Executive summary

The report quantifies safe and just Earth-system boundaries (ESBs) across five domains: biosphere, climate, nutrients, freshwater, and aerosols. Seven of eight ESBs transgressed globally, with air pollution exceeded locally. Defines safe and just corridor between ESBs ceiling and minimum access base for food, water, energy, infrastructure.

Billions lack sufficient access; safe ESBs alone insufficient for justice. Earth-system justice minimises harm, ensures minimum needs, redistributes resources. Without transformations, minimum access increases pressures, overshooting climate ESB by 2050.

Part 1 Theoretical framework and methods

Safe ESBs maintain Earth-system stability akin to Holocene conditions. Just ESBs more stringent, prevent significant harm to health, wellbeing, species. Earth-system justice encompasses procedural, substantive elements across interspecies, intergenerational, intragenerational scopes.

Minimum access levels: level 1 for dignity (e.g., toilet access), level 2 for poverty escape. Corridor base from universal minimum access impacts; ceiling from stricter ESBs. Methods integrate biophysical, social quantification in same units.

Part 2 Earth-system boundaries

Eight ESBs defined: biosphere functional integrity, natural ecosystem area; climate; phosphorus, nitrogen cycles; surface, groundwater; aerosols. Transgressions: functional integrity, ecosystem area, climate, phosphorus (140% exceeded), nitrogen, surface/groundwater.

Climate just ESB at 1.0°C warming (vs safe 1.5°C); harms millions below safe threshold. Aerosols need local standards. Minimum access pressures fit most ESBs except climate without redistribution.

By 2050, even equal minimum access overshoots climate ESB absent energy, food transformations.

Part 3 Translation of ESBs across scales

Translates global ESBs to cities, businesses via transcription, allocation, adjustment. Equitable sharing reflects justice; e.g., population-based or needs-adjusted allocation.

Cities, businesses key actors due to impacts, agility. Governance contexts shape approaches; enabling conditions include data, incentives.

Part 4 Transformations

Requires systemic changes: reduce excess consumption, transform economies, technologies, governance. Actors mobilise via coalitions; levers include law (polluter pays, liability), progressive taxation, commons rights.

Health systems integrate equity; urban governance via codes, subsidies cuts sprawl, emissions. Address drivers like fossil fuels; ensure procedural justice for marginalised.