December 8, 2012
Another Global Warming Drive-ByBy Timothy Birdnow
Much ado has been made about the loss of sea ice in the Arctic Ocean by the Gang Green, those global warming hysterics who want us to fundamentally reorganize human civilization based on a statistically marginal temperature rise planetwide in the 20th century. But the Antarctic proved a tougher nut to crack, as Antarctica is a continent surrounded by sea and that continent has been gaining ice. While the North Pole seems a bit soggy for old St. Nick, the South Pole is picking up the slack. (Will the jolly old fellow in the red suit move his base of distribution? He ought to; Obama may want to nationalize it like he has done health care and General Motors.) Clearly, something had to be done about Antarctica.
And that something is the latest act of drive-by consensus science -- the Ice Sheet Mass Balance Inter-Comparison Exercise, or IMBIE. Here is the press release. and here is a typically glowing article trumpeting the IMBIE press release as gospel.
The Ice Sheet Mass Balance Inter-Comparison Exercise is a composite of the last twenty years worth of ice data compiled by NASA and the European Space Agency, and it supposedly shows land ice loss in both Greenland and Antarctica. And IMBIE is a noxiously arrogant exercise, claiming to be the absolute-golly-gee-whillickers-bestest ever study that just happened to find both ice caps over Greenland and Antarctica are melting like a wet Wicked Witch of the West (in this case West Antarctica). But this seems to contradict a lot of solid research. What is happening here?
First, the Yahoo Canada article actually mentions;
"Combining the 20 years of accumulated data from 10 different satellites -- including Canada's RADARSAT-1 mission -- and ensuring that the data was all applied over the same geographic area, using the same time spans, and using the same models for surface melting of glaciers and for the rise of land-mass due to glacial melting (known as post-glacial rebound), the team found that the ice sheets of Greenland and Antarctic have been losing mass at an accelerated rate since the early '90s."
I'm not sure how they square that with the fact that we have not seen increasing planetary temperatures in seventeen of those twenty years. But notice the "models" for surface melting; I was under the impression they were actually supposed to be measuring ice mass itself.
Well, it turns out to be more complicated than that. See, satellites pass over the same places at the same time every day. Also, how do you tell how much ice is over a spot? How do you tell how dense it is? Satellite coverage is far from complete for the whole Arctic or Antarctic, and so models have to be employed and extrapolations made. If ice is seen as disappearing in one spot it is assumed to be disappearing in spots that the satellites aren't getting a good look at. So models have to be used to make that extrapolation. It's part of why the National Snow and Ice Data Center accidentally "lost" Arctic ice -- about 193,000 square miles of it -- when they changed methods a few years back. This was a result of "sensory drift" and algorithmic problems.
And let us not forget that Antarctica is largely covered with ice; these sensors have to determine the mass of the ice based on other factors such as measurements of gravitational anomalies and other tricky things. It's difficult when you are trying to get a side-shot of your target, and trying to take into account factors that are not readily apparent such as land rise (when ice weight is reduced). Dr. Shepherd and the other researchers at IMBIE claim to have taken all this into account, but how accurate is their data?
There is a better way to determine this.
If I may quote from myself in a piece I had at Pajamas Media back in 2008:
"This is interesting because it logically ties in with sea level rise. Sea levels have been rising for the last 10,000 years - since the end of the last ice age - and an increase in ice melt should coincide with an increase in the rate that the sea level is rising.
According to the Intergovernmental Panel on Climate Change (IPCC) report from 2001:
"No significant acceleration in the rate of sea level rise during the 20th century has been detected."
And in 2007 the IPCC reported:
"Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961 to 2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer-term trend is unclear."
(Hat tip: World Climate Report)
According to the University of Colorado, the short-term rate of sea level rise has been leveling off.
Yet Jay Zwally from NASA claims that Greenland has lost 150 gigatons of water - enough to raise sea levels by 5 mm per year.
So, either NASA is right and the IPCC wrong, or the IPCC is right and NASA has blown the data. It should be pointed out that GISS has made serious errors before, including proclaiming 1998 the hottest year on record (they quietly corrected it to 1934 without announcing their error) and releasing September temperature records this year in October, proclaiming it the warmest October on record (until they were caught)."
Now, sea ice melt does nothing to change sea levels, but melting of glaciers and ice caps are a different story, and we should see an acceleration of the rate of sea level rise as this surface ice melts away. (I'm not sure how Antarctic ice can melt given the average temperatures there, but then I suppose some of it could sublimate directly into the dry atmosphere.) But if the Greenland and Antarctic land ice is melting away as these researchers claim we should see an acceleration in the rate of sea level rise. We do not. See here
But the researchers stubbornly persist in claiming an increase in sea level rise from ice melt.
