Energy Policy Initiatives Center

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EPIC Releases First-Ever Greenhouse Gas Inventory for the San Diego Region

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The University of San Diego School of Law’s Energy Policy Initiatives Center Releases First-Ever Greenhouse Gas Inventory Report for San Diego County

Report details regional emissions and potential strategies to reduce emissions to meet legislated reduction targets

The Energy Policy Initiatives Center (EPIC), a research center at the University of San Diego (USD) School of Law, today released a report that provides a detailed accounting of greenhouse gas emissions for San Diego County. The report also identifies 21 strategies for the region to reduce its emissions to 1990 levels by 2020, the statutory limits in the California Global Warming Solutions Act of 2006.

“The San Diego Foundation provided seed funding and partnered with USD to support the development of the regional greenhouse gas emissions inventory, the first report of its kind in San Diego and perhaps California,” says EPIC Director Scott Anders. “We undertook this task to provide fact-based information about the sources of greenhouse emissions in our region in order to help local and regional decision-makers prioritize actions as they consider ways to reduce emissions.” 

The project, a joint effort between EPIC and the Department of Chemistry and Biochemistry at USD, calculated historical greenhouse gas emissions from 1990 to 2006 using the best available data, and then estimated future emissions to 2020 for San Diego County. Using emissions reduction targets codified in California’s Global Warming Solutions Act of 2006 (AB 32) as a guide, the study also sought to
establish emissions reductions targets for the region. Although AB 32 does not require individual sectors or jurisdictions (e.g., cities and counties) to reduce emissions by a specific amount, the study
calculated the theoretical emissions reductions necessary in each emissions category (e.g., transportation, electricity, etc.) for San Diego County to reduce emissions to 1990 levels by 2020. Finally, the study sought to identify and quantify potential emissions reduction strategies to determine the feasibility of reducing emissions to 1990 levels by 2020.

“We show that through the combination of 21 strategies from all sectors of the economy, the region could reduce greenhouse gas emissions to 1990 levels by 2020. No one sector can do it alone and
contributions from every sector—however small—will be necessary to meet these level,” said Anders. “The largest emissions reductions likely will come from car and truck efficiency measures and increasing the supply of renewable energy to serve regional electricity needs.”

Key findings of the study include the following.

•    San Diego County emitted 34 million metric tons of carbon dioxide equivalent (MMT CO2E) in 2006 – an 18 percent increase over 1990 levels, commensurate with population growth during the same period.

•    In 2006, per-capita emissions for San Diego County were 12 metric tons CO2E, which is slightly lower than California as a whole (13) and significantly lower than the US levels (24).

•    In 2006, emissions from cars and light duty trucks represented 46 percent of total greenhouse
gas emissions in San Diego County.

•    By 2020, under a business-as-usual scenario, regional greenhouse gas emissions are expected to be 43 MMT CO2E, an increase of 9 MMT CO2E (26 percent) over 2006 levels and 14 MMT CO2E (48 percent) over 1990 levels.

•    To meet AB 32 emission reduction targets (1990 levels by 2020), San Diego County would have to reduce emissions by 14 MMT CO2E (33 percent) below projected business-as-usual levels in 2020.

•    Nearly 60 percent of total regional emissions are associated with individuals (e.g., passenger vehicles, light duty trucks, residential electricity and natural gas consumption).

•    San Diego County likely can reduce its greenhouse gas emissions to 1990 levels by 2020 through a combination of reduction strategies from all sectors. This study estimates that through a combination of 21 strategies, the region could reduce its emissions by 15 MMT CO2E by 2020, more than the quantity required to reach 1990 levels.

•    In the scenario above, reductions from the on-road transportation sector (7 MMT CO2E) and the electricity sector (5 MMT CO2E) represent 81 percent of total reductions.

•    Two statewide policies would account for 41 percent of these greenhouse gas emissions reductions. Implementing the Pavely (AB 1493) vehicle emissions standards by 2020 would reduce emissions by just over 3 MMT CO2E, 21 percent of total reductions, and implementing a 33 percent renewable portfolio standard by 2020 would reduce emissions by 3 MMT CO2E, 19 percent of total reductions.

•   The 2003 wildfires were the largest source of GHG emissions (nearly 8 MMT CO2E), more than light-duty trucks, which is typically the single largest source.

The project was made possible with funding from the San Diego Foundation, San Diego Association of Governments, and NRG Energy, Inc.

“The funding of this report is part of a larger effort by the San Diego Foundation to support local research on climate change and regional efforts to reduce emissions and decrease our vulnerability
to climate change impacts,” says Bob Kelly, president and chief operating officer of the San Diego Foundation.

To download copies executive summary and eight supplemental reports, please see the EPIC Web site at


Scott Anders
(619) 260-4589