Paris Agreement
The threshold values of 1.5 °C and 2 °C global warming have a special significance. In the Paris Agreement, global leaders decided that we should aim to keep global warming “well below 2 °C above pre-industrial levels” and that we should “pursue efforts to limit the increase to 1.5 °C”.
We are about to cross the 1.5 °C threshold.
Acceleration since 2011
The year 2011 marks the beginning of an acceleration of global warming, according to a recent analysis of global data over the period 1971–2025. During 1971–2010, the rate of global warming was 0.18 °C per decade. During 2011–2025, this rate doubled to 0.40 °C per decade.
This increase is partly due to the reduction of air pollution. Anthropogenic aerosols exert a substantial cooling influence on global temperatures. Since around 2010, aerosol emissions have declined markedly because of air-pollution controls and the implementation of low-sulphur shipping regulations. Also, the exceptional warmth observed during 2024 and 2025 plays an important role in the observed acceleration of global warming rate.
2028 or 2929?
The authors of this study extrapolated the rate of global warming and concluded that the 1.5 °C threshold will be crossed by 2028, nearly a decade earlier than previous estimates.
In another study, analysing observations and model projections, it was concluded that the 1.5 °C threshold will be reached in 2029. This study also provides an estimate of the year in which the 2 °C threshold will be reached: 2042. In fact, the authors concluded that current warming is already statistically indistinguishable from a 1.5 °C world.
High-latitude regions have warmed up the most, up to 3.3 °C in the Russian Arctic. Ocean-dominated regions, including parts of South America, Asia and New Zealand, have warmed up the least, approximately 1.0 °C.
2026!
The global warming threshold of 1.5 °C is already a thing of the past. The current El Niño will cause global temperatures in 2026 and 2027 to exceed the level of a 1.5 °C warmer world, Carbon Brief concluded recently.
These results agree with last year’s estimate of the famous climate researcher James Hansen and several colleagues who argued that we have already reached the +1.5 °C threshold of the Paris Climate Agreement.
Sources:
- Li et al., 2026. Nature Climate Change
- Jin et al., 2026. Climate and Atmospheric Science
- Hausfather, 3 November 2026. Carbon Brief
