Quantification of the Impacts of Sustainable Irrigation on Global BECCS Potential

Abstract:

Bioenergy with carbon capture and storage (BECCS) plays a critical role in many stringent climate scenarios to achieve the 2-degree target at the end of this century. Earlier reports showed that unconstrained irrigation can substantially increase the global bioenergy production and therefore reduce land requirement for bioenergy production. However, the extent and consequences of water-resources-constrained irrigation has been poorly explored. Here we find that global BECCS potential only increased by 6% with sustainable irrigation, compared to that with rainfed (0.82 Gt C yr^-1) in 2090. This is considerably lower than the 60% increase with full irrigation. Nonetheless, sustainable irrigation adds little additional water withdrawal (166 km³ yr^-1) to surface water and groundwater compared to that with full irrigation (1393 km³ yr^-1, equivalent to current industry and domestic water withdrawal). Our findings indicate that sustainable irrigation largely limits the BECCS potential but significantly conserves water. Our estimates implied that sustainable BECCS potential is considerably lower than the 2-degree target needed.