GLOBAL WARMING
http://www.hillsdale.edu/news/imprimis.asp
S. Fred Singer [Not Peter Singer]
S. Fred Singer is professor emeritus of environmental sciences at the University of Virginia, a distinguished research professor at George Mason University, and president of the Science and Environmental Policy Project. He performed his undergraduate studies at Ohio State University and earned his Ph.D. in Physics from Princeton University. He was the founding dean of the School of Environmental and Planetary Sciences at the University of Miami, the founding director of the U.S. National Weather Satellite Service, and served for five years as vice chairman of the U.S. National Advisory Committee on Oceans and Atmosphere. Dr. Singer has written or edited over a dozen books and mono-graphs, including, most recently, Unstoppable Global Warming: Every 1,500 Years.
The following is adapted from a lecture delivered on the Hillsdale College campus on June 30, 2007, during a seminar entitled “Economics and the Environment,” sponsored by the Charles R. and Kathleen K. Hoogland Center for Teacher Excellence. [http://www.hillsdale.edu/news/imprimis.asp]
Global Warming: Man-Made or Natural?
IN THE PAST few years there has been increasing concern about global climate change on the part of the media, politicians, and the public. It has been stimulated by the idea that human activities may influence global climate adversely and that therefore corrective action is required on the part of governments. Recent evidence suggests that this concern is misplaced.
Human activities are not influencing the global climate in a perceptible way. Climate will continue to change, as it always has in the past, warming and cooling on different time scales and for different reasons, regardless of human action. I would also argue that—should it occur—a modest warming would be on the whole beneficial.
This is not to say that we don’t face a serious problem. But the problem is political. Because of the mistaken idea that governments can and must do something about climate, pressures are building that have the potential of distorting energy policies in a way that will severely damage national economies, decrease standards of living, and increase poverty.
This misdirection of resources will adversely affect human health and welfare in industrialized nations, and even more in developing nations. Thus it could well lead to increased social tensions within nations and conflict between them.
If not for this economic and political damage, one might consider the present concern about climate change nothing more than just another environmentalist fad, like the Alar apple scare or the global cooling fears of the 1970s. Given that so much is at stake, however, it is essential that people better understand the issue.
Man-Made Warming?
The most fundamental question is scientific: Is the observed warming of the past 30 years due to natural causes or are human activities a main or even a contributing factor?
At first glance, it is quite plausible that humans could be responsible for warming the climate. After all, the burning of fossil fuels to generate energy releases large quantities of carbon dioxide into the atmosphere. The CO2 level has been increasing steadily since the beginning of the industrial revolution and is now 35 percent higher than it was 200 years ago. Also, we know from direct measurements that CO2 is a “greenhouse gas” which strongly absorbs infrared (heat) radiation. So the idea that burning fossil fuels causes an enhanced “greenhouse effect” needs to be taken seriously.
But in seeking to understand recent warming, we also have to consider the natural factors that have regularly warmed the climate prior to the industrial revolution and, indeed, prior to any human presence on the earth. After all, the geological record shows a persistent 1,500-year cycle of warming and cooling extending back at least one million years.
In identifying the burning of fossil fuels as the chief cause of warming today, many politicians and environmental activists simply appeal to a so-called “scientific consensus.”
There are two things wrong with this.
First, there is no such consensus: An increasing number of climate scientists are raising serious questions about the political rush to judgment on this issue.
For example, the widely touted “consensus” of 2,500 scientists on the United Nations Intergovernmental Panel on Climate Change (IPCC) is an illusion: Most of the panelists have no scientific qualifications, and many of the others object to some part of the IPCC’s report.
The Associated Press reported recently that only 52 climate scientists contributed to the report’s “Summary for Policymakers.”
Likewise, only about a dozen members of the governing board voted on the “consensus statement” on climate change by the American Meteorological Society (AMS).
Rank and file AMS scientists never had a say, which is why so many of them are now openly rebelling. Estimates of skepticism within the AMS regarding man-made global warming are well over 50 percent.
The second reason not to rely on a “scientific consensus” in these matters is that this is not how science works. After all, scientific advances customarily come from a minority of scientists who challenge the majority view—or even just a single person (think of Galileo or Einstein). Science proceeds by the scientific method and draws conclusions based on evidence, not on a show of hands.
