Increased precipitation over land due to climate feedback of large-scale bioenergy cultivation

Increased global land precipitation, due to the atmospheric feedbacks of large-scale bioenergy cultivation, may partially compensate the water consumption by such rainfed bioenergy crops at the global scale. Bioenergy with carbon capture and storage (BECCS) is considered to be a key technology for removing carbon dioxide from the atmosphere. However, large-scale bioenergy crop cultivation results in land cover changes and activates biophysical effects on climate, with earth's water recycling altered and energy budget re-adjusted. Here, we use a coupled atmosphere-land model with explicit representations of high-transpiration woody (i.e., eucalypt) and low-transpiration herbaceous (i.e., switchgrass) bioenergy crops to investigate the range of impact of large-scale rainfed bioenergy crop cultivation on the global water cycle and atmospheric water recycling. We find that global land precipitation increases under BECCS scenarios, due to enhanced evapotranspiration and inland moisture advection. Despite enhanced evapotranspiration, soil moisture decreases only slightly, due to increased precipitation and reduced runoff. Our results indicate that, at the global scale, the water consumption by bioenergy crop growth would be partially compensated by atmospheric feedbacks. Thus, to support more effective climate mitigation policies, a more comprehensive assessment, including the biophysical effects of bioenergy cultivation, is highly recommended.

Automated summary

Large-scale cultivation of bioenergy crops can lead to land cover changes and biophysical effects on climate, altering the global water cycle and energy balance. However, it is found that global land precipitation increases under bioenergy scenarios, partially compensating for the water consumption by these crops. Therefore, a more comprehensive assessment is highly recommended for effective climate mitigation policies.