Summary:
The MAPSS team made key contributions to the most detailed assessment of climate change impacts on California to date. The assessment, funded by the California Energy Commission and the Electric Power Research Institute, was designed to help natural resource managers and other policy makers better understand the potential effects of climate change on the state. The MC1 dynamic vegetation model was used to simulate the responses of vegetation distribution, carbon, and fire to two contrasting scenarios of climate change in California. The responses to increasing temperatures under both scenarios were characterized by a shift in dominance from needle-leaved to broad-leaved lifeforms and by increases in vegetation productivity, especially in the relatively cool and mesic regions of the state. The simulated responses to changes in precipitation were complex, involving not only the effect of changes in soil moisture on vegetation productivity, but also changes in tree-grass competition mediated by fire. Total annual fire area was greater than the simulated historical mean by the end of this century under both scenarios. The year-to-year variability in area burned was greatest under the wetter scenario. Relatively low levels of area burned during wet years resulted in greater biomass buildup, thus pre-conditioning the system for high levels of area burned during the less frequent dry years. Total ecosystem carbon increased under both climate scenarios, but the increases in both tree and grass carbon under the wetter and warmer climate scenario were in contrast to the decreased tree and increased grass carbon under the drier and cooler scenario. The state of California is using these results to help frame a new round of research and policy investigations into integrated impacts and responses to climate change throughout the state.
Partners: Oregon State University, California Energy Commission, Electric Power Research Institute, Stratus Consulting Inc., and Yale University.
USFS: Ed DePuit Program Manager, ejdepuit@fs.fed.us; Ron Neilson, MAPSS Team Leader, rneilson@fs.fed.us, (541) 750-7303.
Publication: Lenihan et al. 2003
Summary:
The MAPSS team is producing 6-month fire risk forecasts that will allow agencies to better anticipate firefighting needs, thus increasing fire preparedness. Actual weather observations since 1895 to the most recent month have been gridded over the conterminous U.S. for use by a dynamic general vegetation and fire model. Three different future weather scenarios for the next six months have been appended to the observed weather timeseries for forecasts of possible fire risks over the U.S. The model has demonstrated good skill in simulating the spatial and temporal distributions of observed fire activity in the United States over the last several years.
Summary:
A consortium of American, Canadian and British scientists is producing new assessments of the potential impacts of global warming on North American ecosystems. The project is an intercomparison of Dynamic Vegetation Models (DGVM) under different future climate scenarios. The models will simulate a time series of past, observed climate and then shift to future scenarios. Products will include validation of the models abilities to simulate current vegetation distribution and function, including fire disturbance and scenarios of changes in these ecosystem characteristics under future climates. The project is being staged to contribute products to the next IPCC assessment of the potential impacts of climate change.
Partners: Oregon State University, Waterloo University (Canada), Canadian Forest service, Sheffield University (UK)
USFS: Ed DePuit Program Manager, ejdepuit@fs.fed.us; Ron Neilson, MAPSS Team Leader, rneilson@fs.fed.us, (541) 750-7303).
Summary:
The model MC1 was run in Alaska under historical conditions (1922-1996) and future (1997-2100) climate change scenarios (HADCM2SUL and CGCM1). Projections show that by the end of the 21st century, 75 to 90% of the area simulated as tundra in 1922 is replaced by boreal and temperate forest. From 1922 to 1996, simulation results show a loss of about 9g C m-2 y-1 from fire emissions and 360,000 ha burned each year. During the same period, 61% of the C gained (1.7Pg) is lost to fires. Under future climate change scenarios, fire emissions increase to 11-12 g C m-2 and the area burned increases to 411-481,000 ha y-1. Despite increases in fire losses, the model simulates an increase in C gains during the 21st century until its last decade when, under both scenarios, Alaska becomes a net C source.
Partners: Oregon State University, VEMAP Data group from the National Center for Atmospheric Research (NCAR) headed by Dr. Tim Kittel.
USFS: Ed DePuit Program Manager, ejdepuit@fs.fed.us; Ron Neilson, MAPSS Team Leader, rneilson@fs.fed.us, (541) 750-7303).
Publication: Manuscript (Bachelet et al.) submitted to Can. J. For. Res. (Oct. 2004)