A essay from a reader
No evidence that climate warming is manmade: Then why all the fuss?
By S. Fred Singer *48
In Paris [in February], the UN’s Intergovernmental Panel on Climate Change (IPCC) issued its scientific report on global warming. Its main conclusion was that the current warming trend is “very likely” caused by human activities, principally the release of the greenhouse gas carbon dioxide into the atmosphere from the burning of fossil fuels.
There are three things wrong here. First, the IPCC issued only a “Summary for Policymakers.” This brief document is the result of political negotiations among some 150 governmental delegations, stretching over several days. The actual 800-page scientific report, which few will read, will be issued in May to allow time to make it “consistent” with the summary. So: a political summary first, an adjusted report three months later. Second, the summary projects a future temperature rise that is more modest than that of the previous IPCC report, issued in 2001. It projects a rise in sea level that is roughly half the previous value. To make up for these less severe projections, the hype and propaganda had to be increased; so indeed, some scary scenarios emerged from the IPCC press releases to the media, anxiously waiting for promised disasters.
Finally – and most important – the IPCC ignored sound evidence, readily available in published reports, that contradicts their main conclusion of anthropogenic global warming. In other words, the warming is very likely produced by natural factors, like the sun.
I will try to discuss this complicated issue in a nontechnical manner, relying mainly on logic, and pose three fundamental questions: 1) Is there evidence for or against an appreciable human contribution to current climate warming? 2) Would a warmer climate be better or worse than the present one? And 3) realistically speaking, can we do something about climate? Is it possible to influence the climate by policy actions in an effective way?
First, the climate is always changing – either warming or cooling – on time scales ranging from decades to millions of years. Nearly 20 ice ages have come and gone in the past two million years, controlled by predictable changes in Earth’s orbit and tilt of its axis; our present interglacial warm period is 12,000 years old and may soon end. Geological evidence has also uncovered a 1,500-year climate cycle, likely caused by the sun – and also unstoppable. On top of all this, we have irregular, unpredictable short-term fluctuations. Since 1979, weather satellites have shown a slight warming trend that is well within historical experience. How can we tell whether this recent warming is due to human influences, such as the rise in atmospheric greenhouse gases, or whether it is simply another natural fluctuation?
It’s no use asking the thermometers; they cannot talk. The melting of glaciers and ice sheets, the rise in sea level, severe storms, floods, droughts – all of these are interesting, to be sure, but really irrelevant to our question. They may well be connected to a warmer climate – or maybe not – but they cannot tell us what causes the warming. Nor can a vote among scientists settle this issue. Science is not democratic: History teaches that the majority is quite often wrong. Climate models, run on giant computers, give scary results; but these are simply theoretical exercises – not to be confused with real evidence. Nor can we argue that the rough correlation of current warming with the rising level of greenhouse gases proves a cause-effect relationship. World climate cooled between 1940 and 1975, while energy use and carbon-dioxide (CO2) levels rose sharply. “Correlation is not causation” – a truth that is often forgotten.
So what’s left? All working scientists agree that one must compare the observed patterns of warming with the patterns calculated from greenhouse models and look for “fingerprints” – distinctive geographic and altitude patterns of temperature trends. A recent U.S. government report, using the best available climate models and temperature data, gives a definitive result: Calculated patterns do not agree with observations. (See Figure 5.4G in HYPERLINK "http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm" http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm.)
Logically, even an agreement could not prove that the warming is due to human causes; it only would make it plausible. But when we find a significant disagreement between observations and models, then we can argue that the influence of human effects is minor compared to natural climate fluctuations. This discrepancy also shows us that existing models cannot be used in a reliable way to make predictions about future climate warming – and about its consequences.
The second question is clearly in the realm of economics. The ongoing debate assumes, generally without much analysis, that a warmer climate presents a “danger” or a “threat” – implying serious consequences for economy, human health, ecology, etc. On the other hand, a prestigious group of resource economists, headed by professor Robert Mendelsohn (Yale University), showed positive consequences: The GDP of the United States would increase for assumed modest temperature increases (Cambridge University Press, 1999).
One can also look at historical evidence. We know from voluminous records that human existence was good and more comfortable during the Medieval Warm Period (ca. 1100 AD), when Vikings settled Greenland, than during the following Little Ice Age, when crops failed, people starved, and disease was rampant; life then was nasty, brutish, and short. Another way of tackling this question is to ask if things were better in 1976, when it was colder than today. It soon becomes obvious that climate effects are minor compared to everything else that happened in the last 30 years; but that is exactly the point: Technological progress and the mobilization of capital in a market economy far outweigh any climate factor in promoting prosperity – here and throughout the world. Would a slightly warmer climate, of say one degree C in a hundred years, have serious effects on the way we live, on the economy, human health, or anything else? Indeed, since most agree that a colder climate would damage the economy, one might ask: What is the probability that the present climate just happens to be the Panglossian optimum?
The third topic is perhaps easiest to deal with. People often talk about “stabilizing the climate”; what they really mean is stabilizing the concentration of greenhouse gases in the atmosphere. But even that is a daunting task. It is well known what it would take to stabilize the level of carbon dioxide in the atmosphere: All agree that this requires reducing emissions worldwide by between 60 to 80 percent, including China and India. In practical terms, this calls for reducing energy use from fossil fuels by comparable amounts. It is also agreed by all that the Kyoto Protocol is a puny effort; its effect on climate would be minute: a calculated temperature reduction of only one-twentieth of a degree – not even measurable by ordinary thermometers. Nevertheless, the United States and Australia have faced heavy criticism from other industrialized nations for not joining them in ratifying Kyoto.
But since it is unlikely that the current warming has much of a human component and since it is unlikely that something substantial can be done about reducing CO2 growth – what is the point to a vast program of costly mitigation, when, most probably, a warmer climate would produce positive benefits instead of damages? This is particularly true when huge tangible costs must be incurred today to avoid hypothetical damages in the far future.
Atmospheric physicist S. Fred Singer *48 is professor emeritus of environmental sciences at the University of Virginia. He served as the founding director of the U.S. Weather Satellite Service and as vice chairman of the U.S. National Advisory Committee on Oceans and Atmosphere. His most recent book, Unstoppable Global Warming – Every 1500 Years (Rowman & Littlefield), is on The New York Times bestseller list. This article was submitted to Le Monde March 4, 2007.
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