【美国生态系统碳储库与固碳潜力】Zhengxi Tan^a1 Shuguang Liu^b1 Terry L. Sohl^b Yiping Wu^a and Claudia J. Young^c. Ecosystem carbon stocks and sequestration potential of federal lands across the conterminous United States. PNAS 2015 112(41): 12723–12728

Abstract

Federal lands across the conterminous United States (CONUS) account for 23.5% of the CONUS terrestrial area but have received no systematic studies on their ecosystem carbon (C) dynamics and contribution to the national C budgets. The methodology for US Congress-mandated national biological C sequestration potential assessment was used to evaluate ecosystem C dynamics in CONUS federal lands at present and in the future under three Intergovernmental Panel on Climate Change Special Report on Emission Scenarios (IPCC SRES) A1B A2 and B1. The total ecosystem C stock was estimated as 11613 Tg C in 2005 and projected to be 13965 Tg C in 2050 an average increase of 19.4% from the baseline. The projected annual C sequestration rate (in kilograms of carbon per hectare per year) from 2006 to 2050 would be sinks of 620 and 228 for forests and grasslands respectively and C sources of 13 for shrublands. The federal lands’ contribution to the national ecosystem C budget could decrease from 23.3% in 2005 to 20.8% in 2050. The C sequestration potential in the future depends not only on the footprint of individual ecosystems but also on each federal agency’s land use and management. The results presented here update our current knowledge about the baseline ecosystem C stock and sequestration potential of federal lands which would be useful for federal agencies to decide management practices to achieve the national greenhouse gas (GHG) mitigation goal.