The Montreal Protocol, a Little Treaty That Could

By JUSTIN GILLIS

Here is a remarkable fact about global warming: It might be twice as bad right now were it not for a treaty negotiated by a conservative American president, for an entirely different purpose, based on motives no one has ever quite understood.

That treaty is known, in shorthand, as the Montreal Protocol. Its formal purpose is to save the ozone layer in the upper atmosphere, which protects the planet and its people from debilitating levels of cancer-causing ultraviolet radiation.

The negotiations on behalf of the United States, in the 1980s, were carried out by the Reagan administration. And the treaty is turning out to be one of the more momentous steps Ronald Reagan took as president.

The Montreal Protocol is widely seen as the most successful global environmental treaty. It incorporates pragmatic, business-friendly principles that have allowed it to operate smoothly for more than two decades, achieving its goals — and then some — with little controversy.

To those paying attention, all of that has been known for years. Now comes a new piece of science, though, saying that the treaty may be even more important in limiting global warming than we thought. It is a timely paper, since a proposal is on the table to rejigger the treaty in a way that could help us still more in slowing the rate of climate change.

The story began in the 1970s when two scientists working together in California, Mario J. Molina and F. Sherwood Rowland, realized that a commonly used group of industrial chemicals posed a frightening hazard. The chlorofluorocarbons, used in refrigerators and air-conditioners and as propellants in products like hair spray, were drifting into the upper atmosphere and breaking down in ways that were thinning the ozone layer.

In short, Dr. Molina and Dr. Rowland had discovered a global environmental emergency. Continued use of the chemicals threatened society with huge increases in skin cancer, damage to crops and many other problems.

The work would eventually merit the Nobel Prize, but that did not prevent a tortuous political battle over the issue. Some of the same people who deny global warming now took money from the chemical industry back then to challenge the science. But the stunning announcement by British scientists in 1985 that an actual hole in the ozone layer had appeared over Antarctica caught the public imagination in a way few scientific discoveries do, ramping up the demands for action.

Mr. Reagan, with his zeal for deregulation and his conservative business principles, might have been expected to fight the idea of a global treaty. That is exactly what many of his closest aides wanted him to do. In the end, he rejected their advice and backed it, vigorously.

Why? One idea is that Mr. Reagan himself had had skin cancer, and allowed a concern for public health to triumph over ideology. Eli Lehrer, the head of a Washington think tank called the R Street Institute and a longtime Reagan admirer, offered me a simpler theory: that the man truly loved nature. He was never happier than when riding horses and chopping wood. Perhaps the science of the ozone hole just spooked him. We know it spooked Margaret Thatcher, the British prime minister and Reagan ally, who had been a research chemist in her early life.

The Montreal Protocol on Substances That Deplete the Ozone Layer entered into force on Jan. 1, 1989, and in the years since, it has been used to phase out nearly 100 dangerous gases.

Now, the wheel of history often turns on chance, and here is one of the great coincidences of our time: Many of the substances that destroy the ozone layer also happen to be exceedingly powerful greenhouse gases.

If production had been allowed to continue, a batch of scientific studies show, the planet would most likely be warming a lot faster than it is. The latest of these studies came out only a few weeks ago. Led by Francisco Estrada of the Autonomous National University of Mexico, the paper suggests that the slowdown in global warming that has occurred over the past 15 years is a direct result, at least in part, of the success of the Montreal Protocol.

In fact, the evidence suggests the protocol has done far more to limit global warming than the better-known treaty adopted for that purpose, the Kyoto Protocol.

Could it do still more?

It turns out the gases phased out under the Montreal Protocol are being replaced by another set of chemicals, hydrofluorocarbons. They do not destroy the ozone layer, but they are potent at causing global warming.

Prodded by small island countries concerned about drowning on a warming planet, nations are considering an amendment to the Montreal Protocol that would phase out the worst chemicals in this group in favor of new ones that are safer for the climate.

For years, big developing countries have been holding out, for they have important industries tied to hydrofluorocarbons. But China came on board over the summer, and the Obama administration is cajoling the last big holdout, India, at this very moment.

It seems to be a matter of time before the deal gets done, and if it does, the projections say we will gain substantial climate benefits this century. Once again, amid all the paralysis over climate change, the Montreal Protocol will have proved to be the little treaty that could.

Durwood Zaelke, who heads a Washington advocacy group called the Institute for Governance and Sustainable Development that is pushing for the treaty amendment, told me he drew a simple lesson from all this: However overwhelming global warming may seem at times, we are not powerless in the face of it.

Read the original article in The New York Times here.