Behavior of World's Glaciers Fails to Prove Global Warming Theory
by John Carlisle
Global warming theory proponents have resorted to the politics of fear to drive their point home. They argue that man-made greenhouse gases are already causing the world's glaciers to melt, causing sea levels to rise and threatening humanity with a multitude of economic and environmental calamities. A recent Smithsonian Institution exhibit on climate change, for instance, included a depiction of the Washington Monument partially submerged in the Atlantic Ocean, leaving visitors with the distinct impression that we must reduce greenhouse gas emissions now if we want our descendants to be able to visit the famous monument. But such scenarios belong in the realm of science fiction, not science fact.
Glaciers Are Inaccurate Barometers of Climate Change
Global warming theorists argue that examples of receding glaciers, primarily those located in the mid-latitude regions of the planet, provide evidence that climate change caused by human activities is underway. But glaciers are poor barometers of global climate change.
Glaciers are influenced by a variety of local and regional natural phenomena that scientists do not fully comprehend. Besides temperature changes, glaciers also respond to changes in the amount and type of precipitation, changes in sea level and changes in ocean circulation patterns.1 As a result, glaciers do not necessarily advance during colder weather and retreat during warmer weather.
A major obstacle to linking glacial behavior to global warming is that mountain glaciers, the types of glaciers found in places like Switzerland and the United States, are especially difficult to understand due to the complex topography of mountain areas. Furthermore, Global Climate Circulation Models (GCMs) used by global warming theory proponents to forecast future climate, including the climate's effect on glaciers, have been notoriously inaccurate. NASA scientist James Hansen, the man who helped ignite the global warming debate in the United States in the late 1980s, admitted last year that it was impossible to come up with reliable climate models because there is too much about the climate that scientists don't understand.2
Those same inaccurate GCMs have been even less reliable when it comes to assessing the impact of warming on mountain glaciers. According to Professor Martin Beniston of the Institute of Geography at the University of Fribourg, Switzerland, "Numerous climatological details of mountains are overlooked by the climate models." This makes it difficult to predict the consequences of global warming on glaciers. Beniston says it is "difficult to estimate the exact response of glaciers to global warming, because glacier dynamics are influenced by numerous factors other than climate, even though temperature and cloudiness may be the dominant controlling factors. According to the size, exposure and altitude of glaciers, different response times can be expected for the same climatic forcing."
That may explain why there are several Swiss glaciers that are advancing even though Switzerland has experienced a decade of mild winters, warmer summers and less rainfall.3
Other scientists agree that it is unwise to look to glaciers for evidence of global warming. Keith Echelmeyer, a glaciologist at the University of Alaska's Geophysical Institute, says, "To make a case that glaciers are retreating, and that the problem is global warming, is very hard to do... The physics are very complex. There is much more involved than just the climate response." Echelmeyer points out that in Alaska there are large glaciers advancing in the very same areas where others are retreating.4
Dr. Richard Alley of Pennsylvania State University agrees that the response of glaciers to global temperatures can be difficult to predict. "Glaciers do odd things sometimes," observes Alley. "They flow fast, then slow down... You could anthropomorphize [apply human characteristics to] them and say they have a mind of their own."
Vice President Al Gore would have done well to remember this point before he held a major press conference in 1997 announcing that the century-long retreat of the Grinnel Glacier in Montana's Glacier National Park was caused by global warming.
Size appears to be one of the most significant determinants in the response time of glaciers to climate change. Basically, the larger a glacier, the longer it takes to be affected by climate change. For example, it would take a polar ice sheet 10,000-100,000 years to respond to any global warming that might be occurring now. A large mountain glacier would take 1,000 to 10,000 years to respond to warming today, while a small mountain glacier would take 100 to 1,000 years to respond.5 Thus, one explanation for some glaciers retreating today is that they are responding to natural warming that occurred either during the Medieval Warm Period in the 11th century or to an even warmer period that occurred 6,000 years ago.
Global warming theory proponents point to the retreat of glaciers in the mid-latitude regions of the planet - areas where the United States, Europe and Africa are located - as evidence of human-induced global warming. As mentioned above, these mid-latitude glaciers cannot be used as reliable indicators of global climate change given that they are affected by a complex mixture of local and regional phenomena. By focusing so much attention on these glaciers, however, one gets the distinct impression that global warming theory proponents are deliberately picking glaciers to analyze that support their thesis that global warming is underway while ignoring those glaciers that don't support their theory.
In May 1998, for example, scientists at the University of Colorado at Boulder released a study purporting to show that glaciers are in headlong retreat due to global warming. According to one of the study's authors, Professor Mark Meier: "In the last century, there has been a significant decrease in the area and volume of glaciers, especially at mid- and low-latitudes... The disappearance of glacier ice is more pronounced than we previously had thought." To support this claim, Meier noted that Africa's Mount Kenya had lost 92% of its mass over the last 100 years while Spain's glaciers had fallen in number from 27 in 1980 to just 13 today.6
Because glaciers respond to a variety of phenomena and glaciers in warmer regions tend to be more susceptible to these phenomena, it is unwise to point to a loss of ice volume in vulnerable mid-latitude glaciers to draw ambitious conclusions about alleged warming worldwide.
