Projections of Warming in 2100

Future temperatures depend on two factors: future greenhouse gas emissions and the Earth’s physical response to those gases. Although significantly less warming is now expected by 2100 than was projected just a decade ago, current policies and climate pledges remain insufficient to limit warming to well below 2 °C – the central goal of the 2015 Paris Agreement.

There are two main sources of uncertainty when scientists try to estimate the levels of future warming. One is uncertainty about future greenhouse gas emissions, which directly affect warming. The other is the uncertainty in the climate sensitivity and the precise response of the climate system to higher greenhouse gas concentrations and other changes in the atmosphere. Both are shown in the graph.

The three depicted scenarios represent different emission pathways.¹ For each scenario, scientists estimate the amount of greenhouse gas emissions expected to be released in the future.

With these estimates of future emissions, scientists run a climate model to project future warming. But even with their increasing understanding of the climate system, they do not know precisely how the Earth will respond – for example, exactly how much CO₂ the oceans will absorb or how clouds will change as the planet warms. Because of these factors, warming projections are always given as a likely range. For example, in the Policies & action scenario, the projected range for 2100 is 2.1 °C to 3.3 °C. The best estimate of 2.6 °C represents the median outcome (a 50% chance of being higher or lower). The full range indicates where warming is likely to fall with a 68% level of confidence.

What are the three scenarios?

• Policies & action: This scenario is based on current actions and policies already enacted into law or under significant development. It is important to note that this is not a “worst-case” scenario; it actually assumes that current climate policies enacted into legislation (such as that in the EU) will be successfully implemented and emissions reduced. If these measures are rolled back or delayed, warming could be significantly higher than this scenario projects.

• Binding targets & pledges: This scenario assumes countries meet the formal emission reduction targets and long-term strategies they have submitted under the UN Paris Agreement. This covers both the 2030 & 2035 targets and net zero emissions pledges, including pledges for 2050 (EU, UK, Japan, South Korea, Canada, Australia, Brazil, and other countries), 2060 (China, Indonesia), and 2070 (India).

• All targets & pledges: This is the most optimistic pathway. It assumes that governments will meet every climate target, proposal, and informal announcement they have made, even those not yet formally submitted as binding international pledges. This is currently the only scenario in which warming is projected to peak before 2100 and stabilize rather than continue rising.

Footnotes

1. The graph is based on the Climate Action Tracker (CAT) Thermometer, version from November 2025, data were retrieved on 2026-02-04. Credit to: © 2025 by Climate Analytics and NewClimate Institute [https://climateactiontracker.org/global/cat-thermometer/]. ↩