Project -- VEMAP Phase 2

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NTSG VEMAP Global Project

The Vegetation/Ecosystem Modeling and Analysis Project, VEMAP, is a multi- institutional, international effort whose goal is to evaluate the sensitivity of terrestrial ecosystem and vegetation processes to altered climate forcing and elevated atmospheric CO2.

The project's objectives are:

• Comparison of model output for current conditions
• Intercomparison of the climate and CO2 sensitivity of three biogeochemistry models (plant production and soil biogeochemical process models) and three vegetation lifeform distribution models (biogeography models).
• Linking vegetation distribution and ecosystem physiology models to evaluate the joint response of these processes to altered conditions.

For more detailed VEMAP project information, click here.

The MAPSS biogeography and UKMO climate models show predicted changes in vegetation lifeform (e.g. grasslands to forests; forests to grasslands) between current and altered climate/atmospheric CO2 concentrations.In general, biome redistributions are most prevalent in the eastern half of the United States, where current forested systems are replaced by new mixtures of climate-mediated forest types. In particular, these simulations suggest that forested biomes in the north and southeastern United States will decline to shrublands and savannas, respectively. Additionally, losses of grasslands to woody savannas are predicted for the great plains. The impact of vegetation redistribution on plant productivity and ecosystem biomass as predicted by Biome-BGC is most evident in the midwest and eastern portions of the conterminous United States.

As you can see,maximum productivity shifts in the midwest and eastern regions from the south to the north.

The difference between current and doubled atmospheric CO2 concentrations, combined with altered climate for all VEMAP ecosystem, biogeography, and climate models suggests that a broad envelope exists for potential vegetation lifeform responses to climate change. Changes in total ecosystem biomass are particularly evident as predicted losses in the northeast and along the Rocky Mountains.

It is clear from the VEMAP simulations that changes in atmospheric CO2 concentrations and climate can have dramatic effects on the distribution of forests and grasslands in the conterminous United States. Ecosystem models, such as Biome-BGC, when coupled with biogeography and climate models can therefore provide essential predictive tools to facilitate policy and management decisions in a changing environment.

MAPSS-BGC Model Intercomparison and LAI Validation of MAPSS with BIOME-BGC and OTTER Data

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