The Truth About Global Warming

If this official verdict on climate change seems bad enough, the real story could be far worse. The summary is extremely conservative in that it is a consensus on what is known with certainty, and so can be defended against all challengers. It was written this way to make it unassailable by the skeptics and by governments looking for an excuse for inaction.

But dozens of climate scientists, including many of the leading lights on the IPCC, are deeply concerned about potential positive feedbacks not yet included in current models of the Earth’s climate system. These could significantly accelerate global warming. They include physical collapse of the Greenland ice sheet, rapid melting in Antarctica and release of the major greenhouse gases carbon dioxide and methane from melting permafrost, soil, and the ocean bed. The impact of these phenomena on warming would be huge and so scientists came together to discuss these dangers at a conference two years ago at Exeter organized by the UK government. Before describing those dangers it’s useful to investigate why the IPCC had to shield its report from some skeptics, supported by Big Coal and Big Oil, and from a few key Republican members of Congress. 

No doubt the timidity of the IPCC is at least partly the result of a sustained and debilitating attack on leading climate scientists One example was given in an editorial last year in Science, published by the American Association for the Advancement of Science. Editor-in-Chief Donald Kennedy cites letters by then-Chairman of the House Committee on Energy and Commerce Joseph Barton (R-TX) sent to a number of scientists. Among them were Dr. Rajendra Pachauri, chairman of the IPCC; Dr. Arden Bement Jr., director of the National Science Foundation; and research professors Drs. Michael F. Mann, Malcolm K. Hughes, and Raymond S. Bradley, who had collaborated on analysis of global temperature data.

The text of each letter begins with a brief summary of the conclusions of the IPCC regarding human influences on global warming. Then after reciting some reasons for skepticism about these conclusions and Mann’s role in them, it lists an extraordinarily burdensome set of demands, including disclosure of all funding sources, agreements regarding that support, exact computer codes, location of data archives used, responses to refereed criticisms of the work, and the results of all temperature reconstructions. The letter to Mann contains highly specific requests spanning eight paragraphs and nineteen subparagraphs. Bement’s letter demands exhaustive lists of all grants related to climate research, policies relating to IPCC review, information regarding requests for access to research records, and more. Kennedy’s editorial bears the head "Silly Science on the Hill," but his concern goes deep: "It’s clear that what’s going on here is harassment," he concludes.

The Barton letters are part of an attack on research on global warming, a subject especially high on the list of targets of some members of Congress and their business allies. The petroleum industry has spent an enormous amount of money setting up think tanks and sponsoring "contrarian" scientists far outside the mainstream to raise doubts about global warming and its causes. No one has been more supportive of these industry efforts than Senator James Inhofe (R-OK), a leading figure on environmental issues when, until recently, chairman of the Environmental and Public Works Committee. It was Inhofe who went all out to defeat Senators John McCain (R-AZ) and Joseph Lieberman’s (D-CT) Climate Stewardship Act, which would have created the first caps on greenhouse gas emissions ever agreed to by the US government. He succeeded, in part, by stacking a Senate panel with climate science contrarians.

Another of Inhofe’s major accomplishments to date is an extensive speech he gave on the Senate floor entitled "The Science of Climate Change." It outlines conclusions he says he reached after several years of studying the issue. The talk ends with the suggestion, widely quoted, that global warming caused by human activity might be "the greatest hoax ever perpetrated on the American people."

Like these and other steady assaults on the work of the IPCC, the sponsorship of contrarian scientists has had an unjustifiably large impact. In the early 1990s Big Coal and Big Oil mounted a campaign of disinformation designed to persuade policymakers, the media, and the public that the issue of human-induced climate change was mired in scientific uncertainty. The fossil fuel lobby launched an intense public relations operation featuring the contrarians. Although most of them had little standing among climatologists, they served the purpose of the lobby well by raising doubts about the science in order to preempt public demand for action. The success of this strategy is reflected in two polls conducted by Newsweek magazine: in 1991 35 percent of the people surveyed thought that global warming was a very severe problem; by 1996 that 35 percent had dropped to 22 percent, even though the evidence for global warming and its effects had grown substantially.

