Carbon is intense
Stuart Gaffin is a climate researcher at Columbia University and is a regular contributor with his blog “Exhausted Earth”. ThomsonReuters is not responsible for the content – the views are the author’s alone.
On April 16 President Bush gave a speech laying out a new United States climate policy goal – stabilizing US emissions by the year 2025.
During the course of this speech the President reported as progress a previous goal he had announced in 2002: that the “carbon intensity” of the US economy under his administration has been declining at the rate of about 18% per decade — the rate he targeted in 2002. Carbon intensity is the amount of carbon emitted by US fossil fuel combustion per dollar of US economic output.
There has been both just and unjust criticism about using this benchmark for progress on US climate. Just criticism is the fact that the US economy has long been ‘decarbonizing,’ including under the Clinton Administration, at a little less than 18% per decade, without any climate change policies.
The forces driving this include continual improvements in energy efficiency, structural changes in the economy like the growing information technology sector and environmental concerns unrelated to climate, like air pollution control. Therefore the US administration did not make clear to the public the actual meekness of the 2002 goal.
The US administration should not be faulted however for focusing on carbon intensity as a key metric for progress, in addition to total emissions. Carbon intensity must indeed drop if we are ever going to control emissions. It just has to do so fast enough to offset economic growth.
So, for example, the new goal of stabilizing US emissions in 2025 simply means carbon intensity has to decline at the same rate as US economic growth then: if the economy is growing at say 3%, then carbon intensity must decline at 3%. Eventually, to bring actual US emissions down, the intensity will have to decline at a faster rate than the economy is growing.
Indeed, we ought to be speaking much more about carbon intensity so that it attains the same familiarity in the public mind as economic growth rates and population growth rates. It is going to be one of the most important economic and environmental numbers of the 21st century.