Wetlands in the Sacramento-San Joaquin Delta in northern California have been restored with the aim of removing carbon dioxide from the atmosphere and increasing carbon storage in the soil. It has been found that the newly flooded conditions of the wetlands lead to reduced carbon dioxide emissions from decomposition, and that the intervention helps to sequester carbon, but also leads to the production and increased emission of methane under anaerobic conditions – a biogeochemical trade-off. Delta wetlands are often net sources of greenhouse gases on an annual basis throughout the study period, although they tend to act as sinks during summer periods due to high carbon uptake.