Noah Smith has a nice article at the Atlantic about some trends that surprise. One is CO2 emissions: "Old trend: souring US CO2 emissions, New trend: plummeting US emissions." He cites a blog post from the American Enterprise Institute, which links to a figure on per-capita CO2 emissions. But data from the Energy Information Agency, cited therein, clearly show that emissions from fossil fuels have declined recently, but that they are still 5% greater than in 1990. So, while per-capita emissions have fallen quite a bit (indeed, plummeted), total emissions from fossil fuels have grown. I've reproduce some of those data from EIA here:
It is encouraging that CO2 emissions per person are falling, but as our population has grown, total emissions continued to inch up until about 2005 or 2006 then began a downturn around 2007. Coal CO2 emissions peaked in 2005 while petroleum emissions peaked in 2006 while natural gas CO2 emissions grew through 2012. That these trends have continued suggests that a large portion of the decline is due to fuel substitutions (particularly natural gas for coal) in addition to the economic downturn. The bottom line on this post, though, is to be careful with units; total CO2 emissions (not per capita emissions) are what matter if you're concerned about atmospheric concentrations.
No comments:
Post a Comment