The risk of climate change has stimulated research into a range of geoengineering ideas (the intentional manipulation of the climate to counteract global warming) to mitigate surface warming. Bio-geoengineering is the suggestion that the reflectance of incoming solar radiation by crops could be increased, thereby providing regional summer-time cooling of up to one degree Celsius over areas where cropland is extensive.
Research into bio-geoengineering has so far employed Earth system models in which crop albedo has been increased by a percentage of previously measured natural variability. In order for bio-geoengineering to be feasible approach to mitigating the effects of global warming it is essential that crop yield is not compromise as increasing pressure from population and climate change.
Bio-geoengineering is inevitably intertwined with food security, as the most important food crops cover the most surface area and are thus the best candidates for increased albedo. Of the three factors influencing crop yield (genotype, environment and management, bio-geoengineering will influence the choice of genotype (high leaf albedo varieties) and the environment.
This work aims to remedy the gaps in knowledge of the natural range in crop reflectance and the impact on yield, with a novel study, working from micro scale wheat leaf reflectance to macro scale climate and yield modelling. By explicitly assessing how wheat leaf reflectance translates into a canopy-scale albedo change, verified data is used to parameterise climate and yield models to explore possible implications.