Caldeira Lab Research:Climate Intervention ('Geoengineering')

Impact of geoengineering schemes on the terrestrial biosphere

G. Bala, S. Thompson, P. Duffy, K. Caldeira, & C. Delire

Future implementation of large scale "geoengineering" has often been suggested as a way to combat the impact that unusually high CO2 concentrations will have on our climate. Here, the negative effects that geoengineering could have on the terrestrial biosphere are investigated.

G. Bala, S. Thompson, P. Duffy, K. Caldeira and C. Delire, Impact of geoengineering schemes on the terrestrial biosphere. Geophysical Research Letters, 10.1029/2002GL015911, 2002

CO2, sunlight, and world biomass: The global amount of biomass predicted by the model is shown above for the following situations -  1•CO2 (control run with no change in CO2 or insolation), 2•CO2 (doubled CO2, no reduction in insolation), geoengineered (doubled CO2 plus a reduction in insolation), and solar (reduced insolation but no change in CO2 levels).There was an increase in biomass in the geoengineered and 2•CO2 simulations, implying that rising CO2 levels caused a fertilizing effect and provoked more plant growth globally.


Climate stabilization via ‘‘Geoengineering’’ schemes seek to mitigate climate change due to increased greenhouse gases by compensating reduction in solar radiation incident on earth’s surface. In this paper, we address the impact of these climate stabilization schemes on terrestrial biosphere using equilibrium simulations from a coupled atmosphereterrestrial biosphere model. Climate stabilization would tend to limit changes in vegetation distribution brought on by climate change, but would not prevent CO2 induced changes in Net Primary Productivity (NPP) or biomass; indeed, if CO2 fertilization is significant, then a climate-stabilized world could have higher NPP than our current world. Nevertheless, there are many reasons why geoengineering is not a preferred option for climate stabilization.