But aren’t glaciers melting? Isn’t sea ice shrinking? Yes, but that’s not proof for human-caused warming. Any kind of warming, whether natural or human-caused, will melt ice. To assert that melting glaciers prove human causation is just bad logic.
What about the fact that carbon dioxide levels are increasing at the same time temperatures are rising? That’s an interesting correlation; but as every scientist knows, correlation is not causation. During much of the last century the climate was cooling while CO2 levels were rising. And we should note that the climate has not warmed in the past eight years, even though greenhouse gas levels have increased rapidly.
What about the fact—as cited by, among others, those who produced the IPCC report—that every major greenhouse computer model (there are two dozen or so) shows a large temperature increase due to human burning of fossil fuels? Fortunately, there is a scientific way of testing these models to see whether current warming is due to a man-made greenhouse effect.
It involves comparing the actual or observed pattern of warming with the warming pattern predicted by or calculated from the models. Essentially, we try to see if the “fingerprints” match—“fingerprints” meaning the rates of warming at different latitudes and altitudes.
For instance, theoretically, greenhouse warming in the tropics should register at increasingly high rates as one moves from the surface of the earth up into the atmosphere, peaking at about six miles abov
e the earth’s surface.
At that point, the level should be greater than at the surface by about a factor of three and quite pronounced, according to all the computer models. In reality, however, there is no increase at all. In fact, the data from balloon-borne radiosondes show the very opposite: a slight decrease in warming over the equator.
The fact that the observed and predicted patterns of warming don’t match indicates that the man-made greenhouse contribution to current temperature change is insignificant.
This fact emerges from data and graphs collected in the Climate Change Science Program Report 1.1, published by the federal government in April 2006 (see www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm). It is remarkable and puzzling that few have noticed this disparity between observed and predicted patterns of warming and drawn the obvious scientific conclusion.
What explains why greenhouse computer models predict temperature trends that are so much larger than those observed? The answer lies in the proper evaluation of feedback within the models.
Remember that in addition to carbon dioxide, the real atmosphere contains water vapor, the most powerful greenhouse gas. Every one of the climate models calculates a significant positive feedback from water vapor—i.e., a feedback that amplifies the warming effect of the CO2 increase by an average factor of two or three. But it is quite possible that the water vapor feedback is negative rather than positive and thereby reduces the effect of increased CO2.
There are several ways this might occur.
For example, when increased CO2 produces a warming of the ocean, a higher rate of evaporation might lead to more humidity and cloudiness (provided the atmosphere contains a sufficient number of cloud condensation nuclei). These low clouds reflect incoming solar radiation back into space and thereby cool the earth. Climate researchers have discovered other possible feedbacks and are busy evaluating which ones enhance and which diminish the effect of increasing CO2.
Natural Causes of Warming
A quite different question, but scientifically interesting, has to do with the natural factors influencing climate. This is a big topic about which much has been written. Natural factors include continental drift and mountain-building, changes in the Earth’s orbit, volcanic eruptions, and solar variability. Different factors operate on different time scales. But on a time scale important for human experience—a scale of decades, let’s say—solar variability may be the most important.
Solar influence can manifest itself in different ways: fluctuations of solar irradiance (total energy), which has been measured in satellites and related to the sunspot cycle; variability of the ultraviolet portion of the solar spectrum, which in turn affects the amount of ozone in the stratosphere; and variations in the solar wind that modulate the intensity of cosmic rays (which, upon impact into the earth’s atmosphere, produce cloud condensation nuclei, affecting cloudiness and thus climate).
Scientists have been able to trace the impact of the sun on past climate using proxy data (since thermometers are relatively modern). A conventional proxy for temperature is the ratio of the heavy isotope of oxygen, Oxygen-18, to the most common form, Oxygen-16.
A paper published in Nature in 2001 describes the Oxygen-18 data (reflecting temperature) from a stalagmite in a cave in Oman, covering a period of over 3,000 years. It also shows corresponding Carbon-14 data, which are directly related to the intensity of cosmic rays striking the earth’s atmosphere.
One sees there a remarkably detailed correlation, almost on a year-by-year basis. While such research cannot establish the detailed mechanism of climate change, the causal connection is quite clear: Since the stalagmite temperature cannot affect the sun, it is the sun that affects climate.
