
A scientist friend posted a link to a new paper in Physics Today (“The Antarctic ozone hole: An update“) about the history of ozone depletion. It was an unexpected crisis met with a surprisingly quick and effective response. As they say, “Although the year-to-year meteorological variability is too large for us to be able to declare that the ozone hole is closing, figure 5 [shown above] makes clear that the Montreal Protocol prevented substantial worsening of ozone loss in Antarctica and worldwide.” It’s a happy environmental story, from a year where things like hydraulic fracking and the appalling pollution of the Ganges in India get frequent media exposure.
The final paragraph concludes with the statement “[the ozone hole’s] disappearance will symbolize the possibility of protecting Earth through cooperative actions” (emphasis mine). Quite optimistic, and an indirect but obvious reference to the ongoing political struggle about CO2 and its role in anthropogenic climate change.
So, the question then: is carbon fundamentally a different beast than other atmospheric pollutants? In the United States, CFC emissions are a small fraction of what they were just three decades ago. SO2 emissions, which contributed to devastating acid rain in the Rust Belt and the Northeast, have plummeted since the cap-and-trade market implemented in 1990; the issue still exists, however, as the graph below shows the influence of China on total emissions. Clearly economic forces can in some cases react to environmental catastrophes.

Million dollar question: is carbon dioxide and its compatriots a different beast? Is it too much to think we will see similarly upbeat reports in the future?
A couple things I think may create separation between acid rain and climate change. The first is the question of time. Acid rain quickly became a serious industrial problem, and its effect came quickly and was obvious. Nobody could look at a forest with dead trees, next to a lake with no fish, and handwave it away.
Climate change is real, and it’s going to get a lot worse. When will it have its acid rain moment? It’s still too early to shove navel-gazing legislators, particularly in developed countries who have the economic power to shift global environmental policy. Kiribati just bought a chunk of land thousands of kilometers away, because the future does not look good for Kiribati as a home in the future. AOSIS is an example of serious state-level demand for radical solutions. The countries involved also almost no political clout. Powerful solutions will, at least for now, be done at the leisure of wealthy countries.
Another point is whether certain pollutants are more economically integral than others. CFCs were replaced relatively quickly, and today nobody misses them. Replacing fossil fuels means overhauling transit, power generation, and economic production. Collectively, it’s pretty much anything involving energy. Alternative tech exists, but it needs to show up in poor, rapidly expanding regions. The single best bit of information about the politics of climate change is this 2012 infographic by Al Jazeera English. Deadlock revolves around developing countries wanting large cash transfers (1% of wealthy states’ GDP, or about $168 billion annually for the US) to buy into emissions treaties, and the G8 and company wanting nothing of the kind.
There is good logic in the idea that if reducing greenhouse gases were easy, it would have been done already. Even modest claims about economic costs, a couple percent of global GDP, is trillions of $USD every year. But right now there seems to be very little of the “cooperative action” that the ozone report co-authors suggest. I have suggested in the past (paper posted on Scribd), that a revenue-neutral carbon tax could be a way to reduce emissions on the state level without a large-scale treaty, but that’s speculative and definitely in the optimistic vein that permeates the report quoted. The issue is massive, the sources of global warming diverse. The choice is between the “Expected future” and “World avoided” at the top of this article.