On the Greenhouse Gas Emission Roller Coaster

by Bill Chameides | May 14th, 2010
posted by Erica Rowell (Editor)

Permalink | 1 comment

U.S. emissions from energy use were down in 2009 … by a lot.

The newly released climate bill by Senators John Kerry (D-MA) and Joe Lieberman (I-CT) targets greenhouse gas emissions for a 17 percent decrease by 2020 relative to 2005 emissions. That’s basically the same as the 2020 target in the Waxman-Markey bill passed last June in the House and the reduction pledged by the United States in the Copenhagen Accord (more on the accord here and here).

Is the target realistic? Maybe we can get a hint by taking a look at where our nation’s carbon dioxide (CO2) emissions have been and where the experts think they may be going.

U.S. CO2 Emissions from Energy Use Since 1990

Percent change from 1990 to 2007: +19 (U.S. Energy Information Administration, EIA)*

Percent change from 1990 to 2009: +8 (EIA)*

Why is the increase relative to 2009 so much smaller than that relative to 2007? The Great Recession, of course.

Economic downturns are painful and the one we’re currently struggling to climb out of is especially so. But they do tend to bring some positives. One of them might relate to longevity — amazingly, a 2009 study found that our life expectancies increase during economic busts and decline during booms.

It’s also the case that pollutant emissions decline during economic downturns. Here’s what happened during the most recent one.

Percent change from 2007 to 2008: -3 (EIA [xls file])
Percent change from 2008 to 2009: -7  (EIA [xls file])

Projections of Future U.S. Emissions from Energy Use

So our emissions are going in the right direction. But will they continue?

Most economists see the U.S. economy rebounding in 2010 and beyond and, accordingly, the EIA projects U.S. greenhouse emissions will resume an upward trajectory. But the average annual rate of increase [pdf] will only be 0.3 percent. That’s not bad, but is it good enough to meet the goals of a 17 percent  reduction by 2020?  Consider these numbers:

2020 EIA projected U.S. energy-related emissions: 5,851 million metric tons (EIA, Table 18)

Change relative to 2008: ~0 percent (the same)

Change relative to 2005: -2 percent

Change relative to 1990: +17 percent

Again not bad — even with the economic recovery, emissions in 2020 will be about two percent less than in 2005. But that’s a long way from the goal of a 17 percent decrease.

Anyone who thought we could meet the 2020 emission target by just going about our business as usual, these projections suggest, is wrong. And if you think meeting our goal is going to be a stretch, check out what’s been going on in China.


* Between 1990 and 2007, U.S. carbon intensity (CO2 per unit of gross domestic product) decreased by 26 percent. In spite of this, emissions rose because of increased energy use.

filed under: carbon dioxide, carbon dioxide emissions, climate change, economy, energy, faculty, global warming
and: , , , , , , , , ,

1 Comment

All comments are moderated and limited to 275 words. Your e-mail address is never displayed. Read our Comment Guidelines for more details.

  1. MattN
    May 14, 2010

    We need CO2 legislation…why? We seem to be doing a fine job of capping it without any required legislation… And don’t think the correlation between economic success and CO2 output is lost on many people. It’s clear they track together…

©2015 Nicholas School of the Environment at Duke University | Box 90328 | Durham, NC 27708
how to contact us > | login to the site > | site disclaimers >

footer nav stuff