Policy Consequences
If this line of reasoning is correct, human-caused increases in the CO2 level are quite insignificant to climate change. Natural causes of climate change, for their part, cannot be controlled by man. They are unstoppable. Several policy consequences would follow from this simple fact:
> Regulation of CO2 emissions is pointless and even counterproductive, in that no matter what kind of mitigation scheme is used, such regulation is hugely expensive.
> The development of non-fossil fuel energy sources, like ethanol and hydrogen, might be counterproductive, given that they have to be manufactured, often with the investment of great amounts of ordinary energy. Nor do they offer much reduction in oil imports.
> Wind power and solar power become less attractive, being uneconomic and requiring huge subsidies.
> Substituting natural gas for coal in electricity generation makes less sense for the same reasons.
None of this is intended to argue against energy conservation. On the contrary, conserving energy reduces waste, saves money, and lowers energy prices—irrespective of what one may believe about global warming.
Science vs. Hysteria
You will note that this has been a rational discussion. We asked the important question of whether there is appreciable man-made warming today. We presented evidence that indicates there is not, thereby suggesting that attempts by governments to control greenhouse-gas emissions are pointless and unwise.
Nevertheless, we have state governors calling for CO2 emissions limits on cars; we have city mayors calling for mandatory CO2 controls; we have the Supreme Court declaring CO2 a pollutant that may have to be regulated; we have every industrialized nation (with the exception of the U.S. and Australia) signed on to the Kyoto Protocol; and we have ongoing international demands for even more stringent controls when Kyoto expires in 2012. What’s going on here?
To begin, perhaps even some of the advocates of these anti-warming policies are not so serious about them, as seen in a feature of the Kyoto Protocol called the Clean Development Mechanism, which allows a CO2 emitter—i.e., an energy user—to support a fanciful CO2 reduction scheme in developing nations in exchange for the right to keep on emitting CO2 unabated.
“Emission trading” among those countries that have ratified Kyoto allows for the sale of certificates of unused emission quotas. In many cases, the initial quota was simply given away by governments to power companies and other entities, which in turn collect a windfall fee from consumers. All of this has become a huge financial racket that could someday make the UN’s “Oil for Food” scandal in Iraq seem minor by comparison. Even more fraudulent, these schemes do not reduce total CO2 emissions—not even in theory.
It is also worth noting that tens of thousands of interested persons benefit directly from the global warming scare—at the expense of the ordinary consumer. Environmental organizations globally, such as Greenpeace, the Sierra Club, and the Environmental Defense Fund, have raked in billions of dollars. Multi-billion-dollar government subsidies for useless mitigation schemes are large and growing.
Emi
ssion trading programs will soon reach the $100 billion a year level, with large fees paid to brokers and those who operate the scams. In other words, many people have discovered they can benefit from climate scares and have formed an entrenched interest. Of course, there are also many sincere believers in an impending global warming catastrophe, spurred on in their fears by the growing number of one-sided books, movies, and media coverage.
The irony is that a slightly warmer climate with more carbon dioxide is in many ways beneficial rather than damaging. Economic studies have demonstrated that a modest warming and higher CO2 levels will increase GNP and raise standards of living, primarily by improving agriculture and forestry. It’s a well-known fact that CO2 is plant food and essential to the growth of crops and trees—and ultimately to the well-being of animals and humans.
You wouldn’t know it from Al Gore’s An Inconvenient Truth, but there are many upsides to global warming: Northern homes could save on heating fuel. Canadian farmers could harvest bumper crops. Greenland may become awash in cod and oil riches. Shippers could count on an Arctic shortcut between the Atlantic and Pacific. Forests may expand.
Mongolia could become an economic superpower. This is all speculative, even a little facetious. But still, might there be a silver lining for the frigid regions of Canada and Russia? “It’s not that there won’t be bad things happening in those countries,” economics professor Robert O. Mendelsohn of the Yale School of Forestry & Environmental Studies says.
“But the idea is that they will get such large gains, especially in agriculture, that they will be bigger than the losses.” Mendelsohn has looked at how gross domestic product around the world would be affected under different warming scenarios through 2100. Canada and Russia tend to come out as clear gainers, as does much of northern Europe and Mongolia, largely because of projected increases in agricultural production.
To repeat a point made at the beginning: Climate has been changing cyclically for at least a million years and has shown huge variations over geological time. Human beings have adapted well, and will continue to do so.
* * *
The nations of the world face many difficult problems. Many have societal problems like poverty, disease, lack of sanitation, and shortage of clean water. There are grave security problems arising from global terrorism and the proliferation of nuclear weapons.
