A new Climate Analytics report warns that exceeding 1.5°C of global warming is now unavoidable, but decisive action on fossil fuels, methane emissions and clean energy could limit peak warming to 1.7°C and bring temperatures back below the threshold by 2100.
Climate overshoot: How the world could return below 1.5°C by 2100
Halving global greenhouse gas emissions by 2035, accelerating the phaseout of fossil fuels and sharply reducing methane emissions could still change the trajectory of global warming. According to Climate Analytics, it remains possible to limit peak warming to 1.7°C around 2040 and bring global temperatures down to 1.2°C–1.3°C above preindustrial levels by the end of the century.
Exceeding the 1.5°C global warming threshold is now unavoidable, but there is still time to limit how far temperatures rise above that level and how long they remain there. That is the central 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 ahead of us is now unavoidable. 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, and how quickly and how far temperatures subsequently decline, will depend on the actions governments take now and in the coming years,” he adds.
The consequences 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 critical ecosystems.
According to the report, warming of 1.7°C rather than 1.5°C by 2050 could increase the number of people exposed to heat waves worldwide by roughly one-third. If temperatures reach 1.8°C by 2050, that figure could rise by another 10%.
Among the most significant risks are the loss of coral reefs, the melting of the Greenland and West Antarctic ice sheets, and the degradation of the Amazon rainforest.
Limiting both the magnitude and duration of climate overshoot would therefore help reduce the scale of these impacts.
Halving emissions by 2035 and phasing out fossil fuels
At the heart of the proposed strategy is a transition away from fossil fuels, which account for more than 70% of global greenhouse gas emissions.
According to the analysis, coal consumption must fall by approximately 70% by 2035, natural gas consumption by 50%, and oil consumption by more than 25%.
Renewable energy would progressively replace fossil fuels in electricity generation, while clean electricity would help decarbonize transportation, buildings and industry.
These measures would need to be accompanied by improvements in energy efficiency, reductions in methane emissions and the restoration of natural ecosystems.
Methane is among the most urgent priorities. Responsible for roughly one-third of the warming recorded to date, methane emissions would need to decline by as much as 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 in the near term,” explains Zarrar Khan, senior expert in integrated assessment models at Climate Analytics.
Electrification and renewable energy must advance together
The report also calls for faster electrification, a central issue on the COP31 agenda through the 35-by-35 initiative, which aims to increase the global electrification rate to 35% by 2035.
For Climate Analytics, however, that target should be a starting point rather than the ultimate goal.
Under the institute’s most ambitious scenario, the electrification rate would need to reach approximately 39%.
Increasing electricity’s share of final energy consumption must also go hand in hand with decarbonizing power generation.
“You can have substantial electrification, but the question is whether it is meeting new demand or replacing fossil fuels,” Khan points out.
If electricity continues to be generated from fossil fuels, greater electrification may not deliver meaningful emissions reductions.
The transition therefore requires two parallel efforts: expanding electrification across the economy and decarbonizing the power sector. The additional electricity must come from clean energy sources.
The pathway also calls for a substantial increase in carbon dioxide removal from the atmosphere.
Under the most ambitious scenario, which would bring global warming back down to 1.2°C–1.3°C by 2100, cumulative carbon dioxide removal would need to reach approximately 500 billion metric tons over the course of the century.
The report emphasizes that carbon removal must complement, rather than replace, deep emissions reductions and the phaseout of fossil fuels.
Hare’s message to COP31 is clear: Keep the overshoot as low as possible, make it as brief as possible, and return below 1.5°C as quickly as possible.
