How Much Warming Will the President’s Plan Avert? (Hint: It’s way too small to be detected or verified)

President Obama unveiled his Climate Change Action Plan at Georgetown University today. As expected, the President advocated carbon dioxide (CO2) emission standards for new and existing coal-fired power plants, tough new energy efficiency standards for homes and appliances, and federal support for private renewable energy investment on public lands.

Congress’s failure to approve his plan would have “a profound impact on the world that we leave behind not just to you, but to your children and to your grandchildren,” Mr. Obama contended.

The President’s plan, however, provides no specifics on the EPA’s pending power plant emission standards, nor does it estimate how many tons of CO2 emissions those standards will avoid or reduce.

Surprisingly, the 21-page plan contains only four emission reduction estimates. The administration’s fuel economy standards are projected to avoid 6000 million tons of CO2; appliance efficiency standards, 3000 million tons; heavy truck fuel economy standards, 270 million tons; and improved forestry practices, 140 million tons. The grand total of itemized CO2 reductions is 9,410 million tons.

How much climate change will that avert? Too little to be detected or verified. 

Cato Institute climatologist Chip Knappenberger provides a plausible way to calculate the global warming mitigation effect of any CO2 reduction proposal. He describes the underlying methodology here.

Suffice it to say, the key factors one must nail down are (1) the relationship between CO2 emissions and atmospheric concentrations, and (2) the relationship between concentrations and global temperatures.

Using both empirical correlation (how atmospheric CO2 concentrations and global temperatures have changed over time) and the mid-range of climate model sensitivity assumptions, Knappenberger deduces that it takes 1,767,250 million metric tons of CO2 (mmtCO2) to raise the global temperature by 1.0 degree C.

Thus, to estimate how much global warming the Obama plan (or at least the quantified portion of it) will avoid, we divide the emission savings — 9,410 mmtCO2 — by 1,767,250. The plan will avert 0.0053°C of global warming. Planet saved!