Any of these problems are vastly more important than the imaginary problem of man-made global warming. It is a great shame that so many of our resources are being diverted from real problems to this non-problem. Perhaps in ten or 20 years this will become apparent to everyone, particularly if the climate should stop warming (as it has for eight years now) or even begin to cool.
We can only trust that reason will prevail in the face of an onslaught of propaganda like Al Gore’s movie and despite the incessant misinformation generated by the media. Today, the imposed costs are still modest, and mostly hidden in taxes and in charges for electricity and motor fuels. If the scaremongers have their way, these costs will become enormous. But I believe that sound science and good sense will prevail in the face of irrational and scientifically baseless climate fears.
[http://www.hillsdale.edu/news/imprimis.asp, August 2007, S. Fred Singer, Professor Emeritus, Environmental Sciences, University of Virginia]
The Politics of Global Warming
http://www.firstthings.com/article.php3?id_article=6000
With the virtual apotheosis of Al Gore, talk of global warming has become pervasive—and pervasively one-sided. Churches of all varieties have signed on as a moral cause. Corporations, including former doubters, have adopted anti-warming language, either from new conviction or convenient public image. Politicians, with few exceptions, dare not openly deny that there is a problem, though their responses may vary.
Through it all, one would never know there are dissenters of distinguished credentials in the scientific community. Even where their existence is admitted, they are thoroughly marginalized, accused of being in the pay of the oil companies (Gore slyly and meanly implies this in his movie, An Inconvenient Truth), or dismissed as over-the-hill retirees out of touch and perhaps a bit senile. Their articles are denied publication in Science and Nature, those two so-called flagship science journals of high reputation despite some embarrassing lapses.
When dissenters do speak and publish, the majority who embrace the prevailing theory that humans are causing global warming try to silence them on the grounds that, because they are in error, they must not be allowed to be heard. Newspapers who seek balance in their reporting are told that they are doing a disservice to the public, to truth, and to the survival of the human race.
The Weather Channel, a full-bore promoter of global-warming alarm (which feeds its appetite for newsworthy disaster), has, through its chief climate expert Heidi Cullen, even said that weather reporters who don’t accept the reigning thesis should be decertified by the American Meteorological Society—in other words, believe our way or lose your job. When British television producer Martin Durkin made a counter-movie to Gore’s, the head of the Royal Society declared that he should not be allowed to show it.
The result is that anyone who finds the dissenters persuasive—including me—is suspected of being a right-wing extremist, making politics determine science. In vain do we point out that dissenters from established scientific consensus have often been dramatically vindicated. Undeterred, some of our critics have even compared us to Holocaust deniers or urged that dissenters be tried as war criminals. Or maybe burned at the stake for heresy—for our religious critics do think of us as heretics and sinners.
This dismal state of affairs is made possible by an astonishing historical amnesia. It is indisputable that climate swings are a regular feature of our planet’s life. Short-term changes lie within our personal memories: The current warming trend dates from only about 1975. Before that, a pronounced cooling period starting about 1940 led the scientific consensus of the 1970s to proclaim global cooling and perhaps the first signs of an ice age.
Note that these swings do not correspond to the amount of CO2 released into the atmosphere; 60 percent of global warming since 1850 occurred before 1940, while 80 percent of CO2 was emitted after that date—and temperatures fell from 1940 until the turnaround in the late 1970s.
Going further back, we find the “little ice age” of the sixteenth and seventeenth centuries, when the Hudson and the Thames froze, crops failed, and disease was rampant, so that millions died. Before that, we come upon the “medieval climate optimum,” when a prevailing warmth made life pleasant, grape vines grew in England, and the Vikings established settlements in Greenland and Newfoundland (which they called Vinland; the names are revealing)—settlements that lasted until the little ice age froze them out.
That period was, in turn, preceded by an unfavorable climate in the Dark Ages, and that by another warm stretch
in Roman times. Using proxy records (tree rings, ice-core samples, ocean-bottom sediment), geologists have determined that such climate swings stretch back into prehistory.
Fred Singer (who has impeccable credentials and experience as a climate scientist) and Dennis Avery have calculated that this swing-and-return pattern occurs roughly but regularly every 1,500 years. Obviously, the pattern has nothing to do with human activity. Nor does it correspond to the levels of CO2 in the atmosphere. If anything, climate change appears to precede, not follow, increases in CO2.