Interesting. So how do they arrive at the conclusions that they do?
Dr.S. Fred Singer, Professor Emeritus at U. of Virginia and current head of the Science and Environment Policy Project, gives us the answer:
55.5 mm or 2.2 inches per century. The international research group of polar scientists, IMBIE, announced that melting glacial ice on Greenland and Antarctica has increased sea levels by 11.1 mm over 20 years, from 1992 to 2011, which can be extrapolated to the numbers above. However, one must not rely on long run extrapolations from short run data.
Yet, IMBIE did so. It stated that sea level rise increased in the second decade over the first decade. What is particularly interesting is the early data shows a decline in sea levels from an accumulation of ice, which indicates a cooling. Yet the 1980s and 1990s were decades of warming.
It is also interesting that news reports, such as in the Washington Post, excitedly reported the polar melt and sea level rise, but failed to provide information on how tiny the rise is. See here (for a graph).
This despite clear evidence that the RATE of sea level rise has not significantly increased.
Three years ago a claim was made that West Antarctica was warming -- and it turned out that the author of the paper (Steig et. al) "smeared" temperatures across the region, mixing warming in the Antarctic Peninsula with the rest of West Antarctica. By redefining regions, and he used the warming during the 1950's to "prove" West Antarctica was warming as a whole. He created a warming trend where none existed. Antarctica underwent considerable warming in the '50's -- well before the acceleration of carbon dioxide rise in the Earth's atmosphere, and the Antarctic Peninsula was and is considerably warmer than the main body of the continent.
The IMBIE report admits that ice is growing in East Antarctica and blames that on Global Warming; warmer air causing increased precipitation. But if that is so why is it not happening in West Antarctica as well? The entire Antarctic continent is surrounded by seas and the circumpolar current keeps the cold water swirling around it. By their own logic their argument falls; a warmer Antarctic would mean more snowfall everywhere, and that would mean we should see MORE ice in West Antarctica.
And if heat is shriveling the ice cap, is it reducing the sea ice packs? It just so happens that Antarctic sea ice extent is at an all time high.
Here is a table of sea ice extent in the Antarctic from NASA's Earth Observatory:
September/February (maximum/minimum) in million square kilometers
1979-2000 mean 18.7 2.9
Interesting; if Global Warming is real we should have seen less sea ice on an ever declining scale.
According to the NASA article:
"Since the start of the satellite record, total Antarctic sea ice has increased by about 1 percent per decade. Whether the small overall increase in sea ice extent is a sign of meaningful change in the Antarctic is uncertain because ice extents in the Southern Hemisphere vary considerably from year to year and from place to place around the continent. Considered individually, only the Ross Sea sector had a significant positive trend, while sea ice extent has actually decreased in the Bellingshausen and Amundsen Seas. In short, Antarctic sea ice shows a small positive trend, but large scale variations make the trend very noisy."
And a 2009 study of Antarctic ice melt (and ice caps have been melting since the end of the Little Ice Age, remember) showed it at it's lowest melt levels, indeed, that ice cap melt levels are negligible.
What about icebergs? Antarctic icebergs form when an ice shelf collapses. (Bergs are different from pack ice, which forms from freezing water on the surface of the ocean.) We should see a clear pattern of change in their numbers and distribution. Antarctic icebergs form when ice calves from one of the many coastal shelves, and there should be more calving off as the continent warms. Yet there does not appear to be a clear change in their distribution -- if anything, there appears to be fewer. See figure 5 and 6 for smaller bergs, which are defined as under 10 nautical miles and compromise 90% of all Antarctic bergs. See larger examples in this pdf -- again figures 5 and 6.
And the Shepherd et. al. (the lMBIE paper) abstract specifically mentions, well, here, read it yourself;
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods -- especially in Greenland and West Antarctica -- and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year-1, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year-1 to the rate of global sea-level rise"
And yet the datasets they combine are notoriously unreliable, according to Yoaz Bar-Sever, R. Steven Nerem, and a number of others at the Jet Propulsion Labs, and a new platform is needed. Anthony Watts covers the issue here. It was problems with this very altimetry, interferometry, and gravimetry that caused the NSIDC to lose that 193,000 miles of ice that I mentioned earlier.
In short, this is a case of garbage in, garbage out. For all of the braggadocio of the IMBIE scientists they actually do not have anything new and are likely not accurate. This is more drive-by consensus science.
But the media has sunk its collective fangs into this and is tearing away. With the Doha talks and the re-election of Barack Obama, the environmental lobby thinks they can revive this issue, and they need some new, spectacular scientific bauble to catch the public eye.
Don't fall for it.
(Hat tip; Daren Jonescu.)
Read more from Tim and friends at www.tbirdnow.mee.nu
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