This is the Englisch translation and update of a study published by the authorsMay 15, 2025. Based on two statistical methods for estimating future global warming from the actual data of the last 20 years and the IPCC approach for ascertaining sustained global warming reached by a given year, this study comes to the conclusion that with 95% probability the 1.5 °C threshold of the Paris Agreement was exceeded by 2024. the 2.0 °C threshold will be exceeded by 2032 if GHG emissions continue as they have. GHG emissions need to be reduced by 8% per year and reach net zero by 2038 if global warming is to be limited to 2.0 °C. Even then, lagging effects may well global warming to 2.5 °C in the years after 2038. These results show a need for decisive action by UN, EU, IPCC and national governments: Clearly acknowledge that the 1.5 °C Paris Agreement threshold has been exceeded and that now the pressing challenge is not to exceed 2.0 °C, with every 0.1 °C counting. Stop global fossil fuel investment now and set 2038 as the global net zero target date That will be very challenging in the current political environment. But stating the facts andnecessary actions and taking any step in that direction are well worth the effort, since the human, environmen tal and eco nomic costs of inaction are extremely high. This study is no substitute for sophisticated climate models. But if climate models account for the acceleration of global warming in the last 20 years, it is hard to see how they could show substantially different results. Accordingly, since publication of the German version of this study, scientists using established climate models have published similar estimates, based on up to date climate data: May 28, 2025, the World Meteorological Organization published an estimate, that the20-year average glo bal warming centered around 2024 reached 1.44 °C in 2024, i.e. that 2024 was a mere 0.06 °C away from 1.5 °C. June 19, 2025, Piers M. Forster (a leading author for the IPPC) et al published an estimate that the remaining carbon budget for staying under 1.5°C global warming was or will be exhausted in the course of 2025 oder 2026.
Fischer et al. (Sun,) studied this question.