Document: DEN-3-66-10

Simulated climate change impacts on key ecosystem properties of potential compared to current land cover for the conterminous United States.

OJIMA, D.S.* ¹, W.J.PARTON ¹, T.G.F.KITTEL ^1,2, R.KELLY ¹ and M.HARTMAN ¹

Colorado State University, Ft. Collins, CO 80523-1499 ¹
NCAR, Boulder, CO 80537-3000 ²

Abstract:
The VEMAP group has produced a set of transient climate data for the conterminous United States extending from 1895 through 2100. The climate data available past 1993 is derived from the two general circulation models used in the recent National Assessment of Climate Change Impacts. These models are from the Canadian Climate Centre (CCC) and the Hadley Climate Center (HAD). Using the Century ecosystem model with these climate files we simulated changes in net primary production, soil carbon, change in net total system carbon storage, evapotranspiration, and runoff with potential and current land use under a transient elevated CO₂ concentration. The focus of this paper is on the comparative response of agricultural systems, range and croplands, to changes in the transient climate and carbon dioxide trends during the recent decades and into the future. Analysis of plant production, soil carbon, and net system carbon balance indicated that agricultural systems are near neutral to slight sinks for carbon during the last two decades using current land use techniques. Climate change effects due to the 3 to 5 degree centigrade increase during the first 30 years of the GCM scenarios for the central US indicate that reductions in soil carbon occurs, however the inclusion of CO₂ trends tend to offset the decline in system level carbon. The incorporation of better residue management and other adaptive land use management, suggest that higher levels of carbon sequestration is possible in the future.

Keywords: climate change impacts, agroecosystem response to climate change, carbon budget, vegetation ecosytem modelling analysis project

This abstract is being presented at: 4:00 PM in session:
Oral Session #66: Large Scale Climate Change.