1.5°C pathway

A pathway of emissions of greenhouse gasses and other climate forcers that provides an approximately one-in-two to two-in-three chance, given current knowledge of the climate response, of global warming either remaining below 1.5°C or returning to 1.5°C by around 2100 following an overshoot. See also Temperature overshoot.

1.5ºC aligned

Target is aligned with scenarios that yield a long-term warming outcome of <1.5C with some probability (e.g. 50%, 66%) and some amount of overshoot (no/low), both of which should be explicitly specified.