Paris Agreement dials down climate risks, but danger from heat is growing

SINGAPORE – A decade since the 2015 United Nations Paris Agreement – the world’s most sweeping climate pact – was adopted by 195 parties, the danger from global warming has slightly receded.

But current emissions pledges still put the planet on course for a dangerously hot future, and a global team of scientists has mapped out just how hot that future will be in a study published on Oct 16.

Every 0.1 deg C reduction in warming can make a life-saving difference and underscores the need to double down on efforts to slash greenhouse gas emissions and ramp up adaptation measures to searing heat.

The world now experiences, on average, an additional 11 hot days a year since the Paris Agreement was adopted, as growing fossil fuel emissions trap more heat in the atmosphere.

And there will be an additional 57 such days a year by 2100, based on national emissions reduction pledges submitted under the Paris Agreement, said scientists from Climate Central, a US-based group of scientists and communicators, and World Weather Attribution (WWA), an international scientific collaboration.

That does not sound like good news.

But the scientists point out that before the pact was adopted in December 2015, the world was on track for 4 deg C of warming above pre-industrial levels by the end of this century.

And that would mean the world would experience an average of 114 more hot days a year by 2100, the researchers said in the study released less than a month before the COP30 UN climate talks in Brazil.

“Hot days” in this context are days with temperatures warmer than 90 per cent of temperatures observed at a location over the 1991-2020 period. These are days with temperatures that people would consider hot based on their local experience.

The Paris Agreement has helped dial back climate risks in several key ways. It enshrined the goal of reaching net-zero emissions by mid-century and, every five years, nations have to submit updated and more ambitious climate plans to the UN. This ratcheting mechanism is meant to drive deeper emissions reductions.

Collectively, those national plans have become stronger, but much deeper and faster emissions cuts are still needed, the UN says.

“The Paris Agreement is a powerful, legally binding framework that can help us avoid the most severe impacts of climate change,” Dr Friederike Otto, professor of climate science at the Centre for Environmental Policy at Imperial College London, said in a statement.

“Political leaders need to take the reason for the Paris Agreement much more seriously. Every fraction of a degree of warming – whether it is 1.4, 1.5 or 1.7 deg C – will mean the difference between safety and suffering for millions of people,” she added.

Heat is the deadliest type of weather, causing an estimated half a million deaths each year, and the threat is often underestimated because the impacts are less visible, experts say.

The world is on track to warm 2.6 deg C this century if the current Paris pledges are fully implemented, according to

a 2024 UN analysis

.

That is still far above the Paris guard rail of keeping warming below 2 deg C, with the aim of limiting warming to 1.5 deg C.

The world has already warmed about 1.4 deg C – an increase of about 0.4 deg C in the past decade.

And that is the key problem – climate change is outpacing global action, and adaptation.

Over the past decade, countless heat records have been shattered globally, with 2023 and 2024 being the hottest years. And, increasingly, ocean temperature records are being broken, too.

In Asia, Indonesia and Malaysia had the highest increase in annual average hot days, the scientists found.

In the decade before the Paris pact (2005 to 2014), Indonesia and Malaysia had 45 and 36 hot days a year, respectively. In the decade after (2015 to 2024), this rose to 63 and 53, respectively.

But at 2.6 deg C of warming, the number of hot days is set to jump to 134 for Indonesia and 125 for Malaysia. At 4 deg C, it is set to soar to 248 for Indonesia and 243 for Malaysia.

Dr Kristina Dahl, vice-president for science at Climate Central, said in the same statement: “The Paris Agreement is helping many regions of the world avoid some of the worst possible outcomes of climate change.

“But make no mistake – we are still heading for a dangerously hot future. The impacts of recent heatwaves show that many countries are not well prepared to deal with 1.3 deg C of warming, let alone the 2.6 deg C of warming projected if – and it’s a big if – countries meet their current emissions reduction pledges.”

The scientists also looked at the role climate change has played in six major heatwave events globally, including the deadly South Asia heatwave from March to May in 2022, and estimated the likely severity as global temperatures increase.

Scientists from WWA analysed weather data and climate models using peer-reviewed methods to compare how heatwaves have changed between climates with human-caused warming and the cooler pre-industrial climate with no human influence.

Dozens, and likely many more than that, died in the weeks-long 2022 heatwave in India and Pakistan that also withered wheat crops and triggered flooding from melting glaciers.

WWA analysis shows that the abnormally high pre-monsoon temperatures in 2022 were about 30 times more likely and 2.1 deg C higher than they would have been without human influence.

Without emissions reductions – meaning, a 4 deg C pathway – the temperatures of 2022 would be expected every two years and would be about 14 times more likely and 3.3 deg C higher than today.

Heatwaves in southern Europe have proved to be especially deadly. Europe is warming at about twice the global average rate, making it the fastest-warming continent. An estimated 16,600 people died across European cities during the summer of 2025.

A week-long severe heatwave like the one in 2023 is now 70 per cent more likely and involving temperatures higher by 0.6 deg C than a decade ago.

If current emissions targets are met, similar heatwaves could be characterised by temperatures 3 deg C higher in a world 2.6 deg C warmer; in a climate 4 deg C warmer, temperatures during heatwaves would be 6 deg C higher than today, the researchers said.

As the heat threat grows, nations need to put in place better adaptations for heat, and craft national heat plans, the scientists said.

In March, the Singapore Government unveiled a raft of measures to

help reduce the risks from rising heat,

including a network of public cooling spaces, suspending certain outdoor activities during peak heat, and having schools possibly shift to home-based learning if the need arises.

The plan also sets out a national approach on how various sectors should respond during a heatwave.

Dr Joyce Kimutai, a researcher at the Centre for Environmental Policy at Imperial College London, said: “Cutting emissions alone won’t be enough. We also need to triple our adaptation efforts to protect lives.”