Acclimatizing: how to think sensibly, or ridiculously, about global warming.

THE crusade to fight global warming with tough reductions in greenhouse-gas emissions has entered its war-room phase. Already we are seeing the fruits of a multi-million dollar PR campaign: lavish cover stories in Time magazine ("Be Worried, Be Very Worried"), Vanity Fair, and Wired; multiple global-warming scare specials on PBS, HBO, and the network news; and, finally, the imminent release of Al Gore's documentary An Inconvenient Truth. Soon the Ad Council will begin airing TV spots pulling on the usual heartstrings: We have to stop global warming for the children! One of these ads--featuring a montage of kids counting down "tick, tick, tick"--is reminiscent of the infamous 1964 anti-Goldwater ad.

Unfortunately, the green warriors substitute propaganda for persuasion, insist that there is no debate about the science of climate change, and demonize any scientist who dares dissent from their views. They advocate putting the U.S. and the world on an energy starvation diet, to the exclusion of a wider and more moderate range of precautions that might be taken against global warming.

Underlying this effort is a sense of panic over two things: the collapse of the Kyoto Protocol, and frequent polls showing that Americans aren't buying into global-warming alarmism. The latest Gallup poll on environmental issues found that only 36 percent of Americans say they "worry a great deal about global warming"--a number that has hardly budged in years. Global warming, Gallup's environmental-opinion analyst Riley Dunlap wrote, puts people to sleep. Even among those who tell pollsters that the environment is their main public-policy concern (who are usually less than 5 percent of all Americans), global warming ranks lower than air and water quality, toxic waste, and land conservation.

There is no conspiracy behind the global-warming-awareness campaign; in fact, the environment lobby is quite open about what it's up to. The Yale School of Forestry and Environmental Studies recently published a plan to elevate climate change to the top tier of the political agenda. This report, Americans and Climate Change, grew out of a summit meeting of environmental leaders held last year in--naturally--Aspen. It lists 39 recommendations for raising the percentage of the public that is alarmed by global warming from the anemic mid-30s to over 50 percent. Tactics include everything from manipulating public-school curricula to reaching out to NASCAR's fan base to seizing events like Hurricane Katrina as "teachable moments."

The Yale report also does us the favor of making its authors' desire to politicize climate change explicit. One faction of environmentalists openly argues that "the only way to proceed is to exercise raw political power, wake up the public about the urgent nature of the issue, create a major public demand for action comparable to that which stimulated major environmental legislation in the 1970s, pursue outright victory at the polls." In other words, we need to boot out those evil Republicans.

GAME OVER, THEY SAY

This campaign intimidates the public and would-be dissenters with its unrelenting line that the science of global warming is settled, full stop. (Time swallowed it whole: "The debate is over. Global warming is upon us--with a vengeance. From floods to fires, droughts to storms, the climate is crashing.") The "consensus" that human activities are playing a role in the earth's so-far mild warming trend is misrepresented as agreement that we are headed toward catastrophic results that can be prevented only by immediate and drastic action.

In fact, many scientists don't believe the catastrophe scenarios. But those who dissent from the politicization of climate science face withering ad hominem attacks. For example, the National Environmental Trust and Vanity Fair attacked Frederick Seitz, the 94-year-old former president of the National Academy of Sciences, for supposedly taking money from R. J. Reynolds while he was president of Rockefeller University to deny the health effects of smoking. In fact, the money went into a medical-research project unrelated to tobacco that led to a Nobel Prize in medicine. The climate-action caucus clearly feels no shame about employing smear tactics. One might even go so far as to accuse it of scientific McCarthyism.

But try as it might, this caucus cannot change two facts that have been evident since climate change first came to the fore in the late 1980s. First, even though the leading scientific journals are thoroughly imbued with environmental correctness and reject out of hand many articles that don't conform to the party line, a study that confounds the conventional wisdom is published almost every week. Sometimes these studies even find their way into Science and Nature. Most recently, the April 20 issue of Nature carried a study that casts serious doubt on the high-temperature forecasts of computer climate models. And last fall, Science published a study finding that the Greenland ice sheet, whose perimeter melting is presented as a sign of imminent sea-level rise (never mind that the Vikings observed similar melting 1,000 years ago), is gaining ice mass in the interior. (The oddest aspect of the Greenland story is that average temperatures in southern Greenland appear to have fallen during the 20th century; ice-mass changes probably have more to do with regular variation in Atlantic ocean currents--a natural phenomenon known as Atlantic Multidecadal Oscillation.) The media tend to ignore such research while giving disproportionate coverage to the latest news about melting glaciers or expiring frogs.

Climate alarm is likely to get a fresh infusion of "authoritative" science next year when the Intergovernmental Panel on Climate Change (IPCC) issues its Fourth Assessment Report (AR4). Early indications are that AR4 will remove its upper-bound estimate of potential warming at the end of this century (currently 5.8 degrees Celsius), assuring a fresh round of media headlines that the situation is worse than we thought. Yet the computer climate models remain plagued with weaknesses and biases--from the doubtful emissions forecasts that go into the front end, to assumptions about the linearity of the relationship between greenhouse gases and temperature that affect the results. As MIT climatologist Richard Lindzen argues, the computer models overestimate the sensitivity of climate to greenhouse gases and don't adequately account for "negative forcings" (the technical term for natural processes that mitigate potential temperature increases). It is likely, in Lindzen's judgment, that we have already reached the threshold of diminishing "positive forcings" (that is, increases in temperature) from additional greenhouse-gas emissions.

