New findings has predicted that 2.7°C of warming will disproportionately harm African countries.

The findings, which was published May 22, 2022 in the Nature Sustainability journal, is entitled: “Quantifying the Human Cost of Global Warming".

The figure would be much smaller at 1.5°C, at 90 million. At 2.7°C global warming, Nigeria would have the second-largest heat-exposed population, with almost 300 million people.

This would be less than 40 million with 1.5°C warming. Already, India and Nigeria have "hotspots" with deadly temperatures.

Nearly 100% of some countries, including Burkina Faso and Mali, will be extremely hot for humans at 2.7°C.

The study also discovered that exposure to harmful heat begins to rise rapidly around 1.2°C (just above current global warming) and rises by approximately 140 million for every 0.1°C of additional warming.

With a potential population of 9.5 billion people, India would have the most people exposed to 2.7°C global warming - more than 600 million.

Despite nearly little territory being exposed at 1.5 °C, Brazil would have the most land area exposed to harmful heat. Australia and India would also see large increases in exposed area.

It said that limiting warming to 1.5°C would rescue a sixth of humankind from deadly heat, compared to 2.7°C, highlighting the critical need for swift action to decrease carbon emissions.

The study – led by researchers at the Global Systems Institute, University of Exeter, and Nanjing University – starkly demonstrates how the narrow subset of Earth’s inhabitable climate (the “climate niche”) is rapidly shrinking, putting millions in the future at risk – especially those living in the lowest emitting areas today.

The new study looked at what this might entail for the number of people who live outside of the "climate niche" where species thrive.

According to recent research, current climate policies will expose more than a fifth of humanity to dangerously high temperatures by 2100.

Despite the Paris Agreement's goal to limit global warming to less than 2°C (relative to pre-industrial levels), present policies are expected to result in 2.7°C warming by the end of the century.

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 of these impacts can be avoided by rapid action to cut greenhouse gas emissions.

Wageningen University Professor Marten Scheffer said, the desire was sparked by the reality that the economic consequences of carbon emissions do not adequately represent the impact on human wellbeing.

“Our calculations now help bridge this gap and should stimulate asking new, unorthodox questions about justice,” Prof. Scheffer said.

Ashish Ghadiali, of Exeter’s Global Systems Institute, said: “These new findings from the leading edge of earth systems science underline the profoundly racialised nature of projected climate impacts and should inspire a policy sea-change in thinking around the urgency of decarbonisation efforts as well as in the value of massively up-shifting global investment into the frontlines of climate vulnerability.”

The Open Society Foundations supported the research, and the document is also an output of the Earth Commission, which was convened by Future Earth and is the scientific foundation of the Global Commons Alliance.

Wendy Broadgate, Executive Director of the Earth Commission at Future Earth, also stated that the world is already experiencing the effects of dangerous heat levels on people in various parts of the world today, and that this will only worsen unless immediate and decisive action to reduce greenhouse gas emissions is taken.

The Global Systems Institute at the University of Exeter has found "positive tipping points" to expedite action, including a recent paper that identified three "super-leverage points" that might unleash a decarbonisation cascade.