Tackling regional climate change by leaf albedo bio-geoengineering
Ridgwell, A., Singarayer, J. S., Hetherington, A. M. and Valdes, P. J. (2009) Tackling regional climate change by leaf albedo bio-geoengineering. Current Biology, 19 (2). pp. 146-150. ISSN 0960-9822
To link to this item DOI: 10.1016/j.cub.2008.12.025
The likelihood that continuing greenhouse-gas emissions will lead to an unmanageable degree of climate change  has stimulated the search for planetary-scale technological solutions for reducing global warming  (“geoengineering”), typically characterized by the necessity for costly new infrastructures and industries . We suggest that the existing global infrastructure associated with arable agriculture can help, given that crop plants exert an important influence over the climatic energy budget 4 and 5 because of differences in their albedo (solar reflectivity) compared to soils and to natural vegetation . Specifically, we propose a “bio-geoengineering” approach to mitigate surface warming, in which crop varieties having specific leaf glossiness and/or canopy morphological traits are specifically chosen to maximize solar reflectivity. We quantify this by modifying the canopy albedo of vegetation in prescribed cropland areas in a global-climate model, and thereby estimate the near-term potential for bio-geoengineering to be a summertime cooling of more than 1°C throughout much of central North America and midlatitude Eurasia, equivalent to seasonally offsetting approximately one-fifth of regional warming due to doubling of atmospheric CO2. Ultimately, genetic modification of plant leaf waxes or canopy structure could achieve greater temperature reductions, although better characterization of existing intraspecies variability is needed first.