The biophysical components of the Earth system—what we call nature for short—are full of surprises, we’ve discovered, and if we push systems too far, they can break and get stuck in an undesired state for humanity. If such tipping points occur in too many systems in too many places—such as the irreversible melting of ice sheets or the release of methane in steppe regions from thawing permafrost—then the combined effect could lead to the crossing of a planetary tipping point that takes us away from the Holocene.
