Since minimum access levels for the poor cannot be met within the ESBs without substantial reallocation of resources, we propose minimum access levels for all people. These levels provide the floor or foundation of a corridor, while the ESBs constitute the ceiling (Fig. 6). If resources, responsibilities and risks are allocated in a just manner (Fig. 1), we consider this a ‘safe and just corridor’.

The black line in Fig. 5 shows that redistribution is not enough; if everyone’s emissions are equalized at escape from poverty levels, then we would still overshoot the climate boundaries

Preserving ecosystem area is sometimes critiqued as ‘fortress conservation’ by environmental justice scholars, limiting access for poor or Indigenous people68. An ecosystem area boundary therefore requires careful consideration and involvement of the local communities, for example by not demanding that intact areas preclude human inhabitation and sustainable use and/or recognizing the role of Indigenous peoples and local communities in already protecting these areas.

Safe and just ESBs aim to stabilize the Earth system, protect species and ecosystems and avoid tipping points, as well as minimize ‘significant harm’ to people while ensuring access to resources for a dignified life and escape from poverty. If justice is not considered, the biophysical limits may not be adequate to protect current generations from significant harm. However, strict biophysical limits, such as reducing emissions or setting aside land for nature, can, for example, reduce access to food and land for vulnerable people, and should be complemented by fair sharing and management of the remaining ecological space on Earth4.

joint knowledge to identify safe and just ESBs