UNEP pathway to 1.5°C calls for steep emissions cuts and carbon removal

The world would need to cut greenhouse gas emissions sharply this decade and depend on removing carbon from the atmosphere to follow a pathway back to 1.5°C of warming by the end of the century, the UN Environment Programme says.

In its October 21 release, UNEP describes a conditional modeled pathway in which warming relative to pre-industrial levels peaks near 1.7–1.8°C around mid-century. Under that pathway, the chance of returning to or below 1.5°C by 2100 is about 50%. That figure describes the chance of the later return; it is not the probability attached to the peak range.

The pathway requires global greenhouse gas emissions to fall 18% by 2030 and 45% by 2035, both relative to 2025 levels, UNEP says. If national pledges are fully implemented, the assessed reductions would instead be 5–8% by 2030 and 11–15% by 2035, also relative to 2025. Those are scenario comparisons, not cuts already achieved.

Returning to the lower temperature level in the pathway also depends on removing carbon from the atmosphere and storing it permanently. UNEP says the socioeconomic and technical feasibility of that requirement is uncertain. It also identifies policy successes already in place, while noting that they are concentrated in particular sectors, places and periods and would need broader, sustained implementation.

The dates behind the comparison matter. Carbon Brief’s October 21 explainer says the assessment’s current-policy assumptions use policies implemented by November 2025, while its pledge cutoff is September 1, 2026. Those dates describe the inputs used in the assessment, not a live inventory of everything governments have done or pledged since. Carbon Brief also says provisional figures do not establish the overall direction of global emissions in 2025.

Rowan Finch analysis

The pathway is best read as a set of conditions, not a temperature promise. Its near-term reductions and later reliance on removal and permanent storage belong to the same picture: meeting one requirement cannot simply be assumed from the existence of the other. The comparison with pledges illustrates the difference between a stated commitment, even if fully implemented, and the larger cuts the modeled pathway requires.

The infrastructure question remains open. A scenario can include removal and permanent storage without establishing that the necessary scale is technically or socioeconomically feasible. Likewise, a policy cutoff tells readers which measures went into an assessment; it cannot establish what has happened since. Both details matter when turning a model result into expectations about the real world.

UNEP’s release and Carbon Brief’s independently authored explainer draw on the same assessment, not two independent models. Carbon Brief discloses that its deputy editor and senior policy editor, Simon Evans, observes the report’s steering committee. The full assessment and model were not independently reviewed or rerun for this report.