Agricultural Carbon Sequestration and Emission Reductions: Challenges and Opportunities

Agriculture is responsible for 10-12% of all anthropogenic greenhouse gas (GHG) emissions world wide. A reduction of soil organic carbon emissions through decreased clearing of native vegetation may significantly decrease GHG emissions globally. However, decreasing nitrous oxide emissions from soil may prove more difficult due to the inherent spatial and temporal variability. Opportunities for additional sequestration of soil organic carbon by for example changes in tillage practice exist, but tradeoffs with emissions of nitrous oxide provide a challenge. A watershed view of carbon fluxes across sectors may highlight additional challenges in achieving true emission reductions. Biochar systems can provide greater emission reductions than thermal bioenergy generation if soil benefits are realized. An increasing number of publications highlight reductions of nitrous oxide emissions from soil after biochar additions that should be scrutinized for broader applicability. As for any agricultural carbon sequestration, a broader life cycle view is needed that does not only include agricultural leakages such as indirect land use but looks at all opportunities and challenges across different sectors including energy, water, and recreation.