Climate Analytics warns that exceeding 1.5°C is now unavoidable, but halving global emissions by 2035, phasing out fossil fuels and cutting methane could limit peak warming to 1.7°C and bring temperatures back down by 2100.
Global warming overshoot: why returning below 1.5°C is still possible
Halving global emissions by 2035, accelerating the phase-out of fossil fuels and reducing methane emissions are essential steps to limit global warming overshoot. According to Climate Analytics, it is still possible to keep peak warming at around 1.7°C by 2040 and bring global temperatures back down to 1.2°C–1.3°C by the end of the century.
Exceeding the 1.5°C global warming threshold above pre-industrial levels is now inevitable, but there is still time to limit how far temperatures rise and how long they remain above that threshold.
This is the main finding of the new report, Climate overshoot: The way back below 1.5°C, published by the research institute Climate Analytics during COP31.
“The overshoot we are facing is now inevitable. It is not a question of physics, but of political choice,” warns Bill Hare, CEO of Climate Analytics.
“How long we remain above 1.5°C, how quickly temperatures subsequently decline and how far they fall will depend on the measures governments take now and in the coming years,” he adds.
The impacts of exceeding 1.5°C
Every additional tenth of a degree increases climate risks, from greater exposure to extreme heat and rising sea levels to the possibility of triggering irreversible changes in ecosystems.
According to the report, if global warming reaches 1.7°C instead of 1.5°C by 2050, the number of people exposed to heatwaves could increase by around one-third worldwide.
If temperatures rise to 1.8°C by 2050, exposure could increase by a further 10%.
Among the most significant risks are the loss of coral reefs, the melting of the Greenland and West Antarctic ice sheets, and the deterioration of the Amazon rainforest.
Limiting both the peak and duration of the overshoot would therefore help reduce these impacts.
Halving emissions by 2035 and phasing out fossil fuels
The most important step is moving away from fossil fuels, which account for more than 70% of global greenhouse gas emissions.
According to the analysis, coal consumption must fall by around 70% by 2035, gas consumption by 50% and oil consumption by more than a quarter.
Renewable energy sources should progressively replace fossil fuels in electricity generation, while clean electricity should be used to decarbonise transport, buildings and industry.
These measures must be accompanied by improvements in energy efficiency, reductions in methane emissions and the restoration of natural ecosystems.
Methane is one of the most urgent areas for action. Responsible for around one-third of the warming recorded so far, methane emissions should fall by up to one-third by 2030.
“Because methane remains in the atmosphere for a relatively short time, cutting methane emissions is the fastest way to slow warming immediately,” explains Zarrar Khan, Senior Expert in Integrated Assessment Models at Climate Analytics.
Electrification and renewable energy must advance together
Accelerating electrification is another key measure identified in the report.
It is also a central issue on the COP31 agenda, particularly through the 35-by-35 initiative, which aims to increase the global electrification rate by 35% by 2035.
For Climate Analytics, however, this target should be considered a starting point.
Under the institute’s most ambitious scenario, the electrification rate would need to reach approximately 39%.
The growing share of electricity in final energy consumption must also be matched by the decarbonisation of electricity generation.
“You can have strong electrification, but you have to ask whether it is meeting new demand or replacing fossil fuels,” Khan points out.
If electricity continues to be generated from fossil fuels, electrification may fail to deliver meaningful emissions reductions.
There must be “electrification on the one hand, but also decarbonisation of the energy sector on the other. […] Electricity must therefore come from clean sources.”
The pathway also requires an increase in the removal of CO₂ from the atmosphere.
Under the most ambitious scenario, which would bring temperatures back down to 1.2°C–1.3°C by 2100, carbon removal would need to reach approximately 500 billion tonnes over the course of the century.
The report stresses that carbon removal must complement, rather than replace, emissions reductions and the phase-out of fossil fuels.
Hare’s appeal at COP31 is to “act to keep the overshoot as low as possible, make it last for as short a time as possible, and return below 1.5°C as quickly as possible.”
