Science is today clear, we are facing multiple and interacting global environmental changes that together threaten the stability of the Earth system, and thereby the basis for world development. Six of nine planetary boundaries are today transgressed, providing ample evidence of a coupled global biosphere and climate crisis. The consequences are not only felt as rising frequency and amplitude of extreme events, causing massive social and economic loss and damage. We are rapidly approaching biophysical tipping points which, if crossed, will cause irreversible and self-amplifying impacts. Two key conclusions arise from the latest Earth system science with regards to climate safety. First, that 1.5°C is not a goal or target, it is a biophysical limit. Cross it, and we are likely to trigger multiple tipping points in the Earth system. Second, there is no safe landing for humanity, with regards to a manageable climate, unless we also bend the curves and return back to a safe operating space within Planetary boundaries, for land, water, biogeochemical flows and biodiversity. The Earth system, in a healthy state, has a remarkably high resilience, but we are seeing ample signs of cracks in the buffering capacity of the biosphere, and need to urgently act on all planetary boundary transgressions.

This calls for setting scientific targets for a safe operating space on Earth, to keep the Earth system in a Holocene-like inter-glacial state. The talk also summarizes the multiple crisis we are facing – the climate crisis, the loss of biodiversity, the coronavirus pandemic, the energy crisis etc. A first attempt, based on the work of the Earth Commission, on defining safe and just Earth system boundaries is presented, as well as the Earth for All scenario analyses of pathways towards attaining the SDGs within Planetary Boundaries.

This talk is part of the Uppsala University Celsius-Linnaeus Lectures 2023.