TCS Daily

Bush is Right on Global Warming, not that reporters would understand

By James K. Glassman - June 29, 2001 12:00 AM

Climate, Richard Lindzen of MIT fondly reminds us, always changes. It must. Over centuries, responding to stresses internal and external, the earth is either warming or cooling, just as the temperature from day to day heats or chills. It could stay the same, but not for very long. "Climate change," then, is not a calamity but a truism.

Evidence from ice cores, glaciers, boreholes and tree rings, deposits of microscopic animals on the sea floor, pollen in lake beds, and mineral deposits in caves show clearly that surface temperatures in some centuries have been very different from temperatures in others. From roughly 800 until 1200 a.d., for example-during what's called the Medieval Warm Period-the Northern Hemisphere became so hot that the Vikings cultivated Iceland, Greenland, and Newfoundland. By the 1300s and 1400s, a widespread cooling had begun that devastated Europe with shortened crop-growing seasons, and human lifespans fell by 10 years. That "Little Ice Age" persisted until the late 19th or early 20th century. Such major climate swings occurred long before the industrial age. More important, the earth's cycles of warming and cooling predate human existence-not to mention sport-utility vehicles.

But, in the view of the people we all "calamitologists," it is man-especially modern man-who despoils nature, stomping around in the Garden of Eden, killing rare species, dumping slop in the streams, and, in a final flourish, turning this beautiful green planet into an oven. A footnote on page 9 of "Climate Change Science," the study released in early June by the National Academy of Sciences, addresses just this issue: "While the activities of mankind are part of the natural world, the convention exists in most discussions of the atmosphere that 'natural processes' are those that would still exist without the presence of human beings."

And what are these unnatural humans up to now? They are spewing more and more carbon dioxide into the atmosphere. As CO2 rises, it tends to prevent some energy from escaping to space. If the climate system does not shed that extra energy, the buildup of CO2 in the air could enhance the largely natural greenhouse effect. Eventually, goes this scenario, the planet gets so warm that icecaps melt, malarial mosquitoes swarm, and droughts starve the inhabitants.

To head off such a putative catastrophe, a protocol signed in Kyoto, Japan, in December 1997 required industrial nations to reduce their emissions of greenhouse gases to levels well below those prevailing today. Since carbon dioxide results from the burning of all fossil fuels-coal, oil, natural gas, wood, peat, you name it-the only effective way to cut emissions is to limit the use of energy, either through a high carbon tax (on gasoline and electricity, for example) or by government fiat (the sort of blackouts we see in California). President Clinton's Department of Energy estimated the cost of enforcing such limits on the United States alone at $300 billion to $400 billion-that is, 3 to 4 percent of GDP-a year.

It was hardly surprising, therefore, that the Senate in July 1997 pledged, 95-0, not to ratify any climate-change treaty that exempted developing nations and caused "serious harm" to the U.S. economy. The Kyoto treaty did both, but four months later Al Gore signed it anyway. In the ensuing three years, no developed nation (unless you count Romania) ratified it-though the Europeans and Japanese heaped scorn on Americans for resisting. This March, President George W. Bush took the obvious-and courageous-step of rejecting Kyoto. It was, he said, "fatally flawed in fundamental ways." Bush did two other things: He asked the National Academy of Sciences quickly to review the state of knowledge about climate change, and he ordered a cabinet-level working group at the White House to conduct an unprecedented seminar on global warming, listening to scientists and economists explain what was known and unknown. We both participated in that process.

On June 11, five days after the Academy issued its report, the president gave a clear, smart, and forceful presentation on climate change in the Rose Garden. He quickly dismissed Kyoto but said that climate change was a serious matter. He reviewed the science and noted that the United States had spent $18 billion on climate research since 1990-"more than Japan and all 15 nations of the EU combined"-but that this wasn't enough. There are too many gaps in our knowledge. First, he said, we need to know the nature of the problem. Then, if it is serious and conducive to mitigation, we will try to fix it. But sound science comes first.

He was, of course, exactly right, but the press-more biased on environmental issues than on most others-chose to concentrate on the conflicts he would have with Europeans on his imminent trip there and to ignore such remarks as: "Our useful efforts to reduce sulfur emissions may have actually increased warming, because sulfate particles reflect sunlight, bouncing it back into space." These are nuanced issues, and, unlike most reporters, the president showed a command of the subject.

It was predictable that when the Academy's report appeared, it would be distorted by the media. The New York Times, the worst of the cheerleaders for calamitology, said in a lead story, "A panel of top American scientists declared today that global warming was a real problem and was getting worse, a conclusion that may lead President Bush to change his stand on the issue as he heads next week to Europe." This sort of wishful thinking was a theme of the coverage. Said an Arizona Republic headline: "Global Warming Confirmed; Finding by Panel Means Pressure for White House." Michelle Mitchell of CNN reported that the Academy study was "a unanimous decision that global warming is real, is getting worse, and is due to man. There is no wiggle room."

