1.5°C goal
The Paris Agreement aim of pursuing efforts to limit global warming to 1.5°C above pre-industrial levels.
Example
Scenario studies compare pathways that hold warming near this level with those that exceed it.
The catch
A single year above 1.5°C differs from breaching the goal, which concerns warming averaged over decades.
In more depth
1.5°C goal, explained.
Because warming tracks cumulative CO₂ emissions, the 1.5°C goal implies a remaining carbon budget that shrinks every year the world keeps emitting. Pathways assessed by the IPCC that hold temperatures near this level reach net zero CO₂ around the middle of the century and cut methane deeply as well. That second lever acts fast. UNEP's Global Methane Assessment found that cutting human-caused methane by 45% this decade would avoid nearly 0.3°C of warming by the 2040s.
Warming does not become harmless below the line or hopeless above it. The IPCC finds that risks from heat extremes, sea-level rise and ecosystem loss climb with each increment, so avoiding a fraction of a degree still counts. Scenarios that pass the limit and later return describe a temperature overshoot, and the return leg depends on large-scale carbon dioxide removal.