Do the arithmetic

A good friend sent me a web page on glaciers and ice sheets. It is based on data from several government and UN sources. The web page sponsor is an environmental non-profit.

Either no one proofread the material or they didn't know arithmetic. I suspect the latter is true of most believers in global warming.

The web page doesn't give data on the portion of the global ice sheet that is in Greenland, but for the combined Greenland and Antarctica ice sheets they claim 30 million cubic kilometers of ice.  Greenland is roughly 2 million square kilometers and Antarctica is about 13 million. Greenland is 15% the size of Antarctica. Greenland is probably less than 4 million cubic kilometers of ice, by using those two numbers.

The image on the right shows the additions and subtractions from the Greenland ice sheet annually. The web page claims that there is a net decrease of 53 cubic kilometers of ice per year in Greenland. They are talking about 53 cubic kilometers out of 4 million cubic kilometers. The idea that anyone could measure 53 cubic kilometers of net ice melt per year (.00001, one hundred thousandths of the total) is absurd. 

The further idea that this incredibly insignificant amount of ice from the net melt of Greenland could create a trend of .005 inch per year rise in the oceans is even more absurd. That would be .5 inch in a century. Half an inch increase in a century in oceans that already vary with tidal action by 45 inches twice a day every day is quite hard to picture as a global danger.

Comments

[hpd]

The study cited suffers from a fundamental flaw that all experimental scientists try to avoid. When performing a difficult experiment, what one wants is a complete rejection of background noise, and only signal detection. Something like turning a light on and off. That is easier to measure accurately. Any errors associated with the measurement of "no signal" can be compensated for, and a similar error assumed or compensated for when measuring the signal.

What one wants to avoid is measuring two very big signals, and them subtracting them to get the difference, particularly if that difference is small. If either of those measurments are off even slightly, that error will swamp the small difference. Each of the individual large measurements may have been taken very accurately, but that may not be good enough.

Just to belabor it: say you measure "big number A + signal" of 10000, to an accuracy of 5 (10,000+/-5 - every time you repeat the exact same measurment you get a value between 10005 and 9995). Then you measure "big number A without the signal" and get a value of 10002. Now, if the actual signal value is 1, there is no way that you can subtract your 2 measurements and claim you measured the difference. It's swamped by your noise.

MP's original point is that this study suffers from trying to detect a small difference between two very large (inaccurate) numbers.

[M. Phillips]

I saw the same material but have not bothered to check the original source. I find that the data on Greenland was focused on the amount of ice melt and runoff but there was no focus on the amount of ice added in the inner ice forming regions.

That may also be true of the Antarctic. Does the data include the amount of ice added on the inner regions?

[Old friend Charlie]

Here's a story to warm MP's heart, if not the planet.

George Taylor is the official state climatologist (paid by the state) for Oregon, Here's what Taylor says about recent studies of Antarctic ice melt that many scientists suggest constitute the proverbial red flag: "The Antarctic is really a puzzle . . . A lot more research is needed to understand the degree of climate and ice trends in and around the Antarctic."

I first heard Taylor speak on the subject (in a radio interview carried on the Southern Oregon University radio station, 'Jefferson Public Radio') about two or three years ago. His position was then (and I guess still is) that there is not clear evidence as to the cause of global warming or even as to global warming itself. He considered global warming to be a possibility but advocated reactive rather than proactive measures.

Taylor has been accused of being in the pockets of 'Big Oil'. In defense against that accusation, Taylor said that he personally rides his bicycle to work and back in Salem, Oregon.

My source on the recent studies of Antarctic ice melt is the March 2 (2006) Washington Post --

http://www.washingtonpost.com/wp-dyn/content/article/2006/03/02/AR2006030201712.html

I love one quote from that article - it encapsulates the entire dispute. So I'll put it in context, from the WaPo article:

< The new findings, which are being published today in the journal Science, suggest that global sea level could rise substantially over the next several centuries.

< The new Antarctic measurements, using data from two NASA satellites called the Gravity Recovery and Climate Experiment (GRACE), found that the amount of water pouring annually from the ice sheet into the ocean -- equivalent to the amount of water the United States uses in three months -- is causing global sea level to rise by 0.4 millimeters a year. The continent holds 90 percent of the world's ice, and the disappearance of even its smaller West Antarctic ice sheet could raise worldwide sea levels by an estimated 20 feet.

