Table 1 Applied planetary boundary definitions

From: Multiple planetary boundaries preclude biomass crops for carbon capture and storage outside of agricultural areas

Earth system process

Control variable and planetary boundary

Nitrogen flows

(PB-N)

N in runoff to surface water as a proxy for dissolved inorganic N concentrations in surface water (max. 2 mg N l−1 at 0.5° grid cell level)29,122,123

Freshwater change

(PB-W)

River flow reduction as % of potential mean monthly river flow (max. 25%, 40%, and 55% in low-flow, intermediate-flow and high-flow months, respectively; at 0.5° grid cell level considering upstream-downstream effects)29,131

Land system change (PB-L)

Area of forested land as % of potential forest for each biome (min. 85% in tropical and boreal biomes, min. 50% in temperate biomes)30

Biosphere integrity

(PB-B)

Human appropriation of net primary production (NPP) as a percentage of preindustrial NPP (max. 10%, assessed by biomes, n = 61)30,57

  1. Planetary boundary (PB) definitions for nitrogen flows, freshwater change, land system change, and biosphere integrity, including the spatial scale of the assessment for constraining the expansion and management of biomass plantations for bioenergy with carbon capture and storage (BECCS). N nitrogen.
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