In the last two years or so, I have witnessed what I believe to be a sea change in society's views about the environment, and particularly the acceptance of global warming by the mainstream as a critical challenge of our era. When faced with the questions of whether this surge of popularity of "green" issues was just a fad, I confidently answered that no, this time things were different. Progressive thinking about environmental issues had penetrated the mainstream. Even President Bush acknowledged the issue in his 2007 State of the Union address. A new generation of children would grow up with sustainability as the norm just as my generation grew up with computers as the norm. But today, I fear that we may see a major setback in 2009. The combination of recession and populist notions will gain momentum, stoked by fear and hardship. These forces may be strong enough to stop the progress of environmentalism dead in its tracks. The essential problem is the tragedy of the commons. Global warming and concern about CO2 emissions is a global, social problem that has extraordinary long term impacts but when you look at it on an individual level, the marginal returns that a selfish individual can gain by ignoring the greater good far exceeds the marginal cost to that individual in the short run. In the long run, though, everyone pays more. For those not familiar with this concept of economics, an example that everyone has experienced is the group dinner where everyone agrees to split the bill. Relieved of their individual accountability to pay for only what they use, each person orders more than what they would normally order, knowing that the additional costs will be borne by the group. The individual also reasons that if they alone behave responsibly, they will not be rewarded with a lower bill but rather will still have to bear the higher cost of the average bill. The predictable result is that the average bill is much higher than if each paid their own way. A nasty side effect is paranoia and suspicion, as people watch what their friends are ordering and get angry at the irresponsibility of each other. With recession upon us and fear of long term depression, powerful populist notions will challenge the "greater good" notions of environmentalism. Put simply, if people are out of a job and can't afford to pay their heating bill, they could give a rat's ass about global warming and will be infuriated by billions in government spending for environmental causes including electric car subsidies and investments in solar power or biofuels. The media loves to play the populist line, as it is a sure winner for readership. Politicians are highly susceptible to populist trends, and will be quick to change directions. You will hear a lot of politicians saying, "I support these environmental causes and issues in the long run, but the people can't afford them today." What first triggered this thought for me was the not-so-friendly response that I received to my blog on the need for a gasoline tax. One commenter even went so far as to call for my hanging! Then this morning I read in the New York Times that cheap coal is making a resurgence for home heating. Watch this play out in 2009. The media will stoke the fires of populism and environmentalism will come under fierce attack. In the absence of private capital to fund major investments in advanced technologies to reduce CO2 emissions, the government will come under intense political pressure if it tries to step into the breach. Great courage will be needed to stay the course of tackling long term global challenges while also addressing the short term economic hardships.