Environmental Defense Fund (EDF), in partnership with the California Rice Commission, Applied Geosolutions, LLC, and TerraGlobal Capital, LLC, have developed a-first-in-kind methodology to quantify greenhouse gas (GHG) reductions from rice production in California.
The methodology, drafted by TerraGlobal Capital, LLC, is a framework for developing offset projects using specific practices in order to sell credits on voluntary and compliance GHG markets. This is an exciting step forward in reducing emissions from agriculture and the California rice industry is one of the first to lead the way.
"The California Rice Commission hopes to demonstrate how our rice growers can assist in addressing the state’s climate change program goals by voluntarily generating offsets and making them available to other affected industries in California," said Paul Buttner, Manager of Environmental Affairs at the California Rice Commission.
Modeling Rice Emissions
Different environmental factors affect rice GHG emissions, preventing a one-size-fits-all solution. A process model like DeNitrification-DeComposition (DNDC) can more accurately predict GHG emissions when given specific parameters, such as soil type, temperature and water regime. Applied Geosolutions, LLC calibrated and validated the DNDC model using field measurements and was able to identify management practices that reduce GHG emissions without affecting yields and to assess mitigation potential in California.
Changing water management, such as reduced flooding and altered drainage timing, provides the largest mitigation opportunity to reduce methane emissions. Water cuts off the oxygen supply from the atmosphere to the soil that results in anaerobic fermentation. Methane, a GHG with a global warming potential 20 times that of carbon dioxide, is a byproduct of anaerobic fermentation.
As a result of an economic feasibility analysis by UC Davis, GHG reduction practices in California were narrowed down to reduced winter flooding, straw baling after harvest, and dry-seeding (as opposed to seeding while flooded), and these three practices are included in the methodology.
Growers who implement one or more of these practices and produce emissions reductions based on DNDC modeling will be eligible to sell offset credits on carbon markets. As a result, growers create an additional revenue source while providing GHG offset credits that are real, permanent, additional, and verifiable.
"The methodology is a first step towards achieving the global mitigation potential for rice," said Belinda Morris, EDF’s Working Lands Regional Director. "In the future, expanding the methodology to include other practices and other geographies could provide incentives for substantial GHG emissions reductions from rice production."
Rice is grown on approximately 346 million acres worldwide, and 90 percent of rice land is flooded for at least part of the season. The International Panel on Climate Change (IPCC) estimates that rice production emits between 31-112 million metric tons of methane per year. Some academic studies have suggested the potential reductions from practices, such as mid-season drainage, in other parts of the world (it is not viable in California) could be in the range of 50 percent. Major emission variables include factors such as production of more than one crop per year and/or farming in certain regions that have higher emissions due to regional soil and weather factors.
While this is an exciting step forward, more work is needed to accurately estimate reductions given economic and technical constraints in various rice-producing regions. For example, in California where only one crop per year is produced, costs of production are high and the soils have relatively low emissions characteristics, it is difficult to envision a program that could achieve much beyond a 10 percent reduction level while other regions might deliver much greater initial reductions.
The methodology has been submitted to two registries, and it is currently open for public review through the Verified Carbon Standard before it is approved and available to generate offset credits. EDF and its partners expect to have protocols approved by the end of 2011. In the meantime, we will continue to find means of reducing transaction costs and further define the market potential of these emission reduction projects.