Earth beyond six of nine planetary boundaries

TLDR

The study proposes human appropriation of net primary production as a control variable for functional biosphere integrity and uses Earth system modeling of varying transgression levels of climate and land‑system change boundaries to illustrate the systemic impact of anthropogenic pressures. The update shows that six of nine planetary boundaries are transgressed, placing Earth outside the safe operating space; ocean acidification is near breach, aerosol loading exceeds limits, ozone has slightly recovered, and transgression levels have risen for previously overstepped boundaries, underscoring the need to consider anthropogenic impacts systemically.

Abstract

This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.