Some unaddressed issues in proposed cap-and-trade legislation involving agricultural soil carbon sequestration

A number of issues with significant economic and environmental implications are absent from the public discourse or left to implementation in draft legislation addressing climate change and energy security concerns that would create a cap-and-trade (CAT) system. Agricultural soil carbon sequestration (ASCS) is a potential source of emissions offsets in CAT emissions markets that has the potential to lower the societal cost of achieving emissions reductions while building political support for climate change legislation from agricultural interests and farm states. First, because it may take several years after adoption of no-till before the net flux of all GHGs from cropland are a net emissions sink, a minimum contract length will be a minimum requirement for ASCS contracts. Second, once soil carbon levels are saturated, no additional sequestration takes place and thus the soil itself has no capacity to offset additional emissions elsewhere in the economy. This has implications for the flow of payments to farmers over time and the long-term value of temporary sequestration to firms whose emissions are covered by a cap-and-trade market.