题名：Delayed use of bioenergy crops might  threaten climate and food security

来源：Nature

发表年代：2022年

作者：Siqing Xu, Rong Wang*, Thomas Gasser, Philippe Ciais, Josep Peñuelas,  Yves Balkanski, Olivier Boucher, Ivan A. Janssens, Jordi Sardans, James H. Clark,  Junji Cao, Xiaofan Xing, Jianmin Chen, Lin Wang, Xu Tang, Renhe Zhang

Abstract  The potential of mitigation actions to limit global warming within 2 °C (ref. 1 ) might  rely on the abundant supply of biomass for large-scale bioenergy with carbon  capture and storage (BECCS) that is assumed to scale up markedly in the future.  However, the detrimental efects of climate change on crop yields may reduce the  capacity of BECCS and threaten food security, thus creating an unrecognized  positive feedback loop on global warming. We quantifed the strength of this  feedback by implementing the responses of crop yields to increases in growingseason temperature, atmospheric CO2 concentration and intensity of nitrogen (N)  fertilization in a compact Earth system model9 . Exceeding a threshold of climate  change would cause transformative changes in social–ecological systems by  jeopardizing climate stability and threatening food security. If global mitigation  alongside large-scale BECCS is delayed to 2060 when global warming exceeds about  2.5 °C, then the yields of agricultural residues for BECCS would be too low to meet  the Paris goal of 2 °C by 2200. This risk of failure is amplifed by the sustained demand  for food, leading to an expansion of cropland or intensifcation of N fertilization to  compensate for climate-induced yield losses. Our fndings thereby reinforce the  urgency of early mitigation, preferably by 2040, to avoid irreversible climate change  and serious food crises unless other negative-emission technologies become  available in the near future to compensate for the reduced capacity of BECCS.

Delayed use of bioenergy crops might  threaten climate and food security.pdf