Two billion people face exposure to ‘dangerous heat’ by 2100, study finds

23rd May 2023


Shutterstock 2180966313

Related Topics

Author

Chris Seekings

The number of people exposed to dangerously hot temperatures will increase from around 60 million today to two billion by 2100 under current climate policies, a new study has found.

This would represent 22% of the projected end-of-century population living with "dangerous" average temperatures of 29°C or higher.

However, limiting global warming to 1.5°C above pre-industrial levels, rather than a projected 2.7°C, would leave just 5% of the population exposed – saving a sixth of humanity from the extreme temperatures.

The study, led by researchers at the University of Exeter’s Global Systems Institute, highlights the “huge potential” for decisive climate policy to limit the human costs and inequities of climate change.

In “worst-case scenarios” of 3.6°C or even 4.4°C of global warming, it suggests that half of the world’s population could be exposed to dangerous heat.

“The costs of global warming are often expressed in financial terms, but our study highlights the phenomenal human cost of failing to tackle the climate emergency,” said professor Tim Lenton, director of the Global Systems Institute.

“For every 0.1°C of warming above present levels, about 140 million more people will be exposed to dangerous heat. This reveals both the scale of the problem and the importance of decisive action to reduce carbon emissions.

“Limiting global warming to 1.5°C rather than 2.7°C would mean five times fewer people in 2100 being exposed to dangerous heat.”

Human population density has historically peaked in places with an average temperature of about 13°C, with mortality increasing below and above this threshold, according to the study.

Assuming a future population of 9.5 billion people, it suggests that India would have the greatest number of people exposed to dangerous temperatures under 2.7°C of global warming – with more than 600 million.

However, under 1.5°C of global warming, this figure would be about 90 million.

Nigeria would have the second-largest heat-exposed population under 2.7°C of global warming, on more than 300 million, but less than 40 million under 1.5°C of warming.

The research team – which included the Potsdam Institute for Climate Impact Research, the International Institute for Applied Systems Analysis, and the Universities of Washington, North Carolina State, Aarhus and Wageningen – stress that the worst impacts can be avoided by rapid action to cut greenhouse gas emissions.

Speaking about the conception of the study, professor Marten Scheffer, of Wageningen University, said: “We were triggered by the fact that the economic costs of carbon emissions hardly reflect the impact on human wellbeing.

“Our calculations now help bridging this gap, and should stimulate asking new, unorthodox questions about justice.”

Image credit: Shutterstock


Transform articles

‘Eco-anxiety’ under the spotlight at IEMA Connect 2023

Turning ‘eco-anxiety into eco-action’ was discussed at IEMA Connect 2023 this morning, providing key research and tips to help sustainability professionals deal with feelings of environmental despair.

21st September 2023

Read more

The UN has published its first official ‘global stocktake’ of progress tackling climate change since the Paris Agreement, which shows that ambition and implementation “must be accelerated rapidly”.

14th September 2023

Read more

The UN Environment Programme (UNEP) has this week published a plan to decarbonise the world's buildings and construction sector using an “avoid-shift-improve” solution.

14th September 2023

Read more

Almost half of UK adults feel worse about the climate crisis due to government policy, with one in six suffering with ‘eco-anxiety’, new research suggests.

12th September 2023

Read more

The UK needs a new public investment fund that provides green companies with finance in exchange for part ownership and a share of future profits, a think tank has suggested.

25th August 2023

Read more

Countries in the Global South are trapped in relying on fossil fuel production to repay debts, a new report from the charity Debt Justice claims.

22nd August 2023

Read more

A total of 25 countries – home to a quarter of the global population – face extremely high water stress each year, regularly using up almost their entire available renewable supply.

17th August 2023

Read more

A lack of expert staff at environmental organisations is undermining the UK’s government’s net zero and nature commitments, new research by the trade union Prospect has uncovered.

16th August 2023

Read more

Media enquires

Looking for an expert to speak at an event or comment on an item in the news?

Find an expert