concept

Tipping point

A threshold at which a small, incremental change in a control variable suddenly triggers a large, abrupt, and often irreversible shift to a different state of the system. Below the tipping point, stabilising negative feedbacks hold the system in place; cross it, and self-amplifying positive feedbacks take over and drive the system running away to a new equilibrium - one it will then defend just as stubbornly as the old. Melt bright ice and you expose dark ocean that absorbs more heat and melts more ice; thaw permafrost and you release greenhouse gases that thaw more permafrost. It is why a seemingly durable planetary dial can still break.