Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential
Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential
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DOI：
10.1111/gcb.13745
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发表时间：
2017-10-01
影响因子：
11.6
通讯作者：
Gerten, Dieter
中科院分区：
文献类型：
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作者：
Boysen, Lena R.;Lucht, Wolfgang;Gerten, Dieter
大规模的生物质种植园（bp）是减缓气候变化情景中的一个常见因素，因为它们有望带来双重效益：从大气中提取碳并提供可再生能源。然而，它们的陆地二氧化碳去除（tCDR）潜力取决于诸如土地可用性、捕获生物质碳的效率和运行时间等重要因素。土地供应受到以下因素的限制：取决于产量增加和人口增长的未来粮食生产需求、保护自然的要求以及在缓解气候变化方面避免不利的反照率变化的要求。我们将这些因素整合到一个空间明确的生物地球化学模拟框架中，从2020年或2050年开始，持续到2100年，在考虑这些限制后，探索陆地上可用的tCDR机会空间。我们发现，假设未来对自然保护和粮食生产的需求极大地限制了tCDR的潜力。从理论上讲，到2100年，废弃作物和牧场的bp(在80亿人口和产量缺口减少25%的情况下，到2020年类似于1,300 Mha，或者在95亿人口和产量缺口减少50%的情况下，到2050年类似于100 GtC的土地碳储量和生物质收获。然而，如果只有耕地可用，这一潜力将降低80%，如果将反照率降低视为限制土地可用性的因素，这一潜力将降低50%。将天然林、灌木或草地转变为bp可能会产生更大的tCDR潜力。但是要付出高昂的环境代价（例如生物多样性丧失）。最有希望有效实施tCDR的途径似乎是改善有效的碳利用途径、改变饮食趋势或恢复边缘土地以实施tCDR。
Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes. We integrate these factors in one spatially explicit biogeochemical simulation framework to explore the tCDR opportunity space on land available after these constraints are taken into account, starting either in 2020 or 2050, and lasting until 2100. We find that assumed future needs for nature protection and food production strongly limit tCDR potentials. BPs on abandoned crop and pasture areas (similar to 1,300 Mha in scenarios of either 8.0 billion people and yield gap reductions of 25% until 2020 or 9.5 billion people and yield gap reductions of 50% until 2050) could, theoretically, sequester similar to 100 GtC in land carbon stocks and biomass harvest by 2100. However, this potential would be similar to 80% lower if only cropland was available or similar to 50% lower if albedo decreases were considered as a factor restricting land availability. Converting instead natural forest, shrubland or grassland into BPs could result in much larger tCDR potentials. but at high environmental costs (e.g. biodiversity loss). The most promising avenue for effective tCDR seems to be improvement of efficient carbon utilization pathways, changes in dietary trends or the restoration of marginal lands for the implementation of tCDR.