Can Obama's clean energy plan save the climate?

Mr. Tillerson believes that the best way to boost clean energy is to impose a carbon tax, a belief shared by Al Gore; Obama’s Energy Secretary-designate Steven Chu; and Obama's economic adviser Lawrence Summers, but not by Obama himself, who supports a cap-and-trade scheme.

But will it do the trick?

Assuming that the US actually could double alternative energy production by 2012, how far would that go toward solving the climate crisis?

A little. According to the US Department of Energy's Renewable Energy Data Book [PDF], 9.4 percent of total US energy production – this includes both electricity and transportation – comes from renewable energy sources, mainly hydropower and biomass. (Another 11.7 percent comes from nuclear power, which is not mentioned in this plan.) Check out this chart of US energy production from the book:

The remaining nonrenewable energies – oil, coal, and natural gas – contributed to the roughly 7 billion metric tons of carbon dioxide equivalent greenhouse gas emissions that the US belched out in 2007, according to the Energy Information Administration.

Let's be wildly optimistic and assume that every single one of these new geothermal stations, solar concentrators, and windmills will take a bite out of the most carbon-intensive source of energy: coal.

Coal accounts for one-third of US energy production, and, according to a 2006 spreadsheet by the EIA, emits about 2,300 million metric tons of CO2 equivalent, which is about one-third of the total. So if the US were to increase renewables to account for 10 percent more of our overall energy production and reduce coal production by the same proportion, then we'd reduce our total greenhouse gas emissions by about 10 percent.

I'm making two other huge assumptions here. First, that US energy production won't change at all except for the increase in renewables, and second, that all of these wind turbines and solar power stations have a negligible carbon footprint. In other words, this 10 percent figure is probably too high, unless the US also makes major improvements in energy efficiency.

And it's not enough to curb climate change, even if every other country effected a similar emissions reduction.

According to the UN’s Intergovernmental Panel on Climate Change’s Fourth Assessment Report, if the world’s wealthy countries were to cut their  emissions by 25 percent to 40 percent below 1990 levels (US emissions are now about 15 percent higher than they were in 1990), carbon dioxide concentrations would stabilize at 450 parts per million, the figure that the UN panel believed was the safety threshold.

But a report [PDF] by top climate researchers published last year in The Open Atmospheric Science Journal found that the UN panel ignored crucial feedback loops. The true safe threshold, they said, is 350 parts per million. This number, the report concluded, should be respected “[i]f humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted.”

Current atmospheric greenhouse concentrations are at about 387 parts per million and rising.

So a 10 percent emissions reduction is a modest start, and getting up to 25 percent renewables by 2025 would be another baby step, but if the world's leading climate scientists are right, these by themselves won't be enough to save us from catastrophic climate change.

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