One evening decades ago, when the atmospheric chemist Sherwood Rowland returned home from a long day at the lab studying chlorofluorocarbons (CFCs), his wife asked him how things were going. He replied that his work was going well "but it looks like the end of the world.” He was referring to his experiments showing that CFCs could break down high in the atmosphere when bombarded by sunlight, setting off a chain of reactions that could consume the ozone layer protecting earth's inhabitants from deadly UV radiation.
In 1974 Rowland and Mario Molina published an article describing the scenario. At first it seemed hard to believe, to put it mildly, that a substance found ubiquitously in everything from spray cans to air conditioners could be destroying a vitally needed part of the atmosphere. But two years later a National Academy of Sciences panel declared the research sound, and within a decade field meteorologists determined that atmospheric ozone has decreased 35 percent in 20 years. In 1987, just 13 years after publication of the first seminal article, 24 leading nations agreed at Montreal on a plan to phase out use of CFCs.
Five years later, in Rio, nations adopted a treaty in which they pledged to prevent "dangerous" climate change. And five years after that, in Kyoto, they agreed on a phased plan to reduce greenhouse gas emissions, in which the advanced industrial countries would make scheduled cuts by the year 2012, the developing countries only later. Perhaps because the path to Montreal had been so surprisingly smooth and action pursuant to the Montreal Protocol so prompt, expectations about the Kyoto Protocol to the International Framework Convention on Climate Change were naive.
In hindsight, it is easy to see that the problem of climate change is much more complicated than the ozone problem, and that approaches to the problem would be much harder to define and justify. This is a dilemma the expert community still is struggling to address.
The pathway from a hairspray can to global ozone depletion—however counter-intuitive at first glance—was direct, unambiguous, and relatively easy to demonstrate once postulated and recognized. Greenhouse gas emissions, by contrast, affect climate in multifarious ways, with numerous positive and negative feedbacks that that are hard to scope comprehensively and easy to argue about.
The problem of ozone depletion could be addressed and solved simply by eliminating CFCs, at a readily definable cost. Global warming cannot be slowed by just one expedient, and climate change cannot actually be stopped in the short or medium term. The nature and scope of the problem is open to debate, which implies that the costs of addressing it could range from modest to absolutely unaffordable.
Then too there is the profoundly divisive issue of who needs to get involved globally in finding solutions to climate change, and how. In the case of CFCs, they were widely used only in the advanced industrial countries, and so it was only necessary for those countries to agree on how to solve the problem. With carbon dioxide, the developing countries do not see why they should sacrifice growth prospects because of a problem largely created by the rich countries, and the rich countries do not see why they should take costly measures only to see their efforts undone by fast-growing emissions in the most rapidly modernizing poor countries.
My son, who is a college sophomore at a rather liberal-minded state university, tells me that a fatalistic attitude toward climate change has settled in among his fellow students: Since we can't actually stop global warming, why spend lots of money trying to merely slow it? Why not spend that money instead of things that can get fixed, and just get ready to adjust to climate change, however bad it turns out to be? This seems to me the nub of the political problem. Climate policy analysts need to better make the case for reducing the risks of climate change at costs that are not too onerous.
Rowland died on March 10, having been awarded the Nobel Prize for his pathbreaking work on CFCs with Molina and Paul Crutzen. Crutzen, despairing that the world will ever take effective measures to reduce greenhouse gas emissions, has become a crusader for climate modification.