Climatic impact of carbon sequestration through reforestation

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The Kyoto Protocol allows for emissions of CO2 from fossil fuel use to be offset through the creation of carbon sinks through reforestation. This is allowed because emission followed by prompt absorption of CO2, or no emission and absorption, have identical effects on atmospheric CO2. However, the climatic impacts are not the same because of alterations in the surface properties (namely, the surface albedo or reflectivity) through reforestation. In particular, many C-sink activities likely have a direct warming effect on climate, while removing CO2 from the atmosphere. The impact on CO2 of creating a C sink decreases over time due to interactions with other parts of the carbon cycle, while the radiative effect through alterations in the surface  reflectivity due to reforestation persist as long as the reforestation persists. Canadian policy analysis to date has focused on possible reforestation in Canada and in China (for which Canada might participate and receive some credit). The net climatic impact of reforestation in Canada and in China on climate has not been rigorously assessed, although the potential C sink that could be created has been assessed. The purpose of the proposed research is to provide an assessment of net effects and how they would change over time. The proposed research will consist of (i) adding the capability of radiative transfer calculation to a geographically-specific vegetation/C-storage model that has been used in Canada and in China to assess the potential for C sequestration; (ii) to add an atmosphere column with radiative transfer calculations over top of the vegetation model; (iii) to couple a geographically-distributed implementation of the above models to simple climate and carbon-cycle models so as to assess the interactions of C sequestration with other parts of the carbon cycle; and (iv) to use a state-of-the-art atmospheric general circulation model to assess indirect radiative effects of reforestation through changes in clouds.