Representative image. (Sanjay Hadkar/TOI/BCCL)
Representative image. (Sanjay Hadkar/TOI/BCCL)

While world leaders continue to offer paltry consolations in the name of climate action, a recent study has shown that the policies currently being implemented to limit global warming are not enough. We’ve known this, of course, but what we didn’t know was that this could endanger over a fifth of humanity by 2100.

As per new research, Earth’s surface temperature is projected to increase by 2.7°C (4.8°C) by the end of the century, well outside the climate comfort zone that has supported the survival of our species for millennia. And estimates suggest that it would push more than two billion people — or 22% of the projected global population — to extreme and potentially life-threatening heat.

What’s even more alarming is that India will be the worst hit, with the unprecedented heat likely to impact 600 million people. India will be followed by Nigeria (300 million), Indonesia (100 million), as well as the Philippines and Pakistan (80 million each).

Lead author Tim Lenton, director of the Global Systems Institute at the University of Exeter, thinks that this could significantly reshape the habitability of the surface of the planet and could potentially lead to the large-scale reorganization of where people live.

The study also showed that lifetime emissions of 3.5 average global citizens today – or just 1.2 US citizens – expose one future person to dangerous heat. Given that these people would live in areas where current emissions are only about half as high as the global average, this illustrates the injustice of the climate catastrophe.

Furthermore, in “worst-case scenarios” of 3.6°C or even 4.4°C global warming, 50% of the world’s population could be left outside the climate niche, resulting in what the researchers call “existential risk”.

However, there is hope yet. As per the study’s authors, limiting global warming to the 2015 Paris climate treaty objective of 1.5°C would drastically reduce the number of persons at risk to fewer than half a billion. This would be about 5% of the 9.5 billion people who are expected to inhabit the world in the next six to seven decades.

The new study illustrates the human cost of failing to tackle the climate emergency as opposed to financial costs.

“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,” said Professor Tim Lenton, director of the Global Systems Institute at the University of Exeter.

The study’s findings have been detailed in Nature Sustainability and can be accessed here.