PERSPECTIVE ON THE ENVIRONMENT : A Global Warming Middle Ground : Even if the environmental Chicken Littles are right, technology may enable us to retrofit the ozone layer before the sky falls.
What career will your toddler pursue? Where will the Dow Jones close on the day you retire? No one seriously predicts such things. You would laugh at someone who tried. But the unpredictability of the future doesn’t stop you from planning for your child’s education or your own retirement.
Today, the House subcommittee on energy and environment plans a debate over predictions of future climate change. Activists and skeptics will clash over the recent announcement by the U.N. Intergovernmental Panel on Climate Change, which projects unprecedented changes in future climate and finds that signs of such change already have been detected. Each side will strive to persuade us that it knows whether the climate will be a serious problem over the next 100 years and what we should do about it.
The fact is, however, that there is no reason to believe either side. Climate change is a classic example of a problem involving complex, non-linear systems, with many interacting processes ranging from the large (global emissions of infrared radiation to space) to the minuscule (formation of cloud drops on tiny aerosol particles). Changes in climate are difficult to predict because many small- scale processes can influence the large ones. Even the computers of tomorrow will not be powerful enough to model them all.
Worse, predictions about the consequences of climate change depend on guesses about society and technology decades hence. Warming may or may not destroy certain crops. It may or may not benefit others. It may or may not spread tropical diseases to temperate zones. On the other hand, if even a few environmentally benign technologies such as solar energy or electric cars fulfill their promise, climate change could become a non- problem. Recall that many Americans in the 1890s worried that in the 1990s, city streets would be buried in horse manure.
Both sides of the current debate offer policies based on their predictions. Advocates generally favor stabilizing emissions, while skeptics oppose reductions. Either could be the right answer or the exceedingly costly wrong one. We have no way to know.
Yet there is a reasonable alternative--an adaptive strategy that combines preparation and flexibility. An adaptive strategy for climate change assumes from the outset that our choices will change over time. Our research groups at RAND and the University of Illinois have used rigorous computer analysis to estimate the costs and compare the results of three approaches-- emissions stabilization, “do a little” emissions reductions and an adaptive strategy--over a huge range of plausible climate-change futures. Since we cannot predict future climate change with certainty, the adaptive strategy emerged as by far the most prudent and cost-effective.
A successful adaptive strategy for climate change will contain two key elements. First, we must carefully monitor for signs that climate changes are sufficiently serious to warrant a major response. The recent scientific consensus that some climate change has been detected is a start, but only that. Rather than debating goals for near-term emissions reductions, experts and officials should develop a consensus on which changes would require action. For example, decreases on the order of a few tenths of 1% of gross world product (an amount much above the damages recorded in recent years) might be the appropriate trigger. And governments must adequately support the scientists and equipment needed for the monitoring effect. Congress has recently cut such funding; it should be restored.
Second, we must hedge by developing better response options. Halting serious climate change could require massive reduction of emissions, not just near-term stabilization. The world would have to eliminate most fossil fuel consumption-- such as coal-fired power plants and gasoline-powered automobiles--somewhere around the middle of the next century. To facilitate such reductions if they are needed, governments should now support research on environmentally benign technologies, eliminate market-distorting subsidies for oil and coal that artificially discourage private investment in non-polluting energy sources and encourage conservation.
No matter what the future holds, the adaptive strategy is the best response to an unpredictable threat.
