The passage of AB 32 in 2006 initiated the need for city planners in California to consider the quantification of greenhouse gas emissions at the community level in order to develop policies and programs to reduce emissions in the future. Although local jurisdictions are not required to quantify and report emissions at this time, the AB 32 Climate Change Scoping Plan recommended a reduction goal for local governments of 15 percent below today’s levels by 2020 to ensure consistent reduction goals at the state and local levels. ICLEI-Local Governments for Sustainability initiated the Cities for Climate Protection (CCP) campaign in 1993, which provides a framework for local governments to develop a baseline emissions inventory and identify reduction measures as part of a climate action plan. This inventory is developed under the framework of the CCP campaign. A review of the current practice of local greenhouse gas emissions inventories in California identified significant consistencies across jurisdictions in the overall framework of community and municipal emissions inventories– due largely to the framework provided by the CCP campaign. However, data sources used and methods of measurement vary greatly among local inventories, which limit the ability to compare results. This highlights the need for a standard reporting protocol for community inventories. This baseline emissions inventory document provides the technical information necessary for the city to set reduction goals and facilitates the development of the climate action plan outlining policies and programs that when implemented would reach those goals.

The California Global Warming Solutions Act, also known as Assembly Bill 32 (AB 32), was passed in 2006 to reduce California emissions to 1990 levels by 2020. Senate Bill 375 (SB 375) was passed in 2008 to support AB 32's emission goals. SB 375 aims to reduce emissions from transportation and land use by assigning regional per capita emission targets for 2020 and 2035. Through a series of four case studies of San Diego, San Francisco, Fresno, and Berkeley, this thesis investigates the impacts of SB 375. Each region is required to combine housing and regional transit plans in the hopes of promoting future sustainable growth. By compacting development SB 375 hopes to reduce sprawl and per capita emissions over time by greatly decreasing vehicular miles traveled.

This study determined the state of the practice and emerging trends in developing greenhouse gas (GHG) thresholds of significance for use under the California Environmental Policy Act (CEQA). To describe the adopted, proposed or considered approaches for developing thresholds of significance by air districts and the thought processes behind these decisions, information was obtained through surveys and phone interviews from twelve employees of air districts in California, State agencies, and consultants that are considered experts on this issue. The results of this study include a comparison matrix of the approaches of the three air districts that have adopted or proposed GHG thresholds of significance, and identification of the common themes from air districts’ responses that do not have adopted or proposed thresholds. While the development of GHG thresholds of significance is an evolving practice, emerging trends in this practice were identified. These trends include providing flexibility in options, an emphasis on programmatic approaches and a preference of including bright-line thresholds and efficiency thresholds. Furthermore, this paper concludes that while the three air districts that have proposed or adopted thresholds have laid the groundwork for other districts, some of the approaches or the thresholds themselves may not be easily transferable to other districts based on regional differences. This research provides insight into how GHG emissions might be addressed in CEQA documents throughout the State.