School of Environment, Geography, and Sustainability, Western Michigan University, 3503 Wood Hall, 1903 W Michigan Ave, Kalamazoo, MI, 49008-5424, USA.
State Key Laboratory of Pollution Control & Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, PR China.
J Environ Manage. 2023 Dec 1;347:119162. doi: 10.1016/j.jenvman.2023.119162. Epub 2023 Sep 30.
Significant shock of climate change on crop yield will challenge the performance of bio-crop on substituting fossil energy to mitigate climate change. Taking cassava-to-ethanol system in Guangxi Province of South China as an example, we coupled a random forest (RF) model with 10 Global climate models (GCMs) outputs to predict the future cassava yields. Subsequently, the net energy value (NEV) and greenhouse gas (GHG) emissions of the cassava-to-ethanol system across varied topographies are assessed using a life cycle analysis. We demonstrate that the abrupt increases in temperatures are the primary contributors to declining yields. Notably, cassava yields in hilly regions decline more than those in plains and display greater variability among concentration pathway scenarios over time. Future NEV and GHG performance of cassava-to-ethanol will undergo significant decreases over time, especially within the high concentration pathway scenario (NEV decrease 28%, GHG increase 3.4% from 2006 to 2100). The performance reductions in hilly area are exacerbated by more harvest loss and labor and material inputs during the "field-to-wheel", negating its energy advantage over fossil fuels. Therefore, adopting a lower concentration pathway and favoring plantation in plains could maintain cassava-to-ethanol as a viable climate mitigation strategy. Our research also advances the methodological approach to climate change adaptation within the domain of life cycle assessment.
气候变化对作物产量的巨大冲击将挑战生物作物替代化石能源以缓解气候变化的表现。以中国南方广西的木薯制乙醇系统为例，我们将随机森林（RF）模型与 10 个全球气候模型（GCM）输出结果相结合，预测未来的木薯产量。随后，我们利用生命周期分析评估了不同地形条件下木薯制乙醇系统的净能源值（NEV）和温室气体（GHG）排放。研究表明，温度的突然升高是导致产量下降的主要因素。值得注意的是，丘陵地区的木薯产量下降幅度超过平原地区，且随着时间的推移，在不同浓度路径情景下的产量变化更为显著。未来木薯制乙醇的 NEV 和 GHG 性能将随着时间的推移而显著下降，尤其是在高浓度路径情景下（2006 年至 2100 年，NEV 下降 28%，GHG 增加 3.4%）。丘陵地区由于“从田间到车轮”过程中收获损失、劳动力和材料投入增加，导致其性能下降更为严重，从而抵消了其相对于化石燃料的能源优势。因此，采用较低的浓度路径并优先在平原种植木薯，可能有助于将木薯制乙醇作为一种可行的气候缓解策略。我们的研究还推进了生命周期评估领域内适应气候变化的方法学方法。
