Estimating Consumption Related Emissions

Inventorying greenhouse gas emissions according to where goods and services are consumed, rather than produced, illustrates the powerful link between consumption and climate change.

Viewing carbon emissions through a consumption lens provides useful insights to inform a local sustainable consumption strategy. Consumption-Based Emissions Inventory (CBEI) is one tool gaining traction among local, regional and state governments such as San Francisco CA, Portland OR, Eugene OR, King County WA, and the states of California and Oregon. See the CBEI Guidebook for a detailed review of this method for measuring the carbon footprint of consumption.

CBEI reflects a comprehensive approach to estimating municipal consumption-based emissions by accounting for emissions associated with local consumption of goods and services, regardless of where they were produced.  Emissions tied to goods produced locally for export are typically excluded.

This approach encompasses the full lifecycle emissions of goods and services, including those from production, pre-purchase transportation, wholesale and retail, use, and post-consumer disposal. The methodology is based on spending by households and government entities, and certain types of purchases made by businesses (e.g., capital and inventory formation).

Estimating a community’s emissions in this way reveals very useful information about the impact of local consumption patterns:

  • What we buy matters. In the Portland analysis, consumption of food, goods and services accounted for 53% of all consumption based emissions. The remainder comes from home energy use and transportation fuels. Households contribute the majority of emissions.
  • Lifecycle stage is important. Portland reported that on average, 56% of emissions were from the production of goods and services while 31% come from the use phase (e.g. appliances, lighting, personal vehicles).
  • Goods vs. services. Goods have greater carbon intensity than services but within both, carbon intensity can vary greatly. Certain materials (meat, for example) and services (airplane travel, garbage collection) have emissions intensities many times higher than the average.
  • Bigger footprint. Total consumption-based emissions are typically higher with CBEI than traditional inventory methods.

Value Proposition for Sustainable Consumption

Estimating consumption-based emissions helps cities illustrate the strong link between consumption and climate change and provides them with a platform for addressing consumption in climate action planning efforts. Specifically, this type of analysis provides a method for designing local programs that reduce emissions through:

  • Targeting carbon-intensive consumption categories
  • Targeting lifecycle phases (e.g. production, use) with the highest emissions
  • Supporting shifts in consumption to those activities with lower emissions

Potential City Roles

  • Promote—use results to highlight the relationship between sustainable consumption and climate change.
  • Fund—provide grants and other financial support for programs and projects that target carbon-intensive consumption.
  • Educate/outreach—provide resources and information through outreach campaigns that help the public shift consumption activities that have the highest impacts.
  • Develop programs/services—incubate climate action programs in partnership with other organizations based on sustainable consumption assessments.
  • Demonstrate/Own—implement internal climate action strategies within municipal government that reflect the consumption-based carbon emissions analysis.

Implementation Challenges and Potential Solutions

Most municipal consumption-based emissions inventories rely on estimates of consumption, and these estimates are imprecise. They don't typically record actual changes resulting from municipal sustainable consumption initiatives. So while consumption-based inventories are helpful at communicating how consumers contribute to GHG emissions and the global impact of consumption, they aren't particularly accurate at tracking real change over time. See the CBEI Guidebook for a more complete discussion.

Cities wishing to develop their own CBEI may find it difficult to obtain useful data and access to the necessary expertise. This is an area of innovation, and is not yet common practice but there is a growing body of resources to support cities in conducting CBEI. ICLEI now includes guidance on consumption-based accounting in its U.S. protocol for community inventories, and new methodologies are emerging, such as the tools from the CoolClimate Network, that may provide a feasible alternative for cities. See the CBEI Guidebook for tools and resources to meet your needs and budget.


Most entities that have conducted CBEI have done so in conjunction with a more traditional sector-based (also referred to as “in-boundary” or “territorial”) inventory. They each represent a different view on emissions and, taken together, provide a more complete and accurate picture of the climate impact of local economic activity. The CBEI Guidebook describes in greater detail the benefits of using these two methodologies in tandem to inform local climate action efforts.

Further Resources