County’s emissions almost at ’90 levels

SUSTAINABLE LIFE • Greenhouse gases decline despite 15 percent increase in population

By Toby Van Fleet

The Portland Tribune, Nov 20, 2007, Updated Oct 30, 2009 (18 Reader comments)

Kyle Green / Tribune File Photo

Oregon is one of the few states in the country where fuel sales have remained flat in recent years. Multnomah County fuel consumption has decreased 13 percent per capita since 1990.

Greenhouse-gas emissions – believed to be a major contributor to climate change – are down to just 0.1 percent above 1990 levels in Multnomah County, according to the city’s Office of Sustainable Development.

That decrease, city officials said, comes despite the area’s 15 percent population growth since 1990.

The report was presented to the Portland City Council and the Multnomah County Board of Commissioners on Nov. 1, less than three weeks before a United Nations panel on climate change released a report saying that reductions in greenhouse gases had to begin immediately to avert a global climate disaster.

U.N. Secretary-General Ban Ki-moon called climate change “the defining challenge of our age.” The report is expected to affect policy decisions worldwide.

Portland’s latest numbers also came on the heels of Seattle’s announcement last month that it has cut emissions 8 percent since 1990.

Portland’s numbers are part of the city and county’s global-warming action plan. OSD Deputy Director Michael Armstrong said the plan is designed to track trends in greenhouse-gas emissions and inform regional policy around energy efficiency, transportation, land-use planning and building practices.

“It’s a plan that identifies policies and programs that will move us in the direction we need to go,” he said.

The plan set a goal for Portland to reduce its emissions to 10 percent below 1990 levels by 2010.

After the presentation of the report, the City Council passed a resolution to move forward on a revised plan, slated for 2008, that would aim to reduce Multnomah County emissions to 80 percent below 1990 levels by 2050. The county board passed its own resolution to work with the city on the plan.

This year, the state of Oregon committed to a reduction goal of 75 percent by 2050. A shorter-term goal on that timeline is to get the state’s emission levels to 10 percent below 1990 levels by 2020.

Carbon measurements differ

The methods that Seattle and Portland use to try to estimate greenhouse-gas emissions differ. But, Armstrong said, the exact numbers are not as important as overall trends.

“We’re interested in a metric that over time gives us a legitimate picture of a trend,” he said.

However, tracking those trends, especially in smaller bubbles like cities and counties, can be tricky.

The city collects available data – primarily for greenhouse gases associated with energy consumption and landfills – and plugs it into software provided by ICLEI-Local Governments for Sustainability, an international association of governments committed to sustainable development.

Some data, like electricity generation, is fairly straightforward, with the number of kilowatt-hours sold in the county translated into metric tons of emissions, principally carbon dioxide.

Nationally, the No. 1 source of carbon dioxide – which represents about 84 percent of the nation’s total greenhouse emissions – is power generation from natural gas and coal, followed closely by petroleum-burning cars and trucks.

In Multnomah County, electricity, natural gas and gasoline together account for nearly 85 percent of the area’s total emissions, according to the OSD.

But tracking emissions from motor vehicles is not an exact science.

The city uses the county’s annual gasoline sales, but the data does not include diesel fuel or airplane traffic.

Diesel data only is available at the state level.

Numbers tracked by the Port of Portland and the Oregon Department of Energy show carbon dioxide emissions at Portland International Airport are down slightly from 466,130 metric tons per year in 1990 to 454,550 in 2005, after a spike to a peak of almost 600,000 metric tons in 1999.

By contrast, Seattle includes both diesel data and air traffic in its emissions reports. And its car-related emissions are based not on fuel sales but on the number of vehicle miles traveled, tracked by the state of Washington. Resulting emissions are figured in an equation using an average fuel efficiency.

County fuel sales drop

Critics of the fuel sales methodology that Portland uses say it gives an incomplete picture, pointing to factors those numbers overlook, like any discrepancy between where the gas is bought and where it is burned, as well as the increase in the number of vehicles registered in Multnomah County and miles traveled per person, which is tracked by the state.

More cars and more miles driven should mean more emissions, critics suggest.

Armstrong admitted that the gas numbers are not perfect, but said better fuel-efficiency has more than compensated for those increases.

Oregon is one of the few states in the country where fuel sales have remained flat in recent years, and gasoline sales in the county, tracked by the Oregon Department of Transportation, have decreased 13 percent per capita since 1990. Officials attribute that plateau in part to more compact land use and public transit in the Portland area, as well as fuel-efficiency.

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