Impacts devalue the potential of large-scale terrestrial CO2 removal through biomass plantations
Impacts devalue the potential of large-scale terrestrial CO2 removal through biomass plantations
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DOI：
10.1088/1748-9326/11/9/095010
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发表时间：
2016-09-01
影响因子：
6.7
通讯作者：
Heck, V.
中科院分区：
文献类型：
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作者：
Boysen, L. R.;Lucht, W.;Heck, V.
大规模的生物质种植园（bp）通常被认为是从大气中提取碳，从而降低全球平均温度的可行和安全的气候工程建议。然而，这种陆地二氧化碳去除（tCDR）策略的能力及其对地球系统的更大影响仍有待全面研究——在碳排放增加和气候变化加剧的情况下更是如此。在这里，我们使用一个空间明确的基于过程的生物圈模型，系统地量化了一系列BP情景的潜力和权衡，这些情景代表了关于哪些区域是可转换的不同假设。基于到本世纪末导致全球平均变暖比工业化前水平高2.5摄氏度的中等二氧化碳浓度路径（类似于代表性浓度路径（RCP）的4.5摄氏度），我们假设tCDR将在2038年全球变暖达到1.5摄氏度时实施。我们的研究结果表明，bp只有在像RCP4.5轨迹那样同时减少排放的情况下，才能充分减缓大气中累积碳增加的进程。因此，tCDR平衡额外的、不减的排放，从而导致像RCP8.5这样的“一切照旧”途径的潜力非常有限。此外，在需要的大规模应用中，这些人工林将导致与粮食生产和生物多样性的重大权衡，并对森林面积、生物地球化学循环和生物地球物理特性产生影响。
Large-scale biomass plantations (BPs) are often considered a feasible and safe climate engineering proposal for extracting carbon from the atmosphere and, thereby, reducing global mean temperatures. However, the capacity of such terrestrial carbon dioxide removal (tCDR) strategies and their larger Earth system impacts remain to be comprehensively studied-even more so under higher carbon emissions and progressing climate change. Here, we use a spatially explicit process-based biosphere model to systematically quantify the potentials and trade-offs of a range of BP scenarios dedicated to tCDR, representing different assumptions about which areas are convertible. Based on a moderate CO2 concentration pathway resulting in a global mean warming of 2.5 degrees C above preindustrial level by the end of this century-similar to the Representative Concentration Pathway (RCP) 4.5-we assume tCDR to be implemented when a warming of 1.5 degrees C is reached in year 2038. Our results show that BPs can slow down the progression of increasing cumulative carbon in the atmosphere only sufficiently if emissions are reduced simultaneously like in the underlying RCP4.5 trajectory. The potential of tCDR to balance additional, unabated emissions leading towards a business-as-usual pathway alike RCP8.5 is therefore very limited. Furthermore, in the required large-scale applications, these plantations would induce significant trade-offs with food production and biodiversity and exert impacts on forest extent, biogeochemical cycles and biogeophysical properties.