Although we are getting better and better at it, forecasting the weather is still remarkably tricky. Far easier to predict the political climate, especially when it comes to the issue of global warming. To wit: In December, negotiators from around the world will meet in Kyoto to work out an international treaty to deal with what most (though not all) scientists believe is a 0.5-degree-centigrade increase in temperatures over the past century, and the promise of more to come.
All major participants, including the U.S. representatives, will argue that the only way to address global warming is to reduce significantly levels of carbon dioxide and other greenhouse gases that are plausibly (though not definitively) linked to the rise in temperatures. Although a group of small island nations will suggest a 20 percent reduction in greenhouse gases, members of the European Union will most likely carry the day with a plan to cut emissions of carbon dioxide, methane, and nitrous oxide by at least 15 percent over the next decade.
The Clinton administration may object to those specific targets, but it will enthusiastically support the consensus that the only way to counter global warming is by reducing emissions. Indeed, the president announced in August that "we owe it to our children" to sign a treaty reducing consumption of greenhouse gases, a position echoed by Interior Secretary Bruce Babbitt, who has called dissenters "un-American," and chief economic adviser Janet Yellen, who has called cost-benefit analyses of cutting greenhouse gases "futile."
Such thinking is perfectly in keeping with the universal environmentalist position, which is best understood as a starkly Puritan ethic: "Abstain, sinner!" "The only way to slow climate change is to use less fuel," asserts Bill McKibben in The End of Nature, a book that roundly condemns such luxuries as privately owned washing machines and oranges shipped to cold climates. And if a 15 percent reduction in greenhouse gases seems extreme, consider that many ecologists champion far more costly conservation measures as the only solution. Ross Gelbspan's The Heat Is On even urges a government takeover of the energy sector and a massive propaganda campaign. In the wake of the Kyoto conference, expect to see calls for a Greenhouse Czar as global warming is brought to broad, persistent public notice.
Such hand wringing is as unimaginative as it is unequivocal. Instead of draconian cutbacks in greenhouse-gas emissions, there may very well be fairly simple ways--even easy ones--to fix our dilemma. But the discussion of global warming never makes this clear; it seems designed to preclude any hint that we might remedy the situation except through great sacrifice, discomfort, and cost. Indeed, it seemingly assumes a direct relationship between the level of sacrifice, discomfort, and cost demanded by any proposed solution and its scientific efficacy. Solutions based on suppressing fuel use will cost us dearly, in terms of both dollars spent and standard of living. Economists differ over the price tag, with a rough analysis yielding an estimate of about $250 billion a year to reduce carbon dioxide emissions alone by 15 percent worldwide. (This number is easily debatable within a factor of two.) To this price we must add the cost of reducing other greenhouse gases, a cost felt not merely in our pocketbooks but also in the goods, services, and innovations whose production would be halted or forgone.
But for a number of reasons that I will discuss below, now is precisely the time to take seriously the concept of "geoengineering," of consciously altering atmospheric chemistry and conditions, of mitigating the effects of greenhouse gases rather than simply calling for their reduction or outright prohibition. While such a notion may seem outlandish at first blush, it merely acknowledges explicitly what everyone already understands: that human activity has an impact on the planet.
Forty years ago, the noted atmospheric scientist Roger Revelle declared that "human beings are now carrying out a large scale geophysical experiment" by pumping billions of tons of carbon dioxide into the air. The question before us should not simply be how best to stop the experiment--and, by extension, the prosperity and progress allowed by cheap, abundant energy.
Rather, the question should be how best to design that experiment, so that we maximize benefits and minimize costs. As the citizens of the advanced nations become convinced that global warming is an immediate threat worthy of response, they will legitimately ask for solutions that demand the least sacrifice.
Politics and Parasols
A little-noticed 1992 National Academy of Sciences panel report spoke directly to this issue. The report clarified the science behind global warming and then ventured far from the ruling environmental orthodoxy: Could we accept that greenhouse gases will rise and find ways to compensate for them? Instead of cutting gases, could we intervene to mitigate or offset the warming they may cause?
Climate modification is time-honored, though not clearly a winner. Cloud seeding in the United States during the 1940s and '50s met some success but ended in a blizzard of lawsuits from those who claimed their local rainfall had been diverted by neighboring areas. (Though such assertions had little scientific proof, courts felt otherwise.) During the Cold War, both sides studied a menu of climatic dirty tricks, including schemes to kill the opponent's crops.
These programs foundered on a fundamental fact: Before modifying a climate, one must first grasp it. At the level of understanding available in the 1960s, only spectacular interventions would have left discernible signatures. Climate variability was so little fathomed that weather prediction was pointless beyond roughly a week.
But in progress little noticed by the public, systematic weather prediction has advanced more than tenfold in its assured time range. By watching the sun, atmosphere, ocean, land, and clouds using satellites, advanced aircraft, ships, and a tight grid of land-based observations, we have diminished the uncertainties about long-range weather. We are still just talking about the weather, but the talk is of higher quality. Earlier this year, for instance, the National Oceanic and Atmospheric Agency predicted a coming wet winter six months in advance, based on temperature measurements of tropical waters, presaging a new El Niño ocean current. Whether that prediction is right or wrong--the coming months will decide--we are entering a new era in forecasting. With the latest systems, backed by heavy computer modeling, we will shrink uncertainties, identify subtle feedback loops, sniff out regional pollution patterns, discern the spread of deserts and the withering of forests.
Sensitive global measures of disturbance will shed further light on polar and glacial contractions, ozone levels, volcanic dust, levels of the oceans. There is even a technique available for cheaply gauging global reflectivity by measuring "earthshine"--the faint glow of our reflected light, seen on the dark portion of a crescent moon. Using a small telescope and makeshift gear, astronomers easily showed that we reflect 30 percent of incoming sunlight back into space--a number that our satellite system got earlier, at a price tag of hundreds of millions of dollars. Such innovation will lessen the costs and confusions of global understanding, a help we will need dearly if and when the greenhouse predicament worsens.
Some geoengineering systems appear possible to deploy now, and at reasonable cost. They could be turned on and off quickly if we got unintended effects. It would be relatively easy to run small-scale experiments to answer questions about how our current atmosphere behaves when one alters the kind of dust, or aerosols, in it. Nuanced knowledge is crucial; the biosphere is a highly nonlinear system, one that has experienced climatic lurches before (glaciation, droughts) and can go into unstable modes, too.
Indeed, some critics argue that this simple fact precludes our tinkering with the "only Earth we have." Earth's climate might be chaotically unstable, so that a state with only slightly different beginning conditions would evolve to end up markedly different: An engineered early frost this year might mean an ice age the next. But we also know that Earth suffers natural injections of dust and aerosols from volcanoes, driving weather changes. Experiments that affect the planet within this range of natural variability could be allowed with little to no risk.
The simplest way to remove carbon dioxide, the main greenhouse gas, is to grow plants--preferably trees, since they tie up more of the gas in cellulose, meaning it will not return to the air within a season or two. Plants build themselves out of air and water, taking only a tiny fraction of their mass from the soil. Forests, which cover about a third of the land, have shrunk by a third in the last 10,000 years (though they have grown over the last half-century in the United States, mostly due to market forces).