3.2.13 (HL)—Biosphere integrity planetary boundary

Biosphere integrity links diversity and ecological functions; losing species or populations can weaken regulation of water, nutrients, carbon and energy.

Trace biodiversity loss → reduced functional redundancy → weaker process → feedback. Boundary assessments indicate risk and uncertainty; they do not give one exact global tipping date.

Forest degradation lowers carbon uptake, which can increase warming and further stress the forest—a feedback chain, not proof of a fixed endpoint.

It connects measured loss to ecosystem function and Earth-system consequences, with scale and uncertainty stated.

High risk is not certainty of collapse; distinguish evidence of pressure from prediction of timing.