Fig. 5: Impacts on the Earth-system processes and ranking of scenarios by impacts on human health and the Earth system.

a Impacts on Earth-system processes expressed as a percentage of the size of the Safe Operating Space (SOS). The impacts on the following Earth-system processes were assessed: climate change—considering atmospheric CO₂ concentration (CC-CO₂) and energy imbalance (CC-EI) as control variables—, ocean acidification (OA), terrestrial biosphere integrity (TBI), global biogeochemical flows—considering the application rate of intentionally fixed reactive N to the agricultural system (BGC-N) and phosphorus flows from freshwater into the ocean (BGC-P) as control variables—, global freshwater use (FWU), stratospheric ozone depletion (SOD), and global land-system change (LSC). Scenarios 1–16 comprise High-Temperature Liquid Sorbent (HTLS) and Low-Temperature Solid Sorbent (LTSS) Direct Air Carbon Capture and Storage (DACCS)—powered by natural gas with carbon capture and storage (NG+CCS), wind, solar photovoltaic (PV), nuclear, geothermal (GEO), or the global electricity mix deployed in the SSP2-1.9 marker scenario (which limits the increase in radiative forcing to 1.9 W/m² by 2100 and is based on Shared Socioeconomic Pathway 2) without NETs—, the basic Bioenergy with Carbon Capture and Storage (BECCS) scenarios (BECCS0) deploying Miscanthus (MISC) or poplar (POP)—assuming either Soil Carbon Sequestration (SCS) or land-use change (LUC)—, the hybrid BEDACCS configurations integrating BECCS0 and LTSS-DACCS, and the BECCS scenarios where CO₂ is mineralized ex situ (BECCS-EXSITU). The values of empty cells range between 0 and 0.05%. We show qualitatively the current level of the control variables for the Planetary Boundaries (PBs) of the studied Earth-system processes below, according to the PB framework²². b Ranking of scenarios by health impacts and maximum impacts across Earth-system processes relative to the SOS size, scenario 1 is the best.