It’s a poor indicator of progress on global warming
The statement from spokeswoman Kristen Hellmer said the United States is “well on track to meet the president’s goal to reduce greenhouse gas intensity of our economy 18 percent by 2012.”
This statement makes it sound like the Bush administration is taking on the problem of climate change head-on, with an aggressive program to reduce emissions.
But it ain’t so.
The statement is about greenhouse gas intensity rather than greenhouse gas emissions.
Greenhouse gas intensity is the emissions per unit economic output. Multiply this quantity by the size of the economy and you get total greenhouse gas emissions.
Historically, U.S. greenhouse gas intensity has declined all by itself as our economy has evolved from manufacturing (which takes a lot of energy) to services (which take less), and as equipment has naturally become more efficient. Over the past few decades, greenhouse gas intensity has declined somewhere between 1% and 2% per year.
At the same time, the economy has grown more rapidly than this, so total greenhouse gas emissions have increased.
Several years ago, the Bush administration committed itself to an 18% decrease in greenhouse gas intensity over a decade — corresponding to a decrease of about 1.8% per year. This represents negligible if any increase in the natural rate of decline.
In other words, they basically committed the U.S. to maintaining the status quo.
Importantly, it is virtually certain that the economy will grow faster than this during the decade, so even if the target is met, greenhouse gas emissions will continue to rise. Considering that we need to reduce emissions by about 80% from today’s levels to stabilize atmospheric CO2, achieving the administration’s intensity target does nothing to stop global warming.