Climate Change: The Next Generation: Andy Ridgwell et al., Tackling Regional Climate Change by Leaf Albedo Bio-geoengineering

Friday, January 16, 2009

Andy Ridgwell et al., Tackling Regional Climate Change by Leaf Albedo Bio-geoengineering

Report

Tackling Regional Climate Change by Leaf Albedo Bio-geoengineering

Andy Ridgwell¹^,^,,Joy S. Singarayer¹,Alistair M. Hetherington²andPaul J. Valdes¹

¹ Bristol Research Initiative for the Dynamic Global Environment, School of Geographical Sciences, University of Bristol, Bristol BS81SS, UK
² School of Biological Sciences, University of Bristol, Bristol BS81UG, UK

Corresponding author

Summary

The likelihood that continuing greenhouse-gas emissions will lead to an unmanageable degree of climate change [1] has stimulated the search for planetary-scale technological solutions for reducing global warming [2] (geoengineering), typically characterized by the necessity for costly new infrastructures and industries [3]. 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 [4,5] because of differences in their albedo (solar reflectivity) compared to soils and to natural vegetation [6]. 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 1C 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[7]. 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.