Inventory Case 16

Responsible Party
Oregon Metro
State Involved
Country Involved
United States
Case Study Type
Inventory Case

Who did it

Oregon Metro, an elected regional government serving more than 1.5 million residents in Clackamas, Multnomah and Washington counties and the 25 cities in the Portland region.

What they did (and when):

Developed a Regional Greehouse Gas Emissions Inventory providing a carbon footprint of individuals and businesses inside the Portland metropolitan region. The Inventory was released in Spring 2010 and is based on 2006 data.

The Inventory shows Materials (Goods and Food) as the largest emissions source with 48% of emissions.


The calculations related to material flows (goods, food and waste) rely on national data with regional adjustments, rather than direct measurements. The Portland metropolitan region’s material consumption, however, is not so different from national averages and the methodology provides a sense of scale with a clear message: consumption matters as much as energy and transportation.

The inventory uses regional data for the consumption of energy and transportation, and makes regional adjustments to national data related to the consumption of materials and food.

The aggregate estimate for the Materials, Goods and Food section did not include international trade due to lack of consistent international production data. However, estimates of our "imported carbon footprint" suggest that the materials emissions could in fact be significantly larger, increasing our national carbon footprint by as much as 20 percent

Why they did it:

As a regional government with responsibility for land use and transportation planning, as well as waste reduction and disposal, Metro is providing leadership in reducing greenhouse gas emissions. Metro has three distinct, but overlapping, roles related to GHG management:

- Legislative obligations

- Planning authority

- Education and data provision

Metro focused on Materials emissions because recent Environmental Protection Agency (EPA) research suggests that those emissions for which we are indirectly responsible– especially those resulting from the production of material goods – comprise a large share of our emissions and are ignored by conventional analyses. The analysis provides a sense of scale with a clear message: consumption matters as much as energy and transportation.

Metro acknowledges that this work builds on recent work by EPA to assemble a new kind of emissions inventory, but it is an evolving process based on the current state of the data and clarity around what type of information is needed. Metro lacked the financial resources to conduct a full-blown, traditional inventory, but wanted its inventory to provide a "sense of scale" of how the region contributes to climate change, in part to make sound decisions regarding where to invest in efforts to reduce emissions.

Results/outcomes/successes/failures/lessons learned:

The relatively small solid waste slice represents the emissions associated with the "end-of-life" disposal of goods and foods. While this emissions source is a small share of total emissions, several things should be noted. First, the success of regional waste reduction programs in keeping this slice small should not be underestimated. Reuse and recycling that diverts materials from disposal and back into use has significant net carbon reduction impacts compared with use of virgin materials – even when transportation impacts of material collection and hauling are counted. Second, the management of the more "upstream" portion of material flows offers many potential GHG-reducing opportunities, such as promoting new green purchasing strategies for businesses and consumers, reducing energy use, and supporting the internalization of the lifecycle carbon costs of goods into their price. While Metro’s role in materials management has traditionally focused on recycling and disposal, the relationships Metro has developed with households and businesses throughout the region may present collaborative opportunities to lower the region’s greenhouse gas emissions from material use.