Uncertain effectiveness of Miscanthus bioenergy expansion for climate change mitigation explored using land surface, agronomic and integrated assessment models
Uncertain effectiveness of Miscanthus bioenergy expansion for climate change mitigation explored using land surface, agronomic and integrated assessment models
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DOI：
10.1111/gcbb.12982
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发表时间：
2022-06
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通讯作者：
E. Littleton;A. Shepherd;A. Harper;A. Hastings;N. Vaughan;J. Doelman;D. V. van Vuuren;T. Lenton
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作者：
E. Littleton;A. Shepherd;A. Harper;A. Hastings;N. Vaughan;J. Doelman;D. V. van Vuuren;T. Lenton
大规模生物能源在减缓气候变化情景中发挥着关键作用，但其功效尚不确定。本研究旨在通过对比相同缓解情景 (RCP2.6-SSP2) 下三种不同类型模型的结果来量化这种不确定性，与 2°C 温度目标一致。本分析重点关注单一生物能源原料芒草 × giganteus，并对比了综合评估模型 (IMAGE)、针对芒草生物能源量身定制的地表和动态全球植被模型 (JULES) 以及生物能源作物模型 (MiscanFor) 对其产量和环境影响的预测。在当前气候下，JULES、IMAGE 和 MiscanFor 捕捉了欧洲各地芒草产量的观测值和变异性；然而，在热带地区，JULES 和 IMAGE 预测高产，而 MiscanFor 预测广泛的干旱相关顶枯病。 2040-2049 年预测显示，热带地区生物能源种植面积将迅速扩大至 200 Mha 以上。在这十年中，最终的生物量产量范围为 12 (MiscanFor) 至 39 (JULES) Gt 干物质。土壤碳变化范围从 +0.7 Pg C (MiscanFor) 到 -2.8 Pg C (JULES)，具体取决于之前的土地覆盖和土壤碳。2090-99 年预测显示，欧洲预计将采用碳捕获和储存 (BECCS) 大规模生物质能源。这些模型一致认为，全球变暖<2°C将增加高纬度地区的产量，但地中海地区的干旱胁迫可能导致产量低（MiscanFor），并导致土壤碳显着损失（JULES和IMAGE）。这些结果凸显了快速扩大生物质能源供应的不确定性，特别是在干燥的热带气候和未来气候变化可能导致干燥条件的地区。这具有重要的政策意义——因为将升温限制在“远低于 2°C”的常用情景（包括此处探讨的情景）取决于其有效性。
Large‐scale bioenergy plays a key role in climate change mitigation scenarios, but its efficacy is uncertain. This study aims to quantify that uncertainty by contrasting the results of three different types of models under the same mitigation scenario (RCP2.6‐SSP2), consistent with a 2°C temperature target. This analysis focuses on a single bioenergy feedstock, Miscanthus × giganteus, and contrasts projections for its yields and environmental effects from an integrated assessment model (IMAGE), a land surface and dynamic global vegetation model tailored to Miscanthus bioenergy (JULES) and a bioenergy crop model (MiscanFor). Under the present climate, JULES, IMAGE and MiscanFor capture the observed magnitude and variability in Miscanthus yields across Europe; yet in the tropics JULES and IMAGE predict high yields, whereas MiscanFor predicts widespread drought‐related diebacks. 2040–2049 projections show there is a rapid scale up of over 200 Mha bioenergy cropping area in the tropics. Resulting biomass yield ranges from 12 (MiscanFor) to 39 (JULES) Gt dry matter over that decade. Change in soil carbon ranges from +0.7 Pg C (MiscanFor) to −2.8 Pg C (JULES), depending on preceding land cover and soil carbon.2090–99 projections show large‐scale biomass energy with carbon capture and storage (BECCS) is projected in Europe. The models agree that <2°C global warming will increase yields in the higher latitudes, but drought stress in the Mediterranean region could produce low yields (MiscanFor), and significant losses of soil carbon (JULES and IMAGE). These results highlight the uncertainty in rapidly scaling‐up biomass energy supply, especially in dry tropical climates and in regions where future climate change could result in drier conditions. This has important policy implications—because prominently used scenarios to limit warming to ‘well below 2°C’ (including the one explored here) depend upon its effectiveness.