So what’s going on? There is a significant body of scientific opinion that finds the sun to be the principal climate driver. The sun’s output is variable and complex, more and less intense at different periods. A German team has shown an almost perfect correlation between air temperatures and solar cycles for the past 150 years.
A Danish team likewise has constructed a multi-era match of solar activity (measured by sunspots) to global temperatures. Nigel Weiss of Cambridge University, a mathematical astrophysicist and past president of the Royal Astronomical Society, also correlates sunspot activity with changes in the earth’s climate.
Because solar activity is cyclical, he expects that a downturn is coming and will usher in a cooling climate for earth in, maybe, three decades. Actually, global average temperature seems to have plateaued since 2000, though it is probably too soon to expect the downturn to have begun. Still, Richard Lindzen, a distinguished atmospheric physicist at MIT and a leading doubter that human activity is driving warming, thinks the odds are about 50 percent that the earth will be cooler in twenty years—due to natural cycles.
It may or may not be significant, but it is suggestive, that NASA’s instruments calculate that Mars, Jupiter, Pluto, and the Titan moon of Neptune are warming, suggesting a solar-system-wide phenomenon. To be sure, this is not hard evidence; other factors (axis tilt and wobble on Mars, for instance) may be a cause. Still, it may be a clue to what is happening here on our planet.
Some caveats are in order. Human activity may add something to the natural cycle, though how much is hard to tell. I have seen a paper that estimates the human contribution at 3 percent and another that gives it at 0.28 percent, for an almost undetectable effect on climate. The principal greenhouse gas, some 97 percent of the total, is water vapor, which leaves little for CO2 and other trace gasses. Scott McIntosh, of the Southwest Research Institute in Boulder, says that warming caused by CO2 compared to the effect of solar magnetic fields is like a flea’s contribution to the weight of an elephant.
We do know, however, that atmospheric emissions can affect climate—for example, the serious consequences of the ash cloud thrown up by volcanic eruptions; so perhaps there is something to the greenhouse-gas theory. People can also argue about the historical record and try to modify the data that shows natural climate cycles. There may be problems with the sun theory; climate is also affected by ocean currents, meteor impact, the tilt of the earth’s axis, cosmic rays, precipitation systems, and other factors. And so on. Those of us who are doubters will not complain when we in turn are doubted. Debate is healthy and must not be choked off.
Nevertheless, the large, rough historical record should be enough to awaken the critical instincts and make anyone take a long second look at the claims of the global-warming alarmists—and alarmists they certainly are, deliberately and unabashedly so.
They’ve claimed, for example, that the glaciers will melt in Greenland and Antarctica and raise the oceans so much that low-lying cities and countries will be submerged and the Gulf Stream will shut down and plunge Europe into an ice age.
As it happens, while there is edge-melting in Greenland and along the peninsula of Antarctica that stretches toward South America, snow is accumulating in the interior of Greenland and in most of Antarctica.
The warming peninsula there is just 2 percent of the continent; the other 98 percent is cooling. The Larson B ice shelf, which collapsed, was 1/246 the size of the West Antarctic ice shelf, which has been retreating slowly anyway for thousands of years. As for the Gulf Stream threat, oceanographers debunk it.
Even the Intergovernmental Panel on Climate Change (IPCC), the U.N. body that puts out huge periodic reports warning of climate disaster, has backed down from its earlier estimates of sea rise, from three feet for the next century to seventeen inches—and many scientists think even that is too high.
Speaking of glaciers, the alarmists point out that they are melting everywhere. Kilimanjaro will be bare in a few years, and the Alpine glaciers will be but pale shadows of themselves, and so on around the globe.
But Claude Allègre, a distinguished French climate scientist, has recanted his earlier support for the IPCC’s conclusions, and says of Kilimanjaro specifically that its snow cap is retreating from natural causes having to do with moisture from the Indian Ocean. Alpine glaciers, like most everywhere, grow and retreat often through their lives. In 2003, as the Schnidenjoch glacier in Switzerland was retreating, a 4,700-year-old archer’s quiver was exposed; that pass has been open to human travel many times since the last ice age.
On and on, the alarms go. Perhaps you’ve seen the claim that the Arctic sea ice is disappearing and that polar bears are threatened with extinction because they can’t hunt from ice floes any more. But Arctic sea ice, like the glaciers, grows and retreats in natural cycles. Gore’s computer simulation of the drowning polar bear may look sad, but, of course, it’s fake. Canadian wildlife biologists say most populations of the bears are actually increasing.
