Portland on CO2 Claims: Whoops!

The City of Portland, OR released a report in June which claimed that carbon dioxide emissions in Portland and Multnomah County have dropped below 1990 levels, the first time a major U.S. urban area has shown such a decrease. The City trumpted these claims loudly and received a great deal of media attention (see here, for example). But not so fast…our friends at the Cascade Policy Institute investigated the issue and forced the city to admit a fairly large error:

Portland’s Office of Sustainable Development (OSD) has quietly recanted its much-publicized claim that 2004 carbon dioxide emissions in Multnomah County dropped below 1990 levels. In response to data requests from the Cascade Policy Institute, a Portland-based think tank, the OSD admitted that a math error resulted in a 2004 carbon dioxide calculation that was 74,561 tons too low. The re-stated total puts Multnomah County above the 1990 levels by more than 68,000 tons.

Moreover, the Cascade Policy Institute asserts that the methodology used in these calculations was seriously flawed, and may have considerably understated the transportation-related emissions. “The OSD relied primarily on gasoline sales in Multnomah County to estimate local travel levels, even though there are more than 100,000 commuters who work or live outside the county,” said John A. Charles, Jr., President of Cascade. “Since gasoline is frequently cheaper in suburban locations, it’s likely that many motorists have been purchasing their fuel outside the county,” he pointed out.

The City’s letter admitting the error is here, and Cascade’s analysis of the report is here. Given the fanfare around the original story, I wonder how loudly they’ll trumpet this recanting…(crickets…crickets…crickets…)