Management opportunities for enhancing terrestrial CO2 sinks

Authors: POST, WILFRED - Oak Ridge National Laboratory; IZAURRALDE, R - Pacific Northwest National Laboratory; WEST, TRISTRAM - Pacific Northwest National Laboratory; Liebig, Mark; KING, ANTHONY - Oak Ridge National Laboratory

Submitted to: Frontiers in Ecology and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2012
Publication Date: 12/1/2012
Publication URL: http://handle.nal.usda.gov/10113/56380
Citation: Post, W.M., Izaurralde, R.C., West, T.O., Liebig, M.A., King, A.W. 2012. Management opportunities to enhance terrestrial CO2 sinks. Frontiers in Ecology and the Environment. 10(10):554-561. DOI:10.1890/120065.

Interpretive Summary: The biogeochemical potential for mitigating increasing atmospheric carbon dioxide concentration using terrestrial biological carbon (C) sequestration is significant. We estimate the amount of C being sequestered from natural processes at the global, North America and national U.S. scale. The potential of deliberate human action to augment these natural sinks through forestry, biomass fuels, and agriculture is presented and quantified where possible. For some of these activities there is a large potential that can be realized with considerable management and land-use change. For some (e.g., reduced tillage, improved silviculture, woody bioenergy crops) implementation of these changes is already underway because of their economic benefits and co-benefits of additional ecosystem services. Others (e.g., biochar and cellulosic bioenergy crops) require additional research and evaluation of total greenhouse gas impacts to determine if widespread implementation is warranted. Collectively, there is no terrestrial biological management that will solve the carbon dioxide problem, singly or in aggregate. A diversity of current and potential management approaches have significant C sequestration potential, but also have considerable ecosystem benefits beyond C management. Such practices merit aggressive pursuit.

Technical Abstract: To address climate change and the implications of a global mean temperature increase of more than two degrees Celsius over current levels will require terrestrial carbon (C) management along with reductions in fossil fuel emissions. To achieve all or part of the global terrestrial C sequestration potential requires managing, in a concerted way, vast tracts of lands and implementing novel C sequestration methods. Using published data, we estimate the amount of C sequestered through forestry, biofeedstock production, and agriculture at different spatial scales. Forestry activities (e.g., afforestation, reforestation, deforestation avoidance, biomass energy, wood products management, and improved forest management) were found to potentially increase C sequestration in the U.S. by 370 to 740 Tg CO2-equivalent per year. The largest potential for soil C sequestration with agriculture was with no-till, averaging 1.22 t CO2-equivalent per hectare per year (range = -0.24 to 3.22 t CO2-equivalent per hectare per year). Changes in land management for the purposes of C sequestration can increase or decrease greenhouse gas (GHG) emissions. Total net GHG emissions must be considered using the widest applicable system boundaries of the sequestration activities to estimate net impact on the atmosphere. Collectively, there is no terrestrial biological management that will solve the CO2 problem, singly or in aggregate. A diversity of current and potential management approaches have significant C sequestration potential, but also have considerable ecosystem benefits beyond C management. Such practices merit aggressive pursuit.