The small amount of warming that may set off unstoppable and irreversible changes is termed

A small warming that triggers unstoppable, irreversible change is called a tipping point.

An inflection point describes a change in curvature and is not this climate term.

A turning point is a general phrase, not the specific climate threshold meant here.

Beyond a tipping point the system shifts to a new state that cannot easily be reversed.

Examples include ice-sheet collapse and permafrost thaw crossing critical thresholds.

Scientists warn several climate tipping points may lie close to current warming levels.