< Richard Alley, a Pennsylvania State University glaciologist who has studied the Antarctic ice sheet but was not involved in the new research, said more research is needed to determine if the shrinkage is a long-term trend, because the new report is based on just three years of data. "One person's trend is another person's fluctuation," he said.>

So there it is: "ONE PERSON'S TREND IS ANOTHER PERSON'S FLUCTUATION'.

But then the WaPo article continued quoting the same guy, Richard Alley, like this:

< "It looks like the ice sheets are ahead of schedule" in terms of melting, Alley said. "That's a wake-up call. We better figure out what's going on.">

>Greenland is roughly 2 million square kilometers and Antarctica is about 13 million. Greenland is 15% the size of >Antarctica. Greenland is probably less than 4 million cubic kilometers of ice, by using those two numbers.

You are conviniently forgetting the fact that the Antartic ice is much thicker than the artic ice hence using the ratio of areas to arrive at the figure of 4 million cubic kilometers dosent work out. Moreover the rate of ice melt is increasing each year.

Don't underestimate the destructive potential of a sealevel rise of 0.5 inch.

[Old friend Charlie]

The conflation of politics and science doesn't help me at all. Frankly, I am not much interested in the liberal/conservative controversy. It's become pretty stale over the past 50 years, since William Buckley first decided to pervert the meaning of the word 'conservative' in order to demonize 'the liberals'. Does anyone really care about that anymore? (Maybe if I lived in San Francisco, I could get excited about it, but I doubt it.)

As for the scientific questions, the data are incomplete but indicative of over-all planetary warming. Some (like 'mamapajamas') assign that to increased solar energy input (more activity on the sun), while others see a correlation with industrialization and human population growth. That's theoretically susceptible to quantification, but it's obviously a very complex determination or calculation.

It isn't clear to me whether MP is denying that there is (in 20-year spurts or otherwise) a global warming trend or whether he is simply denying that the cause of that warming is industrialization over the same period of time or earlier. Those are two distinguishable, although interrelated, questions.

While MP's arithmetic is admirable, it doesn't prove that the measurements on the Greenland ice are inaccurate. In today's world, measurements of parts per billion are routine.

Anyway, as for the web page cited, the Greenland ice sheet is only the "tip of the iceberg" - metaphorically speaking. Many other types of ice are discussed, notably "ice shelves" --

< Ice shelves occur when ice sheets extend over the sea, floating on the water. In thickness they range from a few hundred meters to over 1000 meters. Ice shelves surround nearly all of the Antarctic continent. Retreating ice shelves MAY provide indications of climate change.> (My caps added.)

http://www.solcomhouse.com/icecap.htm

NOTE THE WORD 'MAY'. That 'MAY' is seen frequently when I seek objective information about the human factor in global warming. (Of course, political questions are always settled with absolute precision and certainty, if you just know the 'right' answer!)

For example the 'MAY' occurs at the end of the quote, infra, about the question of whether the warming is human-caused. Here it is: on the melting of the arctic ice SHELVES (as distinguished from the Greenland and Antarctic ice SHEETS) from the lndependent/UK (September 24, 2003) --

< "Climate Change Blamed as Largest Arctic Ice Shelf Breaks in Two After 3,000 Years" by Michael McCarthy

< The largest ice shelf in the Arctic, a solid feature for at least 3,000 years, has broken in two and climate change is to blame, say American and Canadian scientists. [NOTE: 'climate change' doesn't imply 'human caused'.]

< The largest ice shelf in the Arctic, a solid feature for 3,000 years, has broken up, scientists in the United States and Canada said on September 22, 2003. They said the Ward Hunt Ice Shelf, on the north coast of Ellesmere Island in Canada's Nunavut territory, broke into two main parts, themselves cut through with fissures. A freshwater lake drained into the sea, the researchers reported.

< Reporting in the journal Geophysical Research Letters, the scientists say the fracture, which had been developing since 2000, was further evidence of continuing and accelerating climate change in the north polar region.

< Much evidence suggests that the sea ice covering the Arctic Ocean is rapidly thinning and retreating, with reports two years ago that at one stage the North Pole itself was actually seawater rather than ice.

< The break-up of the ice shelf - floating ice attached to land - shows a relatively rapid temperature rise. The ice, which formed a cap at the end of the 20-mile long Disraeli fjord, was the largest remaining piece of an ice shelf that once ran the length of Ellesmere Island.

< It began to break up 100 years ago and by 1982 about 90 per cent of it was gone, but it then stabilized over the next two decades, say the scientists, Warwick Vincent and Derek Mueller of Laval University in Quebec City, and Martin Jefferies of the University of Alaska at Fairbanks.