Or perhaps you’ve heard that storms on land and sea will increase in number and intensity, and we can expect more Katrinas. In fact, there has actually been a downward trend in the number of the bigger, detectable tornadoes since 1950; we detect more because better reporting picks up more small ones. New evidence shows that hurricane intensity does not correlate with ocean temperature.
Maybe you’ve read that tropical diseases such as malaria will spread into now-temperate zones, higher latitudes, and higher altitudes—Nairobi, for example. But Nairobi was built when malaria was already endemic there. It was repelled with better insecticide, especially, in Africa, DDT. The current resurgence of malaria comes not from global warming but from the ban on DDT spraying, growing resistance to drugs, and poverty.
You’ve also been told that failing to curb our greenhouse-gas emissions will cause irreparable economic damage to the poorer nations, as the Stern Report insisted. But the report was savaged by economists. William Nordhaus of Yale is among those who fault Stern for using a near-zero social-discount rate, which would charge current generations for problems not likely to occur for two or three centuries hence.
In fact, one can make the opposite case from Stern’s with greater plausibility: Economies would be wrecked by adoption of the Kyoto targets. Even a moderate stabilization of greenhouse-gas emissions would require something like a 60 to 80 percent reduction in fossil-fuel use, and standards of living would
drop through the floor.
Poor countries would have a nearly impossible time rising out of their poverty. Is it any wonder that China and India and other developing nations will have none of Kyoto-style proposals, and are loudly and clearly telling the developed nations to proceed without their participation? Naturally, they are much more interested in Bush’s proposal to bypass the useless Kyoto framework and substitute technological changes and voluntary goals for the binding targets championed by the Europeans.
One of the goofiest ways of raising consciousness about global warming has been the lectures we’ve received about purchasing carbon offsets. As it happens, the purchase of carbon offsets allows the buyer to continue his merry energy-guzzling ways, his sins having been forgiven for a cash payment. The process has the ring of a medieval indulgence sale, as many critics have gleefully noted. Gore buys carbon offsets so he can justify living in a mansion with huge electricity use. And he can certainly afford that, as his $100,000 lecture fees and his relations with Internet companies and environmental businesses have made him extraordinarily wealthy.
Everywhere you go, you hear the news that we have only a few years to save the planet before we reach the point of no return, the tipping point, irreversible catastrophic climate change, and the end of civilization. Hyperbolic statements like these are meant mainly to scare people into acting and accepting the enormous sums required for the proposed reduction program. Sir John Houghton, the first chair of the IPCC, wrote in a 1994 book, “Unless we announce disasters, no one will listen.”
A backlash against such exaggeration is growing, not least among scientists concerned for their own professional integrity. In any case, we need cooler heads to go with a warmer climate. Lindzen and Israeli astrophysicist Nir Shaviv calculate that a doubling of CO2 in the atmosphere by 2100 would cause a temperature rise of 1 degree Celsius, which is only a little more than the rise from the late nineteenth century to the present has been. A 50 percent rise would yield a 0.5-degree-C. increase.
There are, of course, good reasons for controlling many emissions and finding alternative sources to fossil fuels: pollution control, for instance, and freedom from economic fealty to some rather nasty oil-producing regimes. But stopping global warming is not one of them.
It almost seems as if the issue is not in science but in ideology and social psychology. Environmental alarmism is part of a systematic rejection of industrial civilization, of technology, consumerism, globalization, and what most of us think of as growth and progress, in favor of a return to local, simpler, largely agricultural societies—and, of course, fewer children, since humans are the ultimate pollution. Climate reversal has grown to become the latest focus of this way of thinking.
It is an issue that has acquired popular traction, even among people who do not share the radical goals of the larger movement, thanks to deliberate alarmism; and it is now firmly entrenched in our public discourse, especially in our politics. I suspect that it will stay there until the temperature starts to decline again, at which point, as in the 1970s, we’ll hear more about the inevitable return of an ice age.
Thomas Sieger Derr is professor emeritus of religion and ethics at Smith College and the author of Environmental Ethics and Christian Humanism. [http://www.firstthings.com/article.php3?id_article=6000, by Thomas Sieger Derr, Copyright (c) 2007 First Things (August/September 2007)]