Scientists constantly investigate the state of our planet and our greenhouse gas emissions and policy choices. This allows them to make projections about what our climate will look like in the future, based on different paths we might follow. Based on current policy choices, scientists have recently said that the previous ‘worst-case scenario’ (known as RCP 8.5) is now off the table. That scenario, which had foreseen a 3.5-5.5°C rise in global temperatures by 2100, is no longer considered plausible. This is a sign of progress in climate action, but not a reason to stop acting, or to doubt the science. Here are five facts to help shed some light on the latest news:
1. Climate scientists have updated their projections for the future
A key group of climate science experts has recently published an update to its scenarios for future climate change. They now focus on seven scenarios presented in an open-access peer-reviewed study (2025) which exclude both the highest and lowest emission scenarios previously envisaged. This streamlining of scenarios is both good and bad news. The discounting of the ‘worst case scenario’ is due to successful climate mitigation efforts, but the removal of the ‘best case scenario’ reflects that climate action is not going fast enough. The new scenarios presented in the study, form the basis for future climate research, including the crucial 7th Assessment Report (AR7) of the Intergovernmental Panel on Climate Change (IPCC). This is the reference for multilateral climate policy making, representing the best available science on the future of our planet.
2. The highest emission scenario (RCP8.5) is no longer considered plausible
The positive news from this update is that the new range of scenarios excludes the very high-emission scenario called RCP8.5 (also known as SSP5-8.5) from the range of plausible futures. Such a scenario had projected a staggering 3.5-5.5°C rise in global temperatures by 2100, as a result of a possible surge in fossil fuels.
The fact that scientists now deem this scenario implausible suggests that the Paris Agreement is yielding results, and that climate policies are effectively slowing the growth of global greenhouse gas emissions. To be clear, this is not a sign of mistakes in the science, but of evolution in policy choices and low-carbon technology deployments since the previous analysis.
However, it is crucial to acknowledge that even what is now the most plausible high-emissions scenario would still result in a 3.5°C increase in temperatures by the end of the century, with continued warming thereafter, not ruling out a potential rise of up to 4°C by 2100.
3. But keeping global warming well below 2°C, pursuing 1.5°C, is also getting harder
At this point in time, the most optimistic path – the new ‘best case scenario’ – would still lead to global warming of 1.7° C, temporarily exceeding the 1.5° C target in the Paris Agreement. So, there is still a need to accelerate our mitigation efforts.
This does not yet mean that we have missed the long-term Paris Agreement goal, but it is important to recognise the reality and impact of this temperature overshoot. Every fraction of a degree has increasing impacts on our health, security and prosperity. Temporarily exceeding the 1.5°C threshold will have negative effects, but we can get back on track.
The focus now should be on increasing the chances of keeping within the ‘best case scenario’. This includes limiting the duration and scale of the overshoot, to limit peak warming and get back to 1.5°C of warming as soon as possible.
4. Past results of climate modelling remain relevant, but risks tend to be revised upwards
It’s important to note that the new scenario range is a result of the actions taken worldwide to mitigate global warming. The new framework does not question past results of climate modelling. In fact, climate scientists have been accurately predicting global warming, not overestimating it. The current observed global temperatures are within the range of projections made by climate models
Nevertheless, although it remains within the range of projections, recent studies have shown that global warming has accelerated over the last decades. Looking beyond global warming and more at the risks it poses, high risks were assessed to occur at lower global warming levels in the last Assessment Report of the IPCC, compared to its previous evaluations. This reinforces the urgent need for robust climate action, encompassing both mitigation and adaptation measures, at the EU and global levels.
5. The cost of inaction is staggeringly high
The costs of climate change are already extremely high with losses in the EU amounting to EUR 40 billion in 2024, EUR 45 billion in 2023 and EUR 58 billion in 2022, as reported by the European Environment Agency.
The Commission has projected that EU GDP could be 7% lower by the end of the century under a high warming trajectory than under a 1.5°C scenario, leading to huge cumulative losses over the coming decades.
Extreme weather events such as coastal floods, wildfires, droughts and water scarcity, sea level rise and higher average temperatures are already posing a massive risk to public health and the economy. As these events are predicted to increase and become more intense, so will the associated impacts on labour productivity and health, and impacts on key infrastructure including transport and power generation.
The European Climate Risk Assessment (EUCRA) provides a comprehensive assessment of the types of risks that the EU and its Member States are exposed to in the coming decades. It provides a strong call for action to mitigate emissions and ensure that the EU improves its resilience to climate change.
Conclusion
It is encouraging that the scientific community no longer considers RCP8.5, the previous ‘worst case scenario’, among the plausible future scenarios. This reflects real progress in global climate action. But the scenarios that remain plausible are still deeply concerning. Urgent and sustained climate action is essential.
And beyond the imperative to protect life on Earth, decarbonisation delivers tangible societal benefits for Europe, such as energy independence, growth in competitive clean technology sectors, reduced damages from extreme events and fewer deaths and illnesses from air pollution.
