They analysed six scenarios published between 2020 and mid-2021 by fossil fuel firms and the International Energy Agency (IEA) and calculated what the temperature outcomes for these scenarios are.
The scenarios include four from major oil firms (two from BP, one from Royal Dutch Shell, and one from Equinor), and two from the IEA.
The results show that most of the evaluated scenarios would be classified as 'Lower 2°C pathways' or those that keep peak warming below 2°C with a 66 per cent likelihood or more.
Dr Robert Brecha, co-lead author of the study from Climate Analytics, said: "Most of the scenarios we evaluated would be classified as inconsistent with the Paris Agreement as they fail to limit warming to 'well below 2°C', let alone 1.52°C, and would exceed the 1.52°C warming limit by a significant margin."
Equinor's 'Rebalance' scenario peaks at a median warming of 1.73°C above pre-industrial levels in 2060, BP's 'Rapid' at 1.73°C in 2058, Shell's 'Sky' at 1.81°C in 2069, and the IEA's sustainable development scenario (SDS) at 1.78°C in 2056. BP's Net Zero scenario results in a median peak warming of 1.65°C, too high to be consistent with the Paris Agreement criteria – every fraction of a degree matters.
Only the International Energy Agency (IEA) Net Zero 2050 scenario is aligned with the criteria for Paris Agreement consistency that the researchers applied in the study.
Bill Hare, CEO at Climate Analytics, said: "Even temporarily exceeding the 1.5°C warming would lead to catastrophic impacts and severely weaken our ability to adapt to climate change."
Last year, climate experts predicted that such a scenario could happen sooner than expected; the World Meteorological Organization (WMO) estimated a 40 per cent chance that global temperatures could temporarily exceed 1.5°C in the next five years.
Co-author Dr Robin Lamboll, from Imperial, said: "It's good that traditionally fossil-based institutions are planning for the upcoming transition to clean energy.
"However, it's important that we don't allow oil companies to mark their own work when providing suggestions for how the world can transition away from fossil fuels in a way that meets the Paris Agreement. It's also important to be aware of these biases when databases of scenarios like this are used to frame what is possible and what is 'radical' in terms of climate goals."
While the development of renewable energy sources in the analysed scenarios is similar to that in other scenarios that meet the Paris Agreement goals, they project notably high coal and gas use. Some scenarios offset the emissions from coal use with reforestation, but the analysis shows this is insufficient.
"Although protecting existing forests and afforesting more regions is good, in a world of limited land and increasingly challenging growing conditions, it is unwise to rely too heavily on forests to save us from continued use of fossil fuels," Lamboll added.
"Furthermore, coal use is particularly noxious for health reasons quite unrelated to climate change, and should not play a role in our future even if we can grow forests or deploy negative emissions technologies to counteract the carbon."
In May, a study found that even drastic cuts to carbon dioxide emissions will not be enough to prevent global warming without also cutting other climate pollutants such as methane.