< However, in April 2000, satellite images showed the beginnings of cracking from the eastern side of Ward Hunt Island into the fjord, and by 2001 it had split along its length, then widened in 2002 to 85 yards in some places.>

< The Ward Hunt shelf was up to 100ft thick, far thicker than the sea ice on the Arctic Ocean's surface, which averages 10ft.

< The researchers said its disintegration seemed to have been prompted by a century-old local warming trend, and a more recent rapid rise in temperatures. They were not certain it was linked to the man-made warming apparently caused by rising concentrations of greenhouse gases, but it was one of many signs the Arctic is seeing enormous climatic changes.

< "We believe it's part of a long-term process," said Dr Vincent, a biologist in polar ecology. "But the most recent changes are substantial and correlate with this recent increase in warming seen from the 1960s to the present. A critical threshold has been passed."

< "It is accepted that should the global climate start to warm, the effects would be felt first in the polar regions, and they would be amplified," said Dr Jefferies, a geophysicist.

< "This could be part of that signal." Recent records show there has been a local increase of 0.4 degrees C every decade since 1967. Since then the average July temperature has been above freezing, at 1.3C.

[NOTE THIS DISCUSSION OF THE HUMAN FACTOR]

< Professor Julian Dowdeswell, director of Britain's Scott Polar Research Institute in Cambridge, said the break-up of Ward Hunt ice shelf was not caused by man-made climate change, but by the natural end of a period known as "the little ice age". But he said recent changes in sea-ice thickness and extent could be manifestations of global warming, and the break-up of Ward Hunt could be part of that pattern.>

http://www.commondreams.org/cgi-bin/print.cgi?file=/headlines03/0924-06.htm

So how am I doing? I don't own any equity instruments at all, not counting real estate. I believe that there is global warming, but I think that the causes of it cannot be defined at this time. I may, possibly, approximately, be 50% in agreement with the seven tenets of Lefty Fundamentalism, but mostly that list leaves me with more questions than clarity - especially if I try to apply the criteria to myself. For example, what on earth is meant by this statement --

< People would not be poor if they were given reasonable financial assistance.>

I mean - what does "reasonable" mean in that context? Presumably, it means enough money that they wouldn't be poor any more! Of course, they might be poor again after a while - but that's another discussion, isn't it?

I'll never get it right. Better I should chant.

Nam-myoho-renge-kyo

[Patrick]

Whether it's significant or not is debatable, I suppose, (this was a ten year NASA/ University of Kansas study done between 1996 and 2005), but as for how anyone would measure it, according to NASA (http://tinyurl.com/b2sg6), "...the scientists measured ice velocity with interferometric synthetic-aperture radar data collected by the European Space Agency's Earth Remote Sensing Satellites 1 and 2 in 1996; the Canadian Space Agency's Radarsat-1 in 2000 and 2005; and the European Space Agency's Envisat Advanced Synthetic Aperture Radar in 2005. They combined the ice velocity data with ice sheet thickness data from airborne measurements made between 1997 and 2005, covering almost Greenland's entire coast, to calculate the volumes of ice transported to the ocean by glaciers and how these volumes changed over time. The glaciers surveyed by those satellite and airborne instrument data drain a sector encompassing nearly 1.2 million square kilometers (463,000 square miles), or 75 percent of the Greenland ice sheet total area."

Also, your numbers are a bit off. According to the study, it's "estimated the ice mass loss resulting from enhanced glacier flow increased from 63 cubic kilometers in 1996 to 162 cubic kilometers in 2005. Combined with the increase in ice melt and in snow accumulation over that same time period, they determined the total ice loss from the ice sheet increased from 96 cubic kilometers in 1996 to 220 cubic kilometers in 2005."

Certainly, if the rate of ice loss doubled every ten years, there would be a significant environmental impact (far enough away that it wouldn’t bother me, much, but my kids and any grandkids they may come up with might be in trouble). It's the rate of change, and its variability over time, that’s at issue. Apparently many scientists found this study interesting, because the ice loss is actually more rapid than models had predicted. Glaciologists (interesting line of work that had never occurred to me) think this study is important because it helps to fill in a piece of the puzzle as to why other glaciers (in South America's Patagonia region as well as Alaska and Antarctica have been shrinking more rapidly).

Again, whether it’s significant or not (or an indicator of climate trends) is something everyone can decide for themselves.