Climate: four scenarios, from 2.7 °C to 1.9 °C in 2100

The Climate Action Tracker estimates that current policies are associated with warming of 2.7 °C by 2100. Lower scenarios depend on additional commitments and their implementation.

The Climate Action Tracker (CAT) estimates that the climate policies currently in place would lead to global warming of 2.7 °C by 2100, compared with pre-industrial times. Its update, published on 12 November 2026, distinguishes this result from several conditional pathways, which are lower but depend on additional commitments. These figures do not represent four equivalent forecasts: they reflect four different assumptions about what governments will actually do.

The increase from 2.6 °C to 2.7 °C compared with the previous assessment does not mean that the planet has warmed by 0.1 °C in a year. According to the CAT briefing, it is explained mainly by updated historical data and refined projections of existing policies, rather than by major policy changes worldwide.

Four pathways, four assumptions

The CAT compares warming scenarios for 2100. The first, ‘policies and action’, is based on policies currently in place and leads to 2.7 °C. It projects the effects of policies in force, rather than assuming that all announcements will be carried out.

The 2030 and 2035 targets scenario gives 2.6 °C, on the condition that governments meet the targets they have set for those two milestones. On its own, it does not assume that all long-term targets will be met.

A third calculation, ‘pledges and targets’, leads to 2.1 °C. It includes nationally determined contributions (NDCs)—the climate commitments submitted by countries—for 2030 and 2035, as well as submitted and binding long-term targets. This result is 0.1 °C lower than the previous year’s.

Finally, the optimistic scenario reaches 1.9 °C. It assumes the full implementation of all announced climate targets, including carbon neutrality targets, long-term strategies and NDCs. This is the most favourable assumption in the analysis, not a forecast of what will happen automatically.

Assumption assessed by the CAT	Central projection for 2100
Policies and action in place	2.7 °C
2030 and 2035 targets met	2.6 °C
Pledges and targets, including long-term commitments	2.1 °C
Full implementation of all announced climate targets	1.9 °C

These values are the central estimates of the CAT’s projections. They are neither a range of probabilities nor four levels of certainty. The more commitments that have yet to be fulfilled a scenario includes, the more its result depends on their effective implementation.

The gap between a target and an implemented policy

A national announcement can guide decisions, but its mere existence does not reduce emissions. The CAT points out that ambitious targets risk remaining promises if they are not accompanied by credible policies and immediate implementation. This is why the figure associated with policies already in place remains distinct from the one that assumes longer-term commitments are met.

The gap between 2.7 °C and 2.1 °C should therefore not be read as warming that the pledges would guarantee to avert. It reflects two different assumptions about future action. The 2.1 °C scenario requires the relevant targets to be met; the 2.7 °C scenario is based on the policies that the CAT considers to be currently in force.

The network says that aggregate climate action has, for the most part, stagnated for five consecutive years, with progress and setbacks offsetting each other in its overall assessment. This wording describes an overall trend: it does not mean that no policies have advanced, or that all countries have followed the same path. The analysis also notes progress, particularly in the development of renewables in China and India, and setbacks in some countries.

The Paris threshold is measured over time

The Paris Agreement aims to keep global warming well below 2 °C compared with pre-industrial times, while pursuing efforts to limit it to 1.5 °C. This benchmark compares global averages with the period 1850–1900, not the temperature of a country or of a single year.

A month or a year above 1.5 °C is not enough to establish that the Paris target has been definitively exceeded. Temperatures naturally vary from year to year; the long-term climate threshold is assessed over several decades. Repeated breaches are nevertheless a signal that the planet is approaching this long-term limit.

The CAT’s optimistic scenario, at 1.9 °C in 2100, remains above 1.5 °C and close to 2 °C. The network estimates that even the full implementation of all commitments would result in a sustained overshoot of the 1.5 °C threshold. The scale and duration of this overshoot would still depend on decisions taken: cutting emissions faster remains crucial to limiting warming, even if the available figures do not promise a guaranteed return below the limit.

The key point of this update, then, is less a single figure than the distance between policies in place and announced targets. The 2.7 °C result describes the pathway associated with the former; the lower values show what increasingly complete commitments would entail. To bring these pathways closer together, announcements must be translated into effective measures.