No wiggle room! In fact, no sensible person who reads the report (and it is only 28 pages long; read it at can come to any other conclusion than that there are enormous uncertainties about whether the earth will heat up in a dangerous way in the next century, and whether human-induced greenhouse gases are a significant culprit. Those are the essential questions, and the Academy's panel of 12 distinguished scientists said there are no answers. In fact, in the brief report, the words "uncertain" and "uncertainty" appear 43 times.

But journalists either did not read the report, or they willfully ignored it. It's true that an accompanying press release and brief summary may have misled reporters, but there's no excuse for missing such conclusions as this one on the very first page of the study:

Because there is considerable uncertainty in current understanding of how the climate system varies naturally and reacts to emissions of greenhouse gases and aerosols, current estimates of the magnitude of future warming should be regarded as tentative and subject to future adjustments (either upward or downward). The big news according to the media was that the earth has gotten warmer. Confirmed! But this is a non-event. No scientist doubts that over the past 100 years, the temperature observed near the surface and averaged over the earth has increased by about 1 degree Fahrenheit. But there are three important qualifications of that fact:

(1) There was a strong surface warming between the 1890s and the 1940s, followed by a pronounced cooling (and warnings of a catastrophic ice age by some of the same calamitologists who now claim disastrous warming) from the 1940s to the 1970s, then rising temperatures again from the 1970s to today. What's important is that carbon dioxide emissions were insignificant in the early 20th century, yet substantial warming occurred anyway. That warming must owe something to natural causes of climate change.

(2) The warming of 1 degree Fahrenheit seems to have had beneficial effects. It increased growing seasons, for instance, and reduced winter heating needs. Certainly, if judged by improvements in human and environmental health, wealth, and welfare in the 20th century, it has had no adverse effects.

(3) The recent warming has been observed only on the surface of the earth, using thermometer measurements that have major uncertainties-for example, the local heating produced by growing, mechanized cities. More sophisticated temperature records-taken from the surface to a few miles up into the lower atmosphere using NASA satellites-show no warming over the past 22 years, the period for which the satellites have been yielding measurements.

That last point is worth expanding, because it lies at the heart of the debate on the magnitude of human-made warming. According to the story that calamitologists tell, the lower layer of air must warm, in concert with the earth's surface, when the air's carbon dioxide content increases. The projections made by computer simulations of the climate insist that the increase in the air's concentration of carbon dioxide should have caused a warming in the lower air of about 1 degree Fahrenheit. But no such trend can be seen in the record.

Why not? Explanations of the discrepancy just don't wash. Maybe the satellite readings are in error? But they are vetted daily by independent measurements from balloon-borne instruments. The correlation between the two data sets is nearly perfect, establishing the global satellite temperature record as one of the most precise and important readings that we have for testing the question of human-made global warming.

Perhaps soot lofted into the air from human industry masks the expected warming by carbon dioxide? Particles of soot aloft, according to this idea, reflect sunlight away from much of the earth, producing a cooling trend that offsets the warming effects of CO2-hence the lack of evidence in the satellite record, though humans are heating the planet.

That, anyway, is the theory. Unfortunately for the calamitologists, it can readily be tested. Simply compare the difference in observed temperature trends between two halves of the earth. Most of the industrial soot stays in the Northern Hemisphere. There, the shading by the soot aerosols ought to mask the warming by CO2, and show little or no warming trend. On the other hand, the Southern Hemisphere, relatively free of the soot, should show largely unmasked warming.

But in fact, the Southern Hemisphere shows a distinct cooling trend, forcing us to modify or abandon the aerosol shading theory. Of the human-made aerosol effect, the Academy report states that its impact "is a large source of uncertainty about future climate change" and that "the monitoring of aerosol properties has not been adequate to yield accurate knowledge of the aerosol climate influence."

Aerosols may also influence clouds, the second of the two large factors in the natural greenhouse effect. Of the possible impact of aerosols on clouds, the report concludes, its "great uncertainty . . . presents a severe handicap both for the interpretation of past climate change and for future assessments of climate changes." The wiggle room seems to be increasing.

And clouds are closely related to the most important natural greenhouse agent, water vapor. The computer simulations that produce alarming levels of warming over the next century all assume that water vapor will amplify the small bit of warming expected from an increase of carbon dioxide concentration in the air.

That assumption, however, has not been verified by any actual measurement. The Academy report states, "The nature and magnitude of these hydrological feedbacks give rise to the largest source of uncertainty about climate sensitivity, and they are an area of continuing research."

Indeed, hydrological feedbacks might diminish or magnify warming trends. But all the computer models assume that water-vapor feedbacks produce a large gain in global warming. If that assumption is untrue, then every model exaggerates warming at the lowest levels of the atmosphere. Both clouds and water vapor-each more important in the greenhouse effect than CO2-are simply not understood by climatologists.

