World can still return below 1.5°C by 2100 with urgent action: Study

The world can still bring long-term average global temperature rise back to well below 1.5 degrees Celsius this century but only if countries immediately pursue the "highest possible ambition" in climate action, according to a new analysis published on Thursday.

The study, titled "Rescuing 1.5 degree C: New Evidence on Highest Possible Ambition to Deliver the Paris Agreement", by Berlin-headquartered climate science and policy institute Climate Analytics updates earlier UN climate models to reflect today's higher emissions and finds that transformative action led by rapid electrification, renewable expansion and a fossil fuel phaseout could halt global warming before mid-century.

The report's "Highest Possible Ambition" (HPA) scenario shows global warming peaking around 1.7 degrees Celsius around 2040 before falling to about 1.2 degrees Celsius by 2100.

It projects global carbon dioxide emissions reaching net zero by 2045 and all greenhouse gases by the 2060s -- roughly a decade earlier than in the latest IPCC pathways.

Under the HPA scenario, renewable electricity would supply nearly two-thirds of all energy demand by 2050, with wind and solar meeting over 90 per cent of electricity needs.

Fossil fuel use peaks immediately and declines sharply; coal is effectively phased out by the 2040s, gas in the 2050s and oil in the 2060s. Advanced economies would reach a fossil-free energy system by 2050, with the rest of the world following by 2070.

Methane emissions would fall 20 per cent by 2030 and 30 per cent by 2035 compared to 2020 levels, driven mainly by cuts in the energy sector. Carbon dioxide removal technologies, including direct air capture and engineered removals, would need to scale up rapidly, capturing over 5 billion tonnes of CO2 annually by 2050.

The Paris Agreement, adopted by nearly 200 countries in 2015, aims to keep global temperature rise well below 2 degrees Celsius and pursue efforts to limit it to 1.5 degrees Celsius. Warming has already crossed 1.3 degrees Celsius and global emissions continue to rise.

According to the World Meteorological Department, 2024 was the hottest year on record and the first with a global average temperature 1.5 degrees Celsius above pre-industrial levels.

However, a permanent breach of the 1.5-degree Celsius limit specified in the Paris Agreement refers to long-term warming over a 20- or 30-year period.

The Climate Analytics report said the world will very likely reach 1.5 degrees Celsius of warming by the early 2030s.

The global average concentration of carbon dioxide surged by 3.5 parts per million from 2023 to 2024, the largest increase since modern measurements started in 1957.

"Overshoot of 1.5 degrees Celsius is a woeful political failure and will bring increased damages and risk of tipping points that otherwise could have been avoided. But this roadmap shows it is still within our power to bring warming back well below 1.5 degrees Celsius by 2100," said Bill Hare, CEO of Climate Analytics.

"We must do all we can to limit any time we spend above this safety threshold to minimise the risk of irreversible climate damages and the devastation that could be caused by crossing tipping points."

The analysis warned that a temporary overshoot of 1.5 degrees Celsius, expected to last about four decades, will have significant consequences for vulnerable countries, ecosystems and global inequality.

But it also finds that swift emissions cuts, combined with a revolution in renewables and batteries, could help reverse that trend before the end of the century.

Neil Grant, Senior Expert at Climate Analytics and lead author, said, "The last five years have cost us precious time in the critical decade of climate action.

"However, they have also seen a revolution in renewables and batteries, which have shattered records across the globe. Riding these tailwinds can help turbocharge our clean energy future and catch up on lost time. The window to minimise overshoot is still open, but narrowing fast."