Here’s how to cut emissions of greenhouse gas: Shrink the economy, and burn less coal.
These lessons emerge in a March US Energy Information Administration report showing that human-induced emissions of GHGs by the world’s favorite global-warming villain fell by more in 2009 than in any year since records began in 1990.
Carbon dioxide, the main regulatory target, dominated the 5.8% decline.
EIA gives three primary reasons for the lower emissions: economic recession, the particularly heavy setbacks of energy-intensive industries, and fuel-switching by power generators to natural gas from coal, encouraged by falling gas prices.
Largely because of economic slowdown, the US rate of growth in energy-related CO2 emissions fell in every year since 2005 except 2007.
The energy intensity of the economy—the amount of energy consumed to generate a unit of growth—fell by an average of 1.9%/year over that period as well as during 1990-2005, when growth was faster (3.1%/year on average vs. 0.5%/year).
In contrast with the steady drop in energy intensity, carbon intensity of US energy supply, in what EIA says “may represent a new trend,” swung from an average increase of 1%/year in 1990-2005 to a 1.9%/year decrease in 2005-09. Likely reasons: gas displacement of coal and growth in the use of renewable energy to generate power.
These factors created a 7.1% drop in energy-related CO2 emissions in 2009, offset partly by increases in other GHGs.
Overall GHG intensity decreased by 3.3% in 2009, EIA says. That’s the difference between the 5.8% increase in total emissions and economic contraction of 2.6%.
These numbers stir memories of the global scorn former President George W. Bush received for emphasizing GHG intensity instead of hard emission targets pursued by taxation and regulation.
Evidently, improvement in GHG intensity has a role to play in the control of emissions and is achievable without a reengineering of the economy. The alternative seems to be foresworn prosperity, a strategy not destined to enjoy long-lasting political support.
(Online Apr. 1, 2011; author’s e-mail: firstname.lastname@example.org)