s-the-eye.html

"....... the average volume of Arctic ice between July and September has fallen from 21,000 cubic kilometres in 1979 to 8,000 (7,958) cubic kilometres in 2009. That is a 55% fall compared with the 1979 to 2000 average."

We have strong La Nina (cold water) conditions in the world, especially in the Eastern Pacific, in both hemispheres. We are observing warm water and a strong monsoon in the Western Pacific, both hemispheres. These conditions will disappear next year (12 months from now) when the 3rd year of the El Nino commences. The current La Nina conditions are common to the 2nd year of the El Nino, that is to say that 2nd year El Nino conditions revert back to La Nina conditions. The second year is often the abaration year in the El Nino cycle.

Here on the west coast of North America, we have been colder than normal. Surface sea temps are colder than normal in both hemispheres.

We also have low solar energy output plus volcanic dust in the upper atmosphere from Iceland. This will likely cause colder than normal temperatures, especially in the Arctic.

We also have new ice conditions, about one season of thickness. Ice was thinnest and most scant in the Arctic Ocean in 2008 or 2007. Conditions were opposite in the Antarctic where ice was widespread, especially on land and especially thick.

There is no "new science" to any of this. And no "ecosystems" (whatever that word means in traditional science) have been endangered on planet Earth. Nothing has changed because everything on Earth always is changing. The climate pattern is unchanged, and the cycles of the Madden-Julian Oscillation and the El Nino-La Nina Cycle are still in play. We are slowly recovering from the Ice Age 10,000 years ago, with a very very slight warming still detectable, about 0.5 degrees F per century at San Francisco Airport. Sea level is rising about 7 inches per century--- hardly anything to lose sleep over.

[c1ue]

Re: Arctic may be clear of ice by summer 2013

Except for one little problem: the "trend" is not continuing:



Dr. Richard Lindzen has also pointed out that the temperature behavior in the Arctic isn't a shift of the spectrum upwards, it is primarily a shift of higher low temperatures (i.e. in the spring and fall) with summer temperatures being the same:

Lindzen Arctic temperatures 2.PNG

Lindzen Arctic temperatures 1.PNG

Just for the record, summer ice depends mostly on how much is blown out of the arctic basin - something that used to be textdbook information.

http://wattsupwiththat.files.wordpre...tland_2010.pdf

[Diarmuid]

Re: Arctic may be clear of ice by summer 2013

Except for one little problem: the "trend" is not continuing:

To be fair C1ue I believe the article was refering to volume rather then extent.

Just for the record, summer ice depends mostly on how much is blown out of the arctic basin - something that used to be textdbook information.

the study I noted previously Wu et al. report that both Greenland and Antarctica are losing ice-mass, they are doing so at a much lower rate than previous guesstimates, additional they report the Artic is gaining ice in the interior.




Unfiltered GIA geoid height trends. In the figure a, shows rates guesstimated in the study, b,those predicted by the ICE-5G/IJ05/VM2 model.

The mass loss in Greenland is concentrated along the coastal areas, and is particularly heavy in the west, and in the southeast with the large Kangerdlugssuaq and Helheim glaciers,” ..... “In contrast, the interior of Greenland shows significant positive mass balance.

[Starving Steve]

Re: Arctic may be clear of ice by summer 2013

For decades, it has been known that the interior of Antarctica and the interior of Greenland are net ice volume producers, and the Arctic Ocean and Southern Ocean are net ice volume losers. My under-graduate adviser at UC Berkeley in the Geography Dept, Dr. Mario Giovinetto, did the pioneering ice-core measurements, by hand, back in the 1960s.

Dr. Giovinetto found that ice moved from producing areas to the losing areas by a process of ice-flow apparently due to gravity. The process of transfer of ice from land to sea is through calving--- which is the actual break-off of chunks of ice from glaciers to the sea.

So what "new scientists" are doing now is re-discovering old news about the Earth's ice budget. Dr. Giovinetto published his ice budget studies decades ago in the 1960s.

Geographers should be getting the good jobs at NASA and NOAA, not just computer modellers and not just ecologists.

[cmalbatros]

Re: Arctic may be clear of ice by summer 2013

Some interesting articles here - http://www.iceagenow.com/index.htm