Antarctica ice cap is growing , not shrinking?

[The_Flying_Dutchman]

In a recently locked GQ thread I provided the following reply to a statement by the OP

@xtisme

I told him that empirically we know the temperature is on the rise because we can see the effect in the global melting of glaciers (his response was something told to him in church that the ice in Antarctica is actually growing, which is, afaik, complete BS).

see http://www.usatoday.com/news/science/cold-science/2002-01-18-wais-thicker.htm
I didn’t quote from the link as I didn’t want to start a debate in GQ but I will now do so.

But new flow measurements for the Ross ice streams, using special satellite-based radars, indicate that movement of some of the ice streams has slowed or halted, allowing the ice to thicken, according to a paper in the Jan. 18 issue of the journal Science.

If the thickening is not merely part of some short-term fluctuation, it represents a reversal of the long retreat of the ice, say researchers Ian Joughin of the California Institute of Technology and Slawek Tulaczyk of the University of California, Santa Cruz.

Their finding comes less than a week after a separate paper in Nature reported that Antarctica’s harsh desert valleys — long considered a bellwether for global climate change — have grown noticeably cooler since the mid-1980s.

I’m perplexed that this isn’t getting a lot more attention. Is it time for scientists and Al Gore to stop telling us that the Antarctica ice cap is shrinking ?

[RTFirefly]

@The Flying Dutchman

In a recently locked GQ thread I provided the following reply to a statement by the OP

see http://www.usatoday.com/news/science/cold-science/2002-01-18-wais-thicker.htm
I didn’t quote from the link as I didn’t want to start a debate in GQ but I will now do so.

I’m perplexed that this isn’t getting a lot more attention. Is it time for scientists and Al Gore to stop telling us that the Antarctica ice cap is shrinking ?

I could find no date on the linked article, but it’s got a 2002 copyright on it.

Maybe this has been contradicted by more recent data?

[JohnT]

The URL implies it was written on January 18th, 2002.

[Czarcasm]

A January 2002 article from USAToday about a single study that includes this final line:

But he warned that coastal property owners should not become too optimistic about the findings, since the instrumental record is short and coastal ice streams have changed periodically over the centuries.

isn’t really a strong argument in favor of global cooling.

[Bridget_Burke]

Can you find another, more recent source for the story?

[Marley23]

I remember hearing a few years ago that Antarctica is getting colder due to changing wind patterns. IF that’s true, and I don’t know that it is, thicker ice wouldn’t be surprising. Must every piece of ice on Earth get smaller for Al Gore’s theory to be true?

[Tapioca_Dextrin]

It’s entirely possible that those dry valleys will one day be warm enough to grow cherry trees. This will come in handy for folks who want to cherry pick data.

Climate is not the same as weather, and global climate change is not the same as micro climate change.

An increase in snowfall certainly sounds like it’s getting colder, and might well be true if that snow fall blanketed Florida with ten foot high drifts, but we’re talking about Antarctica here. The only way to get more snow is to have more moisture in the air. The only way to do this is to have a warmer ocean.

cite

As others have said, the article cited was from 2002. More recent data shows that overall, Antarctica is actually losing ice. Also, Greenland is losing ice at three times the rate of Antarctica.

[Public_Animal_No.9]

From the IPCC Fourth Assessment: (2007)

Key regional projections highlighted in the TAR
• Increased melting of Arctic glaciers and the Greenland ice
sheet, but thickening of the Antarctic ice sheet due to
increased precipitation, were projected.
(snip)

The TAR is the IPCC Third Assessment Report.

In West Antarctica, there is a suggestion that the dramatic recent thinning of the ice sheet throughout theAmundsen Sea sector is the result of recent ocean change (Payne et al., 2004; Shepherd et al., 2004), but as yet there are too few oceanographic measurements to confirm this interpretation. Indeed, there is evidence that deglaciation of some parts of West Antarctica, as a response to climate change at the end of the last glacial period, is not yet complete (Stone et al., 2003). There are still competing theories, but the now clear evidence of ice-sheet change, has reinvigorated debate about whether we should expect a deglaciation of part of the West Antarctic ice sheet on century to millennial timescales (Vaughan, 2007). Studies based on satellite observations do not provide unequivocal evidence concerning the mass balance of the East Antarctic ice sheet; some appear to indicate marginal thickening (Davis et al., 2005), while others indicate little change (Zwally et al., 2005; Velicogna andWahr, 2006;Wingham et al., 2006).

