If you traveled 10 miles straight up from wherever you are at the moment, you’d enter our planet’s stratosphere. In that rarified air lies Earth’s ozone layer, a kind of protective sheath that absorbs most of the sun’s ultraviolet radiation. But in the 1980s, scientists noticed a growing hole in that ozone layer forming above Antarctica, and were able to link ozone depletion to chlorofluorocarbons (CFCs), used in industry and in consumer products as a propellant or refrigerant. But just three years after this link was discovered, the world came together to sign the Montreal Protocol, which curbed the use of these destructive CFCs, and the hole above Antarctica slowly stopped growing in size. Now, a new study published in Nature this week says that hole is finally starting to shrink. The New York Times reports:
[The study] also reinforces that the Montreal Protocol has been a “resounding success,” [said David Fahey, a researcher at the NOAA]. “It stands head and shoulders above any other environmental treaty.” […]A 2009 analysis by NASA scientists showed what the world would have been like had there been no Montreal Protocol, and CFC production and use had continued. By midcentury, their simulations showed, the ozone hole would have covered the world, and at noon on a clear summer day in a city like New York, the UV index, a measure of the damage the sun can do, would have caused a noticeable sunburn on unprotected skin in 10 minutes.That dire situation has been avoided thanks to society’s collective efforts, [the study’s lead author Susan Solomon] said. “We are seeing the planet respond as expected to the actions of people,” she said. “It’s really a story of the public getting engaged, policy makers taking action, and business getting engaged.”
Scientists are right to laud this as an extraordinary accomplishment for the international community, and a positive example of a global environmental treaty fixing a problem of enormous scale. But let’s not make the mistake of using this as evidence that international treaties can solve all of the planet’s eco-woes. We can apply very few lessons from this ozone solution to the battle against climate change. Here’s why.For one thing, the mechanisms behind ozone depletion and the actual evidence of its occurrence were obvious, measurable, and straightforward. We could see this hole growing above the south pole, and scientists were able to link it clearly to CFCs. Compare that to climate change: Yes, we understand that greenhouse gases (GHGs) trap more of the sun’s radiation, which should lead to rising surface temperatures, but that’s been much harder to measure empirically. Our best climate models have proven to be woefully inadequate for the task of predicting what these changes are actually going to look like. Despite the claims of fear mongering greens, climate science is far from settled—we know far less about the workings of the planet’s climate than we do about our ozone layer.Moreover, the solution to the ozone depletion problem was a lot more straightforward than what we’re currently looking at for mitigating climate change. Industry was able to identify alternative refrigerants and propellants that could effectively replace CFCs without breaking the bank. With climate change, so many industrial processes and forms of power production emit greenhouse gases that trying to completely phase out CO2 and methane emissions looks like a borderline impossible task. Perhaps more importantly than the scale of the GHG problem is the lack of a cost-effective alternative for the myriad processes that actually emit these climate change forcers. That’s why so many of the solutions environmentalists have proposed for limiting GHG emissions involve hamstringing growth—we haven’t figured out a way to flourish sustainably yet.That isn’t to say that we won’t ever find the solution we need to grow green; many countries are already doing just that, and as the developed world moves towards a less energy-intensive information economy we can expect that trend to continue. Moreover, as the pace of technological change accelerates, so too does the likelihood of a breakthrough that could fundamentally change the climate-change calculus.But as things stand, we lack both a deep understanding of climate change as well as cost-effective solutions to the problem—two things that the Montreal Protocol had going for it. So let’s applaud the success of that 1987 treaty, but keep in mind that no one is going to be looking at the document created in Paris last December with the same kind of admiration.