Institute of Biological and Environmental Sciences, Scottish Food Security Alliance-Crops & ClimateXChange, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UU, UK.
Glob Chang Biol. 2016 Mar;22(3):1315-24. doi: 10.1111/gcb.13178. Epub 2016 Jan 6.
Despite 20 years of effort to curb emissions, greenhouse gas (GHG) emissions grew faster during the 2000s than in the 1990s, which presents a major challenge for meeting the international goal of limiting warming to <2 °C relative to the preindustrial era. Most recent scenarios from integrated assessment models require large-scale deployment of negative emissions technologies (NETs) to reach the 2 °C target. A recent analysis of NETs, including direct air capture, enhanced weathering, bioenergy with carbon capture and storage and afforestation/deforestation, showed that all NETs have significant limits to implementation, including economic cost, energy requirements, land use, and water use. In this paper, I assess the potential for negative emissions from soil carbon sequestration and biochar addition to land, and also the potential global impacts on land use, water, nutrients, albedo, energy and cost. Results indicate that soil carbon sequestration and biochar have useful negative emission potential (each 0.7 GtCeq. yr(-1) ) and that they potentially have lower impact on land, water use, nutrients, albedo, energy requirement and cost, so have fewer disadvantages than many NETs. Limitations of soil carbon sequestration as a NET centre around issues of sink saturation and reversibility. Biochar could be implemented in combination with bioenergy with carbon capture and storage. Current integrated assessment models do not represent soil carbon sequestration or biochar. Given the negative emission potential of SCS and biochar and their potential advantages compared to other NETs, efforts should be made to include these options within IAMs, so that their potential can be explored further in comparison with other NETs for climate stabilization.
尽管已经努力了 20 年以遏制排放，但温室气体（GHG）在 21 世纪 00 年代的排放量增长速度比 90 年代更快，这给实现将变暖限制在工业化前水平以下 2°C 的国际目标带来了重大挑战。综合评估模型的最新情景需要大规模部署负排放技术（NETs）才能实现 2°C 的目标。最近对包括直接空气捕集、增强风化、碳捕获和封存生物能源以及造林/毁林在内的 NETs 的分析表明，所有 NETs 的实施都存在重大限制，包括经济成本、能源需求、土地利用和水利用。在本文中，我评估了土壤碳固存和生物炭添加到土地的负排放潜力，以及对土地利用、水、养分、反照率、能源和成本的潜在全球影响。结果表明，土壤碳固存和生物炭具有有用的负排放潜力（分别为 0.7 GtCeq.yr(-1) )，并且它们对土地、水利用、养分、反照率、能源需求和成本的潜在影响较小，因此与许多 NETs 相比具有较少的缺点。土壤碳固存作为 NET 的局限性在于汇饱和和可逆性问题。生物炭可以与碳捕获和封存的生物能源结合使用。当前的综合评估模型没有代表土壤碳固存或生物炭。鉴于 SCS 和生物炭的负排放潜力及其与其他 NETs 相比的潜在优势，应努力将这些选项纳入 IAMs 中，以便进一步探索它们在气候稳定方面与其他 NETs 的潜力。
