Draft Environmental Impact Report - East Bay Municipal Utility District

Estates Reservoir Replacement Draft Environmental Impact ReportGreenhouse GasesCurrent research suggests that another constituent of aerosols, elemental carbon, mayhave a positive radiative forcing. The primary anthropogenic emission sources ofelemental carbon include diesel exhaust, coal combustion, and biomass burning.Global Warming Potential - GWP is intended as a quantified measure of the globallyaveraged relative radiative forcing impacts of a particular GHG. It is defined as thecumulative radiative forcing both direct and indirect effects integrated over a period of timefrom the emission of a unit mass of gas relative to some reference gas (USEPA 2008).Carbon dioxide (CO 2 ) is the reference gas.The GWP values shown in Table 3.8-3 and Table 3.8-4 allow comparisons of theimpacts of emissions and reductions of different gases.Greenhouse gases with relatively long atmospheric lifetimes (e.g., CO 2 , CH 4 , N 2 O, HFCs,PFCs, and SF 6 ) tend to be evenly distributed throughout the atmosphere; and,consequently, global average concentrations can be determined. However, it is difficultto quantify global radiative forcing impacts for the short-lived gases such as water vapor,carbon monoxide, tropospheric ozone, other ambient air pollutants and troposphericaerosols. GWP values are generally not attributed to these gases that are short-lived andspatially inhomogeneous in the atmosphere. (USEPA 2008)Regulatory BackgroundGlobal Warming Solutions Act (AB 32)The Global Warming Solutions Act of 2006 (AB 32) codifies California’s goal ofreducing statewide emissions of greenhouse gases to 1990 levels by 2020. This reductionwill be accomplished through an enforceable statewide cap on global warming emissionsthat will be phased in starting in 2012 to achieve maximum technologically feasible andcost-effective GHG emission reductions. In order to effectively implement the cap, AB32 directs the Air Resources Board (ARB) to develop appropriate regulations andestablish a mandatory reporting system to track and monitor global warming emissionslevels.While AB 32 does not amend CEQA to require new analytic processes to account for theenvironmental impacts of GHG emissions from project subject to CEQA, it doesacknowledge that such emissions cause significant adverse impacts to the environment.sb09_001.doc 3-8.6 7/22/2009