Paris agreement could prevent 57 hot days annually, study finds

Scientists say a landmark agreement can help secure a safer climate but warn that a faster shift away from fossil fuels is needed. A new study has found that the 2015 Paris Agreement could help the world avoid 57 hot days annually if countries follow through on their emission-cutting plans and limit warming this century to 2.6°C.

The report by climate change watchdogs Climate Central and World Weather Attribution shows that the historic accord can help the world move toward a safer climate. However, researchers warn that 2.6°C of warming would still subject future generations to dangerous heat, cause severe health impacts, and exacerbate inequality. They call for stronger commitments and policies to accelerate the transition away from fossil fuels and keep warming well below 2°C.

KEY FINDINGS

• The report suggests that at 4°C of warming, the baseline level used in 2015 before the Paris Agreement was signed, the world would have experienced an average of 114 hot days per year.
• If countries successfully deliver on their current emission plans and limit warming to 2.6°C, the world could experience 57 fewer hot days annually.
• Six recent heat events that scorched countries around the world would be about 5 to 75 times more likely at 4°C, but only 3 to 35 times more likely at 2.6°C.
• Keeping warming well below 2°C is vital, as heat becomes more dangerous with every fraction of a degree. Since 2015, a 0.3°C increase has resulted in 11 more hot days globally and made heatwaves much more likely, including ten times more likely in the Amazon, nine times in Mali and Burkina Faso, and twice in India and Pakistan.
• Adaptation finance remains limited, and investments in early warning systems and action plans are still insufficient in many cities and countries.

EXPERT VIEWS

Prof Friederike Otto, Professor of Climate Science at the Centre for Environmental Policy, Imperial College London, said,
"The Paris Agreement is a powerful, legally binding framework that can help us avoid the most severe impacts of climate change. However, countries need to do more to shift away from oil, gas, and coal. We have all the knowledge and technology needed to transition away from fossil fuels, but stronger, fairer policies are needed to move faster."

She also added, "Political leaders need to take the Paris Agreement seriously. It is about protecting our human rights. Every fraction of a degree of warming, whether 1.4, 1.5, or 1.7°C, will mean the difference between safety and suffering for millions of people."

The 2015 Paris Agreement set the goal of keeping global temperatures well below 2°C and pursuing efforts to limit the temperature increase to 1.5°C. Today, warming has reached more than 1.3°C, and with emissions continuing to rise, some political leaders, including former US President Donald Trump, have questioned the agreement’s effectiveness.

The study shows it is helping move the world toward a safer climate. It focused on hot days, the top 10% warmest temperatures globally. At 4°C of warming, the world would have experienced an average of 114 hot days. Today, if countries deliver on their emission plans and limit warming to 2.6°C, the world could see 57 fewer hot days compared to 4°C. Specific examples include Kenya (82 fewer days), Mexico (77), Brazil (69), Egypt (36), Australia (34), India (30), the US (30), the UK (29), China (29), and Spain (27).

The study emphasises the importance of avoiding every tenth of a degree of warming. Since 2015, an additional 0.3°C of warming has added 11 more hot days per year and made heat events about 1.5 to 10 times more likely globally. Adaptation is a core part of the Paris Agreement, and measures to boost heat resilience have improved since 2015. Heat is the deadliest type of weather, causing an estimated half a million deaths annually. Historically, its danger has been underappreciated because the impacts are less visible than those of other extreme weather events.

Researchers note that campaigns and initiatives have increased global awareness about extreme heat. More countries have developed early warning systems and heat action plans, which are highly effective at reducing heat-related deaths. Today, about half of all countries have warning systems, and at least 47 have action plans in place.

Ultimately, the most effective way to protect people and minimise heat-related deaths is a rapid shift away from oil, gas, and coal.

Dr Kristina Dahl, Vice President for Science at Climate Central, said, "The Paris Agreement is helping many regions of the world avoid some of the worst possible outcomes of climate change. But we are still heading for a dangerously hot future. Recent heatwaves show that many countries are unprepared for 1.3°C of warming, let alone the 2.6°C projected if countries meet their current emission pledges. Faster, deeper, and more ambitious emission cuts are crucial to ensure future generations live in a safe climate."

Roop Singh, Head of Urban and Attribution at the Red Cross Red Crescent Climate Centre, added, "The Paris Agreement is best known for its warming targets, but we’ve also made important progress on adaptation since its signing. Heat action plans and early warning systems have steadily increased over the last decade. The danger of heat will only rise this century, so it is crucial that every country implements measures to keep people safe."

Dr Joyce Kimutai, Researcher at the Centre for Environmental Policy, Imperial College London, said, "We are on track to exceed the 1.5°C target of the Paris Agreement this century, but this does not mean we need a new goal. Warming must be kept as far below 2°C as possible. The costs of inaction are accelerating faster than progress on adaptation. Developing countries, which are least responsible for emissions, are suffering the worst impacts. We urgently need a rapid and sustained transition away from oil, gas, and coal. Developed countries, which caused most of the warming, need to lead. But cutting emissions alone won't be enough, we also need to triple our adaptation efforts to protect lives and livelihoods."

Every fraction of a degree matters. From 2015 to 2023, a 0.3°C increase in warming has added 11 more hot days per year. Delaying the shift away from fossil fuels exposes millions more people to life-threatening conditions. Countries must act ambitiously to bring warming as far below 2°C as possible.

Emmanuel Raju, Director of the Copenhagen Centre for Disaster Research at the University of Copenhagen, said, "The majority of the world, primarily in low-resource settings, is barely coping with extreme heat. This is an issue of injustice, as people are pushed beyond their limits to adapt. We know the full picture of visible and invisible impacts and the loss and damage caused by extreme heat. We need to move from survival to transformative adaptation."

The only way forward is to cut emissions and make stronger commitments. More financing for adaptation, loss, and damage is essential to safeguard lives, livelihoods, and society.

To understand how climate change influenced high temperatures, scientists from Climate Central identified local hot days by calculating the threshold temperature for the warmest 10% of temperatures from 1991-2020. Days exceeding this threshold are associated with increased health risks. They then compared the number of days exceeding this threshold to a scenario without climate change.

To quantify the effect of human-caused warming on heatwaves, scientists from World Weather Attribution analysed weather data and climate models using peer-reviewed methods to compare events in today’s climate versus a cooler pre-industrial climate. This analysis revisited six heatwaves previously studied in southern Europe, West Africa, the Amazon, Asia, Australia, and North and Central America.

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