Richard Lindzen, the Alfred P. Sloan Professor of Meteorology at MIT and one of the scientists serving on the Academy panel, has worked out a stunning hypothesis with colleagues at NASA: Cirrus clouds may act as thermostats. As the earth warms, clouds adjust in their surface coverage, shedding more energy back to space. But all the computer models assume no change in cloud activity from warming.

In fact, Lindzen believes that clouds tend to reduce much of the warming expected from increased CO2. Just how big an effect do these clouds have as a thermostat, turning down the heat? The Lindzen group estimates that if doubling carbon dioxide would increase temperature as much as 7 degrees F, the cloud effect alone could hold that increase down to less than 2.5 degrees F.

Without computer models, there would be no evidence of global warming, no predictions of disaster, no Kyoto. So far, remember, the earth has increased its temperature by just one degree in a century. By simulating the climate on giant, ultra-fast computers, scholars try to find out how it will react to each new stimulus-like a doubling of CO2. An ideal computer model, however, would have to track five million parameters over the surface of the earth and through the atmosphere, and incorporate all relevant interactions among land, sea, air, ice, and vegetation. According to one researcher, such a model would demand ten million trillion degrees of freedom to solve, a computational impossibility even on the most advanced supercomputer. The Academy report puts it this way: "Climate models are imperfect. Their simulation skill is limited by uncertainties in their formulation, the limited size of their calculations, and the difficulty in interpreting their answers that exhibit almost as much complexity as in nature."

In addition, the forecasts are so new that they haven't been tested. An economic model might have predicted in 1990 that GDP would grow by 4 percent in 2000. Economists could see if it was right and, if not, change it. But climate models can only be backtested-that is, applied to the past, and even then they come up short. Lindzen noted in Senate testimony on May 2 the "widespread agreement" among climate scientists "that large computer models are unable to even simulate major features of past climate." That means we can have no confidence in the models to forecast future climate.

Perhaps more important, the National Academy of Sciences' report highlights the difficulty in understanding natural climate changes. And if we can't understand those, then we can't figure out the human effect. One major natural component in changing the climate is-not surprisingly-the sun. New findings, based on satellite measurements, suggest that heat emanating from the sun to the earth changes significantly on time scales of decades to centuries. NASA satellites have uncovered the fact that the sun's changing magnetism over the course of its sunspot cycle is accompanied by a change in total energy output.

This may be the simple explanation for temperature change on earth: The amount of energy reaching us increases or decreases as the sun brightens and fades. And the change in solar magnetism, or total energy output, is highly correlated with changes in the temperature of the Northern Hemisphere going back 240 years (records of the entire earth over this period are not accurate enough to study). The sun is today as magnetically active as it has been in 400 years of direct telescope observations. In other words, the mystery of global warming may have a simple solution-it's the sun that's heating the earth, with its heat rising and falling in fairly regular cycles. If so, there's nothing humans can do about it.

The temperature records of the Medieval Warm Period and the Little Ice Age are not precise, but the larger trends of those centuries are clear. The pattern of widespread warming followed by strong cooling also tracks the measured changes in the sun's magnetism. That information is captured in tree ring measurements of radiocarbon, whose formation in the upper air by cosmic rays-fast moving particles from the galaxy-is modulated by the swings in the sun's magnetism. That record reveals that the sun's activity waned at the onset of the Little Ice Age, then recovered to its current energetic state.

Recent research indicates other influences of the sun on the climate. Certain wavelengths of the sun's energy output, like the ultraviolet rays so important to the chemistry of the upper reaches of the earth's atmosphere, vary tremendously over a decade or longer, and seem to alter wind and weather patterns, and clouds.

Most recently, a research team at the Harvard-Smithsonian Center for Astrophysics has linked the temperatures, measured by satellites, of the low layer of air to changes in the varying flow of fast-moving electrons pelting the earth over the sunspot cycle. Whatever the explanation for the sun's influence, the fact is that the sun's imprint is very strong in the climate record, and the computer simulations fail to capture it.

The truth about climate change is that we don't know much about it. The bad news is that a major global warming could do a lot of harm. The good news is that we have ample time to find out if it's on the way, and that so far the scientific evidence does not support catastrophic warming, from any cause, human or otherwise. Taking the exaggerated forecasts of the deficient computer models at face value, we could still delay making initial cuts in CO2 emissions for as long as three decades and pay just a tiny penalty 100 years from now-less than half a degree Fahrenheit, a trivial amount in the wash of natural climate fluctuations. That gives us a wide opening for improving climate science so that it can define the magnitude of the human effect, develop cost-effective CO2 mitigation technology, and consider adaptation strategies-if climate change turns out to be a real risk.

Global warming is not a here-and-now problem. If the computers are right, the dire effects will unfold slowly over the century. But signs now indicate that the models vastly overstate the problem. We'll see. Only serious research on a large scale-an unbiased U.S. effort, funded by both industry and government-can answer the essential questions about climate change. Kyoto was based on unsound science. If it's dead-and that is by no means certain, given the factional struggles within the Bush administration-we can concentrate our efforts on sound science, and use it as a foundation for sound public policy.

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