Ironically, one way in which the popular media aided the lobby was by the application, superficially and fallaciously, of what is considered good journalism. The effectiveness of the contrarians was because the media, in the name of journalistic balance, accorded them the same weight as the overwhelming body of mainstream scientists. Equal balance may be fine in a story involving opinion but it’s completely misleading in a case like global warming where the evidence comes down so strongly on one side.

More than fifteen years of this heavily funded disinformation assault has made the IPCC overly cautious in reporting on climate change. Among the critically important items ignored in its summary is the physical collapse of the Greenland ice sheet, rapid melting in Antarctica, and the release of the major greenhouse gases carbon dioxide and methane from melting permafrost, soil and the ocean bed.    

At Exeter scientists reported that the huge ice sheets of Greenland and Antarctica could be close to disintegration, which would cause a rise in sea level that would be measured in meters, not inches. Current climate models assume that the ice sheets will melt only slowly, as heat works its way down through ice more than 2 kilometers thick. But many glaciologists no longer believe that this is what will happen.

In reality, they say, ice sheets fracture as they melt, so water can penetrate to the bottom of the ice relatively quickly, warming its full depth and lubricating the boundary between ice and bedrock. In this way, physical breakup of the ice sheets will happen long before thermal melting.

Richard Alley, a US glaciologist who has published widely notes that the rate of ice loss in Greenland has unexpectedly doubled in the past decade. "Our chapter of the [IPCC] report will say that Greenland is doing things that could make it disintegrate much faster than people think," Alley says. "But we don’t have a strong basis yet for projecting exactly what the ice sheets will do." So, he says, the report summary excludes the new thinking.

In February another IPCC author, Stefan Rahmstorf of Germany‘s Potsdam Institute for Climate Impact Research, published a paper showing that world sea levels are rising 50 percent faster today than predicted in the previous IPCC report in 2001. Co-author Jim Hansen of NASA’s Goddard Institute for Space Studies believes this is the first sign of a dramatic acceleration of sea level rise in the coming decades as ice sheets start to disintegrate.

The IPCC consensus also sidelined findings from the British Antarctic Survey. According to the journal New Scientist BAS researchers found that the Antarctic Peninsula is warming faster than almost anywhere on the planet. They’ve confirmed a sharp decline in sea ice around the peninsula and they warn that the huge West Antarctic ice sheet is "unstable and contributing significantly to sea level rise."

Release of greenhouse gases from melting permafrost, potentially an enormous positive feedback, is a real wildcard in the carbon cycle. According to a study by Hansen another decade of business-as-usual carbon emissions will probably make it too late to prevent the ecosystems of the north from triggering rapidly accelerating climate change. Measurements show that central Siberia has warmed by almost 2 degrees Celsius since 1970 – that’s three times the global average. Air temperatures in the Alaskan interior have risen by 2 degrees Celsius since 1950 and permafrost temperatures have risen by 2.5 degrees. 

The release of carbon dioxide by the melting permafrost will be partially offset by greening — new growth vegetation — in the region. But melting of permafrost also releases methane, a "powerful" greenhouse gas, so the net effect is a large positive feedback. Hansen’s paper concludes that the effects could be huge. "In past eras, the release of methane from melting permafrost and destabilized sediments on continental shelves has probably been responsible for some of the largest warmings in the Earth’s history," he says. Potential release of greenhouse gases from Siberia and the Arctic, too, failed to make it into the IPCC summary.

The people of the world and their governments, local and national, are slowly becoming aware of the dangerous experiment being run on the planet. Nevertheless, carbon dioxide, for example, is accelerating in the atmosphere at a record rate, with annual increases now a third greater than even 20 years ago. Unless we move fast to reverse this danger the Earth will become a very different planet than the one we now know.