More important, any melting of mid-latitude glaciers that has occurred has had little effect on sea levels. This is because mid-latitude glaciers represent a mere 6% of the world's total ice mass while Antarctica and Greenland glaciers represent the other 94% of the ice mass. As even the University of Colorado study noted, there is no evidence that
the glacial ice sheets in Antarctica and Greenland are melting. Nevertheless, the study suggested that alleged melting of the mid-latitude ice was enough to cause a major sea level increase because the water from mid-latitude glaciers would be "recycled more quickly" than water from polar glaciers.7 This conclusion is suspect, however, since some of the glaciers in the mid-latitude region are advancing and glaciers currently in retreat could very easily start advancing again. The fact that mid-latitude glaciers are not uniformly retreating coupled with the fact that they represent only 6% of the world's glacial ice strongly argues against the claim that these glaciers are contributing to a rise in sea level. If there is going to be any major sea level increase, it is going to have to come from the melting of the Antarctica and Greenland ice sheets.
Although the Colorado study did not allege that the Antarctic ice sheets are in retreat, other global warming proponents have made such claims. This is understandable from their perspective since a theoretical meltdown of the world's ice caps has the potential to scare the public into supporting major reductions in greenhouse gas emissions.
According to the West Antarctic Ice Sheet Study, a project of the National Science Foundation, if all of the world's ice melted, the sea level would rise by 235 feet.8 NOVA, the Corporation for Public Broadcasting's science program, estimates that the melting of the Antarctic ice sheets alone would raise the oceans by 187 feet. One hundred seventy feet of this rise would be caused by the melting of the East Antarctic Ice Sheet while just 17 feet of this rise would be caused by melting of the West Antarctic Ice Sheet. But the East Antarctic Ice Sheet is considered stable and not threatened by warming because it rests on land above sea level, making any significant sea level rise unlikely.9 The West Antarctic Ice
Sheet, however, has attracted the attention of global warming theory proponents because it rests mostly below sea level where it is allegedly more sensitive to any global warming that may occur.10 The balance of scientific evidence suggests that the West Antarctic Ice Sheet isn't melting either.
To begin with, the Antarctic is extremely cold with a high average temperature of just -56°F. Even if the Antarctic temperatures did rise a few degrees, they wouldn't be high enough to melt the glaciers as the temperatures would still be well below - 87°F below - freezing. The latest GCMs predict warming of just 1-3°F by 2100, still leaving the Antarctic bitterly cold. Furthermore, the Antarctic ice sheet is very large, and thus it takes a long time for the ice sheet to respond to warming. For instance, it would take the West Antarctic Ice Sheet 50,000 years to react to any warming that may be occurring now - so the world is not in any imminent danger of a catastrophic flood.11
So what does the scientific evidence say about a human-induced shrinking of the Antarctic today?
In December 1998, an international team of scientists announced that after analyzing five years of satellite radar measurements, they concluded that the West Antarctic Ice Sheet is not melting rapidly. The scientists determined that the West Antarctic Ice Sheet has actually been stable for the last 100 years - precisely when global warming theory proponents insist human-induced warming should have been causing the glaciers to retreat. Dr. C.K Shum, an Ohio State University professor who participated in the study, said that while the team assumed that global warming was underway, they found no evidence that this purported warming was affecting the Antarctic ice sheet.12
In October 1998, the British Antarctic Survey also announced that it had found no evidence of global warming on the continent. The study noted that it did find 3-4°F of warming on the Antarctic Peninsula over the last 50 years, but that there was no evidence that this localized warming was the result of global warming. The scientists believed it more likely that the origins of the warming "could be found in regional mechanisms."
The survey also analyzed the behavior of two major ice shelves, the Ross and Filchner-Ronne shelves, for any retreat. Again, the study concluded that "it is no longer clear that the small warming that is predicted to result from anthropogenic emissions of greenhouse gases is likely to cause a retreat" of those ice shelves. On the more vulnerable West Antarctic Ice Sheet, scientists likewise concluded that the "dramatic vision of a rapid collapse of the West Antarctic Ice Sheet resulting from atmospheric warming is becoming less acceptable."13
The Antarctic Cooperative Research Centre, a scientific union of the Australian Antarctic Division, the Bureau of Meteorology, the Australian Geological Survey Organization, and the University of Tasmania, released a position statement in April 1997 announcing that it is "very unlikely" that the Antarctic ice sheet will melt enough to cause a significant rise in sea level. Even more interesting, the report stated that over the next one to two centuries, "it is probable that greater snowfall on Antarctica" will outweigh any loss of ice due to warmer ocean water - thus causing the Antarctic ice sheet to expand.14
The prospect that the Antarctic ice sheet is expanding was also noted by the British Antarctic Survey. The British scientists concluded that it is possible that the Antarctic expansion was actually counteracting a rise in sea level.15 Indeed, many other scientists have concluded that even if the world continues to get warmer, whether human-induced or naturally, the Antarctic ice sheet would grow because warming increases the amount of precipitation which leads to increased snowfall in the polar regions.