Although there is disagreement about the future of the Antarctic ice sheet, that does not at all mean that global warming is not real. The details of how global warming will impact different regions are still being studied and debated. There is really no viable debate about whether global warming is occurring - it is - despite the on-going scientific discussions of what is likely to happen at the regional scale.

[The_Flying_Dutchman]

@Czarcasm

A January 2002 article from USAToday about a single study that includes this final line: isn’t really a strong argument in favor of global cooling.

That is not the issue I want to present. Is the Antarctica ice sheet shrinking or not?

There’s a lot of buzz on google (if you look for it) suggesting the ice cap here is actually growing but all I can reference to is blogs refering to studies, that were reported in 2005 and more recently by Hannity who I’ve heard of but assume he’s not highly respected around here.

The gist of the matter as I can best understand it, is that most of the popular scientific studies and claims for Antarctica shrinking center on the peninsula and ignore the rest of the continent. In fact I’ve also read that global warming is responsible for increased precipitation resulting in the mass of the overall ice sheet to increase.

[Jophiel]

@The Flying Dutchman

In fact I’ve also read that global warming is responsible for increased precipitation resulting in the mass of the overall ice sheet to increase.

That was my understanding (to whatever extent). Antartica is a desert because it’s simply too cold for precipitation to reach the center and snow which does get there doesn’t melt and return to the atmosphere. If it’s snowing enough in Antartica for there to be a notable increase in the thickness of the interior, that’d seem to support a warming theory rather than detract from it. Especially combined with the melting of some ice shelves on the edges.

[Marley23]

@The Flying Dutchman

There’s a lot of buzz on google (if you look for it) suggesting the ice cap here is actually growing but all I can reference to is blogs refering to studies, that were reported in 2005 and more recently by Hannity who I’ve heard of but assume he’s not highly respected around here.

To me, that suggests Hannity is trying to discredit global warming theories by reporting the Antarctica information out of context. But maybe I’m too suspicious. :rolleyes:

[Jophiel]

Ok, and for some real data rather than my guesses… Here’s an abstract from the June 2007 Journal of Climate ("Increasing Antarctic Sea Ice under Warming Atmospheric and Oceanic Conditions. ") which I dug up with my college’s journal search engine.

Estimates of sea ice extent based on satellite observations show an increasing Antarctic sea ice cover from 1979 to 2004 even though in situ observations show a prevailing warming trend in both the atmosphere and the ocean. This riddle is explored here using a global multicategory thickness and enthalpy distribution sea ice model coupled to an ocean model. Forced by the NCEP–NCAR reanalysis data, the model simulates an increase of 0.20 × 10^12 m^3 yr^-1 (1.0% yr^-1) in total Antarctic sea ice volume and 0.084 × 10^12 m^2 yr^-1 (0.6% yr^-1) in sea ice extent from 1979 to 2004 when the satellite observations show an increase of 0.027 × 10^12 m^2 yr^-1 (0.2% yr^-1) in sea ice extent during the same period. The model shows that an increase in surface air temperature and downward longwave radiation results in an increase in the upper-ocean temperature and a decrease in sea ice growth, leading to a decrease in salt rejection from ice, in the upper-ocean salinity, and in the upper-ocean density. The reduced salt rejection and upper-ocean density and the enhanced thermohaline stratification tend to suppress convective overturning, leading to a decrease in the upward ocean heat transport and the ocean heat flux available to melt sea ice. The ice melting from ocean heat flux decreases faster than the ice growth does in the weakly stratified Southern Ocean, leading to an increase in the net ice production and hence an increase in ice mass. This mechanism is the main reason why the Antarctic sea ice has increased in spite of warming conditions both above and below during the period 1979–2004 and the extended period 1948–2004.