Carbon sequestration — the permanent removal of carbon from the atmosphere — is driven by Net Primary Productivity(NPP) for any given area of land. What humans do with the vegetation has a lot to do with how much is actually sequestered. Rates at which carbon is permanently tied up in vegetation and soils can vary from about 15% to about 50%. For example, most agricultural production is almost immediately recycled through animals and humans, which results in essentially no sequestration.
Sequestration rates have been estimated by both models and field measurements. The modeling and field work examined by Versar, from which this indicator is drawn, yielded very close to the same estimates for Maryland sequestration rates: about 24% of NPP for forests and 50% for wetlands.
Versar estimated that optimal implementation of a variety of measures to improve sequestration rates—heavily emphasizing protection and management of forests and wetlands for sequestration values and the conversion of underutilized farm land to wetlands and forest—could increase these rates as much as 70% to offset carbon dioxide emissions from power plants and other burning of fossil fuels.