23 - 29 August 2001
Issue No.548
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Al-Ahram Weekly Online 23 - 29 August 2001 Issue No.548 |
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Who's talking about what?
Not only do they disagree, they disagree about whether they agree. Al-Ahram Weekly examines the state of the debate among scientists about climate change
There are three separate issues often lumped under the all-purpose heading "climate change." The foundation of the debate is that average temperatures, including figures for land and ocean surface temperatures have risen over the last century. A significant increase in Greenhouse Gas Emissions (GGEs), particularly CO2, has also been recorded. These two facts together have led scientists to conclude that damage to the earth's ozone layer, along with the increased GGEs, are warming the earth. The first observation, which simply recognises a change, is "climate change"; the second deduction from that to a theory of global warming.
Though there are many scientists who question our ability to make this deduction, it is the nexus on which the whole debate about climate change depends. It places the blame for warming squarely on man -- hence implying culpability for all the human suffering caused by changes in weather patterns. The UN framework for climate change (UNFCCC) assumes this culpability and tries to lessen it by controlling emissions in a way that gives ecosystems enough time to adapt and cope with increased temperatures.
According to the Environmental Protection Agency (EPA), global temperatures have gone up between 0.3¡C and 0.6¡C. This roughly concurs with UN Inter-governmental Panel on Climate Change (IPCC) estimates, which suggest a 0.6¡C increase, plus or minus 0.2¡C. Evidence that the earth is warming seems overwhelmingly strong, but some scientists argue that the earth goes through phases and that what is currently dubbed "global warming" is simply part of the natural ebb and flow of the earth's atmosphere -- a worldwide pattern of cooling and heating. And though the scientific community is often lumped into a collective voice heralding the earth's destruction, there are many researchers and climatologists who question the direct relation between GGEs and climate change. These scientists are labelled "sceptics" and are often dismissed as being on the cusp of the scientific community or having a hidden agenda.
The logic of global warming seems difficult to dispute. Even if GGEs did not spark the warming trend, they can only aggravate it. The majority of scientists in the field are persuaded that the evidence linking emissions and warming is incontrovertible. Environmental groups insist that denying human culpability is to persist in wilful ignorance and to resist constructive change in the way human civilisation draws its energy.
But asked about increased disasters due to climate change, S Fred Singer of the Science and Environmental Policy Project was adamant that the media misrepresents scientists as unified in the contention that global warming is a reality, implying that only a few, rogue malcontents depart from this view. "I don't know of any responsible scientist who would link earthquakes, volcano eruptions, etc., to increases in atmospheric greenhouse gases," Singer told Al-Ahram Weekly. "In fact, many scientists are becoming convinced by the data that [global warming] is negligible." This opinion has been echoed by several scientists in the field. MIT climatologist Richard S Lindzen, who took part in a report issued in June by the National Academy of Sciences, said as much last month in his comments published in the US magazine The New American, and environmental scientist Patrick J Michaels wrote a scathing op-ed deconstruction of the myth of scientific consensus in a July issue of The National Review.
Russ Schnell, of the US Climate Monitoring Diagnostic Laboratory (CMDL), admits that not all scientists agree about global warming, but adds that many do. He told the Weekly that there is equal dispute over the effects of CO2 build-up and how it will manifest itself. "But, no scientist disputes that CO2 is increasing faster today than in the past million years or so," Schnell notes. "Climate change has always been part of the natural cycles of earth and atmosphere. It is just that the current CO2-induced change may be faster and more dramatic than has occurred in the past and that man, plants, and animals will not be able to adapt fast enough to handle the change gracefully."
"Mr Singer does not speak for most climatologists," remarked David R Easterling, principal scientist at the NOAA's North Carolina-based National Climatic Data Center (NCDC), the world's largest active archive of weather data. "He chooses only evidence that seems to support his position, ignoring most credible evidence. Most climatologists in climate change research do not think that global warming is 'negligible'. On the contrary it is becoming more clear that climate change is real." Citing the most recent IPCC report -- "a product of many hundreds of scientists actively working in climate research" -- Easterling notes that the evidence is becoming very clear that "humans are impacting the climate, resulting in climate change."
"The science behind the IPCC report is the best available in the field," says Schnell. "There is no doubt that humans have the capability to change climate. Just look at deforestation and desertification. There is debate on how the whole CO2 scenario will play out, but the basic physics of the phenomenon are not in question."
Aubrey Meyer, director of the London- based Global Commons Institute (GCI), agrees. "The laws of physics and thermo- dynamics are universal and apply regardless of the number of people who may or may not recognise them," he told the Weekly. "If the earth had no atmosphere, and therefore no greenhouse gas concentration and warming effect, the planet would be sub-zero temperature at night and above boiling during the day. In these conditions -- as on the moon -- life as we know it would not be possible. The atmosphere, aided by its interactions with the oceans and the biosphere, moderates these extremes. However, the global temperature increases now reported by most serious scientists are a simple result of the uncontested increase of greenhouse gas concentrations in the atmosphere, which result from the uncontested increase of human emissions of these gases."
Simon Torok, of the UK-based Tyndall Centre for Climate Change Research, is equally certain of the case for warming. While he dismisses connections between disasters like earthquakes to global warming, he does suggest that "future increases in severe weather events are likely, and the vast majority of scientists believe climate change is happening and that humans have been a contributing factor."
In an article in The New American, MIT's Richard Lindzen argues that the period of time during which we have studied trends in climate change -- roughly 20 years -- is too short to be able to determine if there is a real threat, or, in fact, anything extraordinary going on. The article also notes that temperatures were similar to present conditions in 1940, and that in the 1970s, people were even worried about a new ice-age. But the NCDC's Easterling rejects this claim, saying that climatologists look at the past 120 years, not 20 years. Refuting the claim that temperatures in the 1940s were much cooler worldwide, Easterling noted that "climate science has advanced a lot since the mid- 1970s, and what was believed then is not relevant today."
"The level of greenhouse concentration in the atmosphere at this time is higher than anywhere in data sets going back half a million years," says GCI's Meyer. "Historically these levels have varied but at significantly lower average value than the levels we have achieved since the industrial revolution began around 200 years ago. It is possible -- perhaps probable -- that continuing this unrelenting pulse of human emissions will trigger global climatic upheaval." Referring to the claim that it is not clear that anything has indeed gone "wrong," Meyer insists, "The point [Lindzen] makes is simply: if there isn't a problem, don't fix it. However, it is obvious that there is a problem, and that we are all going to be broke if we don't fix it."
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