The greenhouse gas rebound effect from increased energy efficiency across China's staple crops

A thorough examination of the uneven greenhouse gas rebound effect (GHG-RE) from increased energy efficiency at crop-specific level can contribute to GHG emissions reduction. This study first evaluated the embodied energy intensities (EEIs) and embodied GHG intensities (EGHGIs) of China's 32 staple crops from 1997 to 2017. Then, a rebound quantization model was introduced to assess crop-specific GHG-REs. The decisive agronomic inputs for uneven crop-specific GHG-REs were further examined. Finally, a structural path analysis (SPA), combined with a structural path betweenness analysis was adopted to identify the high-priority energy paths involved in producing decisive agronomic inputs, in order to improve energy efficiency while curbing uneven crop-specific GHG-REs. The results show that: (1) grain crops generate larger GHG-REs than cash crops. (2) To prevent rapid growth in GHG-REs, six key and six potentially key staple crops must be paid adequate attention. (3) The energy efficiency of plastic film is the primary contributor to crop-specific GHG-REs; agricultural machinery, synthetic fertilizers, and seeds also play important roles. (4) Emphasis should be placed on energy-saving in the production of decisive agronomic inputs. (5) According to the characteristics of high-priority energy paths, different energy-saving measures can be adopted when producing various decisive agronomic inputs.