Thursday, October 4, 2007

Carbon emissions can come down ... and did

A May report by the U.S. Energy Information Administration gave preliminary evidence that total energy-related CO2 emissions in the U.S. fell by 1.7 percent from 2005 to 2006. If the numbers hold up to subsequent revisions, that's very good news.

There are short-term and long-term explanations behind the numbers. The biggest short-term explanation is that the weather in 2006 was milder than in 2005. The winter was warmer, while the summer was cooler. This led to fewer heating and cooling days. Accordingly, the biggest decrease in energy-related CO2 emissions in both absolute and percentage terms occurred in the residential sector, where emissions dropped by 3.7 percent.

While year-to-year temperatures can go up and down, the long-term trends give some reason for optimism. Overall, the U.S. is continuing to become more energy- and emissions-efficient. Energy-intensity (units of energy per dollar of total economic ouput) fell by 4.0 percent from 2005 to 2006, and carbon-intensity (CO2 emissions per dollar of output) fell by 4.5 percent. Since 1990, the EIA reports that carbon-intensity dropped by more than a quarter, or just under 2 percent per year. At least some of this can be explained by restructuring in the economy and the steady shift from industrial activity to services and other types of commercial activity.

Another positive trend is that the long-run overall growth in emissions appears to be slowing. Since 1990, overall emissions have grown by about 1 percent per year. However, since 2000, there has only been one year (2004) with emissions growth above 1 percent. Emissions declined in 2001, partly due to the recession and partly due to the brief transportation shut-down following the 9/11 attacks. After 2001 though, growth in emissions has been very modest; this occurred despite relatively strong growth in the economy.

The short- and long-term pictures would be brighter still were it not for the transportation sector. Transportation has overtaken the industrial sector as the largest contributor to emissions. Since 2000, the growth rate in transportation emissions has been nearly triple the growth rate of residential emissions and 50 percent higher than the growth rate of commercial emissions. Energy-related CO2 emissions continue to be dominated by the use of petroleum.

Both sides of the climate change debate should be cheered by these numbers. For the stay-the-course crowd, the numbers show that regular market and technological forces, and perhaps voluntary action, can slow the production of greenhouse gases. For the policy-change crowd, the numbers show that zero growth and even reductions in energy-related CO2 emissions may be more easily achievable than we might have thought, and that reductions can occur without driving the economy into recession. The numbers also seem to justify a special focus on improving the efficiency of the transportation sector.


eredux said...

Check out this US Carbon Footprint Map, an interactive United States Carbon Footprint Map, illustrating Greenest States to Cities. This site has all sorts of stats on individual State & City energy consumptions, demographics and much more down to your local US City level...

Doug Johnson said...

Dave Rumor, you stated below, you had not heard of gobal freezing,My children where in college in 1993
1994 and all they heard from the liberal professers was gobal freezing. Some how I think you are at least 36. Second you did a counterpoint about the war. Someone asked you how many times you had been over there? I missed the answer.

Dave Ribar said...


My comment (for another post) was "The New Ice-age stuff was a little before my time. I don't recall the same level of concern, certainly not to the same extent as the most recent NAS reports." If you could point me to a NAS or UN scientific report warning about an impending ice age and recommending action (as the current reports do), I would be happy to look it over.

When I was in college I do recall discussions about the possibility of a nuclear winter, but that was not the same thing.

I did do a N-R counterpoint and several blog columns about our occupation of Iraq. I have not been to the country.

Doug Johnson said...

I am not going back 25 years for nothing!The UN and tits on a boar hog, both are useless.If you have not been to Irag then every thing you say is hear say. It may are may not be fact. Just a short time ago you liberals where using Jesse Mac Beth as your ear mark. Now he is a proven fraud. I was against this war from the get go, still am. Now we are in it, we need to win this thing. Gobal warming, I think it is real, however I hear no bitching bout China, Mexico, are India. The real bad boys, only Bush did it. Where all the hurricanes that the lame stream media and NASA said we where to have? Season all most over.

Dave Ribar said...


Not sure what any of this has to do with this column. If you want to raise issues that you can substantiate or that have something to do with the actual column, I'd be happy to continue the conversation.

PS. I haven't been there, but I think the conventional spelling is "Iraq."