2.6 The international community got together to meet the problem head on.

Even while scientists were still trying to understand why the ozone layer was depleting, they knew they had to do something about it. In 1985, a group of experts from around the world met in Vienna to discuss ways to research and solve the problem. This set the stage for the international community to come together in Montréal in 1987, to produce a plan to deal with the problem of ozone depletion. It would involve sacrifices—notably, phasing out dangerous chemicals such as CFCs—and only two dozen governments signed on to the Montreal Protocol that September. By 2009, the protocol (treaty) was eventually ratified by all 196 countries in the world when East Timor signed on.

The Montreal Protocol, administered by the United Nations, outlined a series of deadlines over the next decade for cutting back production of CFCs. Governments would have to put in place their own plans for achieving a desired outcome, or policy, for reducing CFCs.

Policy has been described as translating our values into action. Science provides information we can use to make informed decisions to protect our health, safety, or environment. Society then decides what “ought” to be addressed (do we address ozone depletion?) and hopefully uses the best scientific information available to set reasonable policies that take into account the ecological, economic, social, and political issues at stake.

Concerns raised by researchers in the 1970s led to a ban on CFCs in most aerosol products in 1978 in several countries, including Canada. As evidence mounted, industry, the public, and governments began to realize the seriousness of this problem.

Canada passed its first regulation on CFCs in 1980 under the Environmental Contaminants Act. In 2001 an accelerated phase-out plan was developed. This plan is implemented by both Environment Canada and provincial governments.

Note that the 1987 Montreal Protocol and the international commitment to address CFCs and ozone depletion came before Susan Solomon’s definitive studies were published in 1988. This is an example of applying the precautionary principle—acting in the face of uncertainty when there is a chance that serious consequences might occur. By 1987, though we didn’t know all the details, we knew enough to take action. As more information poured in, it quickly became apparent that the Montreal Protocol targets would not be sufficient to stop ozone depletion. Amendments are still proposed and negotiated in annual meetings which strengthen the response and adjust the target dates to phase out harmful compounds. This is an ongoing process, and an example of adaptive management—allowing room for altering strategies as new information comes in or the situation itself changes. This same approach is needed to address other global environmental issues such as climate change. We cannot know the exact details of future climate change impacts before they occur but we do have a good idea of what we are facing. By acting now, we can lessen the severity of those impacts and adjust our response as we go along. [infographic 2.6]

Fortunately, companies that produced CFCs, such as Dupont, were already researching alternative chemicals in the lab that could serve the same purposes with less damage. If companies could sell a CFC alternative just as easily, then cutting back on CFCs would not hurt them financially. Still, some of the replacements, particularly some hydrochlorofluorocarbons (HCFCs) used in refrigerants, eventually would also prove to be detrimental to ozone. In addition, illegal stockpiles and old refrigerators continue to release some CFCs, though that amount is decreasing rapidly under the Montreal Protocol. Pockets of CFCs remain because of continued legal “essential” uses, for medicines and nuclear power, for example.

Today, ozone-depleting compounds in the stratosphere are decreasing at a rate consistent with the policy changes of the Montreal Protocol. Outside of polar regions, ozone levels declined through the 1990s but seem to be holding steady more recently. The Montreal Protocol has been hailed as the most successful international environmental agreement in history.

There is still much we don’t understand about the atmospheric chemistry of ozone depletion. Just when it seemed ozone was beginning to recover, the winter of 2004–2005 in the Arctic was unusually cold and ozone loss was very high that year. This was eclipsed by a record 40% loss of ozone over the Arctic in spring of 2011. And Antarctica set two new records for ozone depletion in 2006—the widest and deepest hole ever observed, with some areas near 90% depletion. What this tells us is that even though CFCs are declining, very cold winters will still give us years of higher-than-expected ozone depletion. [infographic 2.7]

Future projections estimate that midlatitude areas should be back to pre-1980 ozone levels by 2050; polar regions should be back by 2075, though the next 15 years should show periodic large declines and produce large “ozone holes” in very cold years like those seen in 2006 and 2011. Although she retired from NOAA in 2011, Solomon continues her research on CFCs, and is both hopeful and realistic. “It’s clear that ozone will ultimately recover but it’s also clear that it will take many decades to do so,” she says. “It has been a real privilege to work on such an interesting problem and to feel that the world found it useful in making choices about the Montreal Protocol.”