Indeed, it seems that historically the Antarctic glaciers have frequently expanded during warm conditions. A study by E.W. Domack, A.J.T. Jull and S. Nakao on the history of glacial expansions in Antarctica found that over the past 10,000 years, several glaciers expanded during conditions that were a lot warmer than today.
This uncomfortable fact has not escaped the attention of environmentalists, some of whom are now arguing that glacial expansion supports the global warming theory. Greenpeace's Climate Impacts Database now cites the Domack study in an effort to link the expansion of the Antarctic ice cap with man-made global warming. The summation of the study notes that "the new data suggest strongly that Antarctica's response to future warming will be an increase in mass balance."16 Of course, now they can't claim that the sea level is rising since expansion lowers the level. Nevertheless, environmental groups still make contradictory claims about apocalyptic sea level rises in their haste to mobilize public opinion to stop greenhouse gas emissions.
Like the Antarctic, the Greenland ice sheets show no evidence of receding due to alleged global warming. The record shows that the Arctic region where Greenland is located is cooling despite the fact that, under global warming models, it should be the first area of the planet to show significant temperature increases. According to these models, the polar regions should have warmed 2-5°F since 1940. But between 1955 and 1990, the Arctic cooled by 1°F and Greenland's glaciers actually expanded. According to the scientific journal Geophysical Research Letters, the West Greenland Ice Sheet, the largest mass of polar ice in the Northern Hemisphere, has thickened by up to seven feet since 1980.17
Furthermore, some scientists believe that atmospheric circulation, not temperature, has been the greatest influence on the accumulation of snow and ice in central Greenland for the past 18,000 years. In an article that appeared in Nature magazine in 1995, the authors explained that changes in the way storms move across the island play the key role in how glaciers will thicken or recede.18
There is no indication that the world's glaciers are melting significantly due to global warming and, thus, there is little to fear from sea level rises in coming decades. Proponents of the global warming theory have been irresponsible in attempting to use glaciers as barometers of global temperatures since glaciers respond to a range of natural phenomena that have nothing to do with global temperature changes. In addition, the advance of the Antarctic and Greenland glaciers, which contain more than 90% of the world's glacial ice, completely contradicts previous predictions that warming would cause these glaciers to retreat. Far from providing scientific proof of global warming, the behavior of glaciers represents yet another powerful indictment of the already controversial global warming theory.
John K. Carlisle is director of The National Center for Public Policy Research's Environmental Policy Task Force.
1 Dr. Martin Beniston, "Climatic Change and its Consequences for Mountain Regions," Institute of Geography, University of Fribourg, Switzerland, 1996.
2 "NASA's Hansen Recants on Warming," Electricity Daily, November 19, 1998.
4 "Gore's Defense of Glacier Tourism Trivializes Global Warming Debate," press release, Science and Environmental Policy Project, September 2, 1997.
5 "How Do Glaciers Deal With Environmental Change?" article downloaded January 21, 1999 from the GLACIER web site of the National Science Foundation at http://www.glacier.rice.edu/land/5_glaciersandtheir2.html.
6 "World's Glaciers Continue to Shrink," press release, University of Colorado at Boulder, May 26, 1998.
8 "What is the West Antarctic Ice Sheet," article downloaded January 19, 1999 from the GLACIER web site of the National Science Foundation.
9 "Water World," NOVA Online, Warnings From the Ice, downloaded January 19, 1999 from http://www.pbs.org/wgbh/nova/warnings/waterworld/.
10 "What is the West Antarctic Ice Sheet," article downloaded January 19, 1999 from the GLACIER website of the National Science Foundation at http://www.glaciers.rice.edu/misc.whatisglacier.html.
12 "West Antarctic Ice Sheet Not In Jeopardy," Environmental News Network, December 1, 1998.
13 "Antarctica: Climate Change and Sea Level," Ice and Climate Division, British Antarctic Survey, Cambridge, UK, October 1998.
14 "Global Change, Antarctica and Sea Level," Position Statement, Antarctica Research Centre, April 1997.
15 "Antarctica: Climate Change and Sea Level," Ice and Climate Division, British Antarctic Survey, Cambridge, UK, October 1998.
16 Advance of East Antarctic Outlet Glaciers during the Hypsithermal," E.W. Domack, A.J.T. Jull and S. Nakao, Summary downloaded January 6, 1999 from Greenpeace Climate Impacts Database, http://184.108.40.206/~climate/database/records/zgpz0774.html.
17 Patrick Michaels, "Post Fans Administration's Pre-Kyoto Fires," World Climate Report, December 13, 1997.
18 "Dominant Influence of Atmospheric Circulation on Snow Accumulation in Greenland over the Past 18,000 Years," W.R. Kapsner et. al., Summary downloaded on January 21, 1999 from the web site of the Global Change Research Information Office at http://www.gcrio.org.
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