Senate Bill 97 directed in 2007 that the California Environmental Quality Act (CEQA) Guidelines be amended by January 1, 2010 to address climate change.  On October 24, 2008 the California Air Resources Board (CARB) released for public review a preliminary draft of Recommended Approaches for Setting Interim Significance Thresholds for Greenhouse Gases (Draft GHG Proposal). 

Under CEQA, projects that are determined to have potentially significant impacts on the environment must undergo considerably more rigorous CEQA review.  Thus, the proposed greenhouse gas (GHG) thresholds of significance will shape the duration and rigor of environmental review for projects of all types.  This is the first chance that Californians have had to comment on thresholds of GHG significance, and this release provides an important opportunity for the public, stakeholders, and local lead agencies to participate in the development of these standards.  

In California most projects that will have a physical change on the environment and are subject to discretionary approval by a public agency must undergo CEQA review.  The level of review required for a project will depend upon whether the project may have a potentially significant impact on the environment.  Since agencies are prohibited from approving a project with significant impacts on the environment if there are feasible mitigation measures or alternatives to reduce or avoid such impacts, the determination of what is significant can be crucial to the ability of a project to proceed in a timely and cost efficient manner, or at all.

Nothing in the Draft GHG Proposal would change the current practice of excluding from CEQA review projects that are either categorically or statutorily exempt, including certain infill residential projects consistent with an area plan, regardless of whether they could have potentially significant GHG emissions. 

The Draft GHG Proposal, sets out some of the difficulties in setting significance thresholds for GHGs.  First, scientific consensus is that GHG emissions must be stabilized soon and the current state goal is to reduce emissions to 1990 levels by 2020 and to 80% below 1990 levels by 2050.  As climate change is the "quintessential cumulative impact," and emissions levels are already above safe levels, it is arguable that any emission of GHGs could be considered significant.  CARB does not recommend this approach, however.  Instead, CARB believes that "non-zero thresholds can be supported by substantial evidence" in light of the fact that some increase in emissions can still be consistent with climate stabilization and current and anticipated regulations in California (including AB 32) will reduce GHG contributions of past and present projects as well as future projects being reviewed under CEQA. 

CARB proposes a sector-specific approach with different types of thresholds (quantitative, qualitative or performance based) for each sector.  The most recent proposed draft includes preliminary threshold concepts for industrial, residential and commercial projects.  CARB is also developing a proposal for thresholds for transportation projects and large dairies.  The California Energy Commission (CEC) is developing an approach for power plants.   

The Draft GHG Proposal for industrial projects proposes a two step process.  First, each project must meet minimum CARB performance standards for construction and transportation emissions.  Secondly, the project, with mitigation, cannot emit more than 7,000 metric tons CO₂ from non-transportation-related GHG sources.  This includes emissions from combustion, process losses, purchased electricity, water usage and wastewater discharge.  If the project does not satisfy these two standards it will be considered to have a significant GHG impact, an EIR must be prepared and all feasible GHG mitigation measures must be implemented. 

For residential and commercial projects, the Draft GHG Proposal identifies two alternate ways in which a project may show that it will not have significant GHG emissions.  First, if the project complies with a previously approved plan that addresses GHG emissions, will not have a cumulatively considerable incremental contribution to impacts identified in the previously approved plan and has a number of specific attributes related to meeting and monitoring GHG targets, then it will not be considered to have significant GHG emissions.  Alternately, if those standards cannot be met, then the project impacts may still be considered insignificant if the project meets the CEC's Tier II Energy Efficiency goal and meets interim CARB performance standards for construction-related emissions, water use, waste, and transportation.  Finally, it must emit no more than a set level of metric tons CO₂ equivalents/yr that has yet to be set by CARB.

Related Articles:

Office of Planning and Research Releases Technical Advisory on CEQA and Climate Change

Draft Scoping Plan Released For Reducing California's Greenhouse Gas Emissions