Under the Paris Agreement, 195 nations have committed to holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to strive to limit the increase to 1.5 °C (ref. ¹). It is noted that this requires "a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the century"¹. This either calls for zero greenhouse gas (GHG) emissions or a balance between positive and negative emissions (NE)^2,3. Roadmaps and socio-economic scenarios compatible with a 2 °C or 1.5 °C goal depend upon NE via bioenergy with carbon capture and storage (BECCS) to balance remaining GHG emissions^4,5,6,7. However, large-scale deployment of BECCS would imply significant impacts on many Earth system components besides atmospheric CO₂ concentrations^8,9. Here we explore the feasibility of NE via BECCS from dedicated plantations and potential trade-offs with planetary boundaries (PBs)^10,11 for multiple socio-economic pathways. We show that while large-scale BECCS is intended to lower the pressure on the PB for climate change, it would most likely steer the Earth system closer to the PB for freshwater use and lead to further transgression of the PBs for land-system change, biosphere integrity and biogeochemical flows.

根据《巴黎协定》，有195个国家承诺将全球平均温度的上升幅度保持在比工业化前水平高2°C以下，并努力将温度上升幅度限制在1.5°C以内（参考资料¹）。要指出的是，这要求“在本世纪下半叶的人为源排放量与温室气体汇清除量之间保持平衡” ¹。这要么要求零温室气体（GHG）排放，要么要在正排放和负排放（NE）^2,3之间取得平衡。符合2°C或1.5°C目标的路线图和社会经济情景取决于通过生物能源与碳捕获和存储（BECCS）的NE来平衡剩余的温室气体排放^4,5,6,7。然而，BECCS的大规模部署将对大气中的CO ₂浓度^8,9以外的许多地球系统组件产生重大影响。在这里，我们探讨了通过BECCS通过专用种植园进行NE的可行性，以及通过行星边界（PB）^10,11进行多种社会经济途径的潜在权衡。我们表明，尽管大规模的BECCS旨在降低气候变化对PB的压力，但它最有可能使地球系统更接近PB以进行淡水利用，并导致PB进一步侵害土地系统，生物圈完整性和生物地球化学流量。