Antarctic Ice Sheet Mass Balance

[MtnBiker]

FYI

Reference

Wingham, D.J., Shepherd, A., Muir, A. and Marshall, G.J. 2006. Mass balance of the Antarctic ice sheet. Philosophical Transactions of the Royal Society A 364: 1627-1635.
What was done
The authors "analyzed 1.2 x 108 European remote sensing satellite altimeter echoes to determine the changes in volume of the Antarctic ice sheet from 1992 to 2003." This survey, in their words, "covers 85% of the East Antarctic ice sheet and 51% of the West Antarctic ice sheet," which together comprise "72% of the grounded ice sheet.""

What was learned

Wingham et al. report that "overall, the data, corrected for isostatic rebound, show the ice sheet growing at 5 ± 1 mm year-1." To calculate the ice sheet's change in mass, however, "requires knowledge of the density at which the volume changes have occurred," and when the researchers' best estimates of regional differences in this parameter are used, they find that "72% of the Antarctic ice sheet is gaining 27 ± 29 Gt year-1, a sink of ocean mass sufficient to lower [authors' italics] global sea levels by 0.08 mm year-1." This net extraction of water from the global ocean, according to Wingham et al., occurs because "mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica."

What it means

Contrary to all the horror stories one hears about global warming-induced mass wastage of the Antarctic ice sheet leading to rising sea levels that gobble up coastal lowlands worldwide, the most recent decade of pertinent real-world data suggest that forces leading to just the opposite effect are apparently prevailing, even in the face of what climate alarmists typically describe as the greatest warming of the world in the past two millennia or more.

Reviewed 8 November 2006

http://www.co2science.org/scripts/CO2ScienceB2C/articles/V9/N45/C2.jsp

 

[Mr. P]

FYI



http://www.co2science.org/scripts/CO2ScienceB2C/articles/V9/N45/C2.jsp

This net extraction of water from the global ocean, according to Wingham et al., occurs because "mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica.

I can understand equilibrium between east/west. But a gain overall? I don’t get that one.

 

[KarlMarx]

I don't want to hijack the thread, but I have to tell you what happened to me the other day.

Our local paper's website now allows people to post comments on letters to the editor and news stories. Much like we do here on USMB.

So someone wrote in about global warming. I replied, not about global warming itself but more about the Kyoto treaty. I made the comment that whether global warming is caused by Man or not is still hotly debated...

So, a professor from the local university replies and gives all sorts of counter arguments, etc etc. Then, he'd sign his posts with "Professor R, Professor Emeritus, Binghamton University"....

So I assumed that he was a climatologist and studies this extensively. In fact the local paper seems to have asked him to write on the subject of global warming...

What would you assume?

Anyway, someone eventually posted that Professor R is a professor of SOCIOLOGY! I did a Google search on his name and sure enough, he's a professor of sociology, and as far as I can tell does not study climatology, doesn't participate in any meetings with climatologists. He is part of the school of business or public relations...

Now, I don't want to say that Professor R's counterarguments were not well thought out and presented, they were.

But, I do think that it was dishonest of him to throw his title around as if he were an expert on the subject, when his area of study isn't even remotely similar to climatology.

To paraphrase the old line "I'm not a climatologist, but I try to pass myself off as one at the Press & Sun Bulletin's website"

P.S. He did mention a recent study that stated that the "cost of action" to stop global warming would "only" cost 1 to 2 percent of global GDP (Gross Domestic Product), I assume per year.

Then I did a little research

a. Global GDP is over 60 trillion dollars - 1 to 2 percent of 60 trillion dollars is 600 billion to 1.2 trillion dollars a year.

b. The study was funded by an organization that contained "friends of Earth" in its title.... which causes me to suspect just how objective the research is (not very).

c. Since "b" is true, my guess is that the cost of action was severely underestimated, so the real cost of action is probably at least 2 times or more per year (1.2 to 2.4 trillion dollars per year or more).

d. That means, if we try to stop global warming, we are probably going to bankrupt the world economy, cause a global depression and cause millions of deaths in the process....

 

[glockmail]

FYI

....

Nice find. Thanks.

 

[theHawk]

From my post on a similar thread about Global Warming:

A new NASA-funded study finds that predicted increases in precipitation due to warmer air temperatures from greenhouse gas emissions may actually increase sea ice volume in the Antarctic’s Southern Ocean. This adds new evidence of potential asymmetry between the two poles, and may be an indication that climate change processes may have different impact on different areas of the globe.


..........................


Typically, warming of the climate leads to increased melting rates of sea ice cover and increased precipitation rates. However, in the Southern Ocean, with increased precipitation rates and deeper snow, the additional load of snow becomes so heavy that it pushes the Antarctic sea ice below sea level. This results in even more and even thicker sea ice when the snow refreezes as more ice. Therefore, the paper indicates that some climate processes, like warmer air temperatures increasing the amount of sea ice, may go against what we would normally believe would occur.

http://www.nasa.gov/centers/goddard/news/topstory/2005/sea_ice.html

 

[Mr. P]

From my post on a similar thread about Global Warming:

A new NASA-funded study finds that predicted increases in precipitation due to warmer air temperatures from greenhouse gas emissions may actually increase sea ice volume in the Antarctic’s Southern Ocean. This adds new evidence of potential asymmetry between the two poles, and may be an indication that climate change processes may have different impact on different areas of the globe.

That makes sense. Thanks.

 

[bobn]

http://www.co2science.org/scripts/CO2ScienceB2C/articles/V9/N45/C2.jsp

Yes antarctica is cooling in the central region and may overall be gaining ice mass. In any case it is not significantly melting.

But sidetracking from that question for a second, compare the above co2science article with the one I have linked to below, which is also about a study involving antarctica satellite mass measurements, but this study concludes a decrease in ice mass:

http://www.co2science.org/scripts/CO2ScienceB2C/articles/V9/N10/C1.jsp

Now compare the reporting style that co2science uses between both articles. The difference in words they italicize between the two articles is especially revealing.

Here is the abstract of the paper the 1st article discusses to make it clear there were problems found in that study too.

The Antarctic contribution to sea-level rise has long been uncertain. While regional variability in ice dynamics has been revealed, a picture of mass changes throughout the continental ice sheet is lacking. Here, we use satellite radar altimetry to measure the elevation change of 72% of the grounded ice sheet during the period 1992–2003. Depending on the density of the snow giving rise to the observed elevation fluctuations, the ice sheet mass trend falls in the range −5–+85Gtyr−1. We find that data from climate model reanalyses are not able to characterise the contemporary snowfall fluctuation with useful accuracy and our best estimate of the overall mass trend—growth of 27±29Gtyr−1—is based on an assessment of the expected snowfall variability. Mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica. The result exacerbates the difficulty of explaining twentieth century sea-level rise.

Notice the word estimate? I tried not to italicize it.

 

[Said1]

Ok, I'll admit I"m tried, but what is the importance of this

overall, the data, corrected for isostatic rebound

This happens when the ice melts......Oh, I think I figured it out.

 

[SpidermanTuba]

FYI



http://www.co2science.org/scripts/CO2ScienceB2C/articles/V9/N45/C2.jsp

True or not, global sea levels are still rising http://sealevel.colorado.edu/
A gain in mass over 72% of Antartica does not imply a net gain globally.