Most of the computer models predict temperature increases of two to three degrees Celsius by the year 2100, which, while not an "end of civilization as we know it" catastrophe, could cause significant problems for the planet. Even discounting for the biases in the models, these predictions still raise questions about what precautions are appropriate to take against a low-probability event with potentially serious consequences. This leads to the second difficulty for the climate-change crusade: There are alternatives to its insistence that the only appropriate policy response is steep and immediate emissions reductions (on the order of 60 percent). Kyoto's 8 percent reduction target is modest by comparison, but no nation is honestly meeting it. (Britain met its 2000 target as an unintended consequence of Margaret Thatcher's decision 20 years ago to smash the coal miners' union and move the nation to natural gas. But even with this wind in its sails, Britain is seeing its greenhouse-gas emissions start to rise again.) The energy technologies to achieve a 60 percent reduction in emissions while meeting the world's energy needs simply do not exist.

Environmentalists were against fossil fuels long before climate change rose to prominence, and this monomania is evident in their continued opposition to nuclear power, the only technology that can generate large amounts of energy without emitting greenhouse gases. (In a recent C-SPAN appearance with me, the legislative director of the League of Conservation Voters said that nuclear power had no role to play in mitigating climate change.) Instead, environmentalists advocate a supposedly market-friendly "cap and trade" program. Such a program would impose downwardly ratcheting emissions caps; but instead of creating thousands of detailed Clean Air Act-style regulations, it would grant "emissions permits" to companies, which would be able to trade these permits among each other. If one company's emissions were lower than the allowed amount, it could trade or sell its "leftover" allotment to a second company, which could add that amount to its own emissions allotment. The idea of such trading is to let the market guide emissions reductions to the companies able to undertake them most efficiently.

"Cap and trade" is thought to have been a great success in reducing sulfur-dioxide emissions at low cost. But there is a world of difference between sulfur dioxide and greenhouse gases. For a variety of reasons, curbs on sulfur dioxide did not impose any constraint on net energy production, whereas a greenhouse-gas-emissions cap ultimately would constrain energy production.

A COMMONSENSE AND WORKABLE PLAN

A sensible climate policy would emphasize building resilience into our capacity to adapt to climate changes--whether cooling or warming; whether wholly natural, wholly man-made, or somewhere in between. A resilience policy, instead of focusing solely on emissions controls, would have four parts.

First, the transition to a post-carbon world decades from now will come about more quickly and efficiently by keeping energy markets open and unregulated than by subsidizing particular energy technologies or artificially making energy more expensive for producers and consumers. Efforts to subsidize energy paths will inevitably fall prey to interest-group lobbying (as witness the domestic ethanol lobby's success in winning tariffs on foreign ethanol), and will likely delay the development of promising technologies.

Second, we should implement practical carbon-sequestration measures: the capturing and storing of carbon in any number of places, whether underground, deep in the ocean, or in biomass (think more trees). There is much sequestration research under way, but many environmentalists oppose it because it would let us off the hook for our original sin of energy consumption.

Third, we should consider strategies of adaptation to a changing climate. A rise in the sea level need not be the end of the world, as the Dutch have taught us. Developing countries with vulnerable coastlines will be better able to adapt if their economic growth is not constrained by severe energy limits. And here at home, the federal government ought to stop subsidizing flood insurance and coastal development anyway; potential climate change is another reason to eschew such policies.

Finally, we should consider climate modification. If humanity is powerful enough to disrupt the climate negatively, we might also be able to change it for the better. On a theoretical level, doing so is relatively simple: We need to reduce the earth's absorption of solar radiation. A few scientists have suggested we could accomplish this by using orbiting mirrors to rebalance the amounts of solar radiation different parts of the earth receive. Right now this idea sounds as fanciful as Ronald Reagan's Strategic Defense Initiative seemed in 1983, but look what that led to. New York University physicist Martin Hoffert points out that the interval between the Wright brothers' first flight at Kitty Hawk and Neil Armstrong's first step on the moon was a mere 66 years. It is entirely reasonable to expect vast changes in our technical capacity before the century is out.

In the end, a relentless campaign to extend political control over the world's energy use is likely to fail, in part because, even if severe climate change is in our future, most people intuitively recognize that rhetoric about "the end of civilization as we know it" is inconsistent with human experience. Our distant ancestors survived an ice age with little more than animal skins, crude tools, and open fire pits. For all the talk of science and progress, the global-warming alarmists betray an astonishing lack of confidence in human creativity and resiliency. It's almost as if the scientific community had abandoned the idea of evolution.

Mr. Hayward is a fellow of the American Enterprise Institute, and the author of the annual Index of Leading Environmental Indicators.