The American Carbon Registry (ACR), a nonprofit enterprise of Winrock International, announced approval of a new carbon offset methodology to scientifically quantify greenhouse gas (GHG) emissions reductions from the restoration of California deltaic and coastal wetlands. The methodology was developed by a high-profile group of partners — the Sacramento-San Joaquin Delta Conservancy as lead agency and HydroFocus as lead author with technical support from the University of California at Berkeley and Tierra Resources. Funding for the methodology was provided by the Sacramento Municipal Utility District (SMUD), the California Coastal Conservancy, the Metropolitan Water District and California Department of Water Resources (DWR).
The new ACR methodology combines California data and restoration techniques to create a rigorous scientific framework for carbon offset project development. Opportunities are abundant to enhance current land-use practices by restoring wetlands or converting to rice cultivation in the Sacramento-San Joaquin Delta, Suisun Marsh, and California coastal areas. Carbon offsets generated by the projects can be sold to corporations to meet their voluntary emissions-reduction goals. Additional sources of offsets are also being considered by California regulators for eligibility in the state’s Cap-and-Trade Program, under which power plants and oil refineries are mandated to reduce or offset their emissions.
In the Bay-Delta Area, more than 90 percent of historic tidal wetlands disappeared in the last 150 years. Over 2.5 billion cubic meters of organic soils have disappeared since delta islands were first diked and drained for agriculture in the late 1800s, resulting in land subsidence up to 25 feet below sea level. Drained and cultivated organic soils continue to oxidize, subside and emit an estimated 1.5 to 2 million metric tons of CO2-equivalent annually — equal to annual emissions from over 300,000 passenger vehicles.