Few government policies have longer lead-times than those dealing with infrastructure development. This is demonstrated through the 17-year time-frame from design to deployment for Britain’s replacement Trident subs and it pertains directly to climate change issues. Despite Nicholas Stern’s espousal of a fossil fuel free society by mid-century, fossil fuel based plants are still in construction around the world. Right now, coal power plants account for about 1/4 of all human caused greenhouse gas emissions. About 150 new plants are slated for construction in the United States alone: 56% of them coal fired. By the time they have been completed, operate, and reach the end of their operational lives, we will be getting pretty close to 2050. All told, the International Energy Agency predicts that global coal use will rise by 71% by 2030, raising greenhouse gas emissions with it.
Even if we cannot go straight to infrastructure based entirely around renewables, we can make some modest investments now that could save us a lot of trouble in the long term. One example is building coal plants that can be easily converted to “Oxy-fuel” systems. In these, coal gets burned in nearly pure oxygen. The products of that reaction are mostly pure carbon dioxide, which can then (theoretically) be sequestered underground. By eliminating the need to separate CO2 from other gases, before sequestration, such plants could save a lot of money. Of course, they do require a system to extract oxygen from air to feed the reaction, though this is apparently easier to pull off.
Such transition technologies might be the trickiest part of the entire move away from fossil fuels. Renewables seem as though they will eventually mature, allowing some mix of solar, hydro, and related systems to power the grid. Transition technologies are critical for two other reasons, as well: both China and the United States are concerned about energy security and have masses of native coal, and fast-growing developing countries are unlikely to be able to make the kind of costly commitments to low-carbon energy that developed countries will. Managing interim emissions, and trying to stay below the 550ppm level that the Stern report has highlighted as highly dangerous, will be a considerable challenge.