India is among the countries where weather conditions may become near unliveable in the next 50 years if greenhouse gas emissions are not reduced, according to a study published in the Proceedings of the National Academy of Sciences journal on Tuesday. Some places in India are at the risk of becoming as hot as the Sahara desert.

Apart from India, places in Pakistan, Nigeria, Indonesia and Sudan face similar risks. It would mean that 3.5 billion people would live outside the climate “niche” in which humans have thrived for 6,000 years, said the study conducted by scientists from China, the United States and Europe.

“Human populations are largely concentrated in narrow climate bands, with most people living in places where the average annual temperature is about 11-15°C (52-59°F) and a smaller number of people living where the average temperature is about 20-25°C (68-77°F),” finds the study.

If greenhouse gas emissions continue to increase unabated, temperature will rise 7.5°C by 2070. “This rapid temperature rise, combined with projected global population changes, mean about 30% of the world’s projected population – will live in places with an average temperature above 29°C within 50 years, if greenhouse gas emissions continue to increase,” said Jens-Christian Svenning from Aarhus University, a co-author of the study. “These climate conditions are currently experienced by just 0.8% of the global land surface, mostly in the hottest parts of the Sahara desert, but by 2070 the conditions could spread to 19% of the planet’s land area. This would bring 3.5 billion people into near-unliveable conditions.”

The study also pointed out that this change in the climate would pose a major threat to food production. It added that areas that are known for crop production are likely to face extreme heat.

A co-author also drew a parallel between the findings and the current coronavirus crisis. “The coronavirus has changed the world in ways that were hard to imagine a few months ago and our results show how climate change could do something similar,” the author adds. “Large areas of the planet would heat to barely survivable levels and they wouldn’t cool down again. Not only would this have devastating direct effects, it leaves societies less able to cope with future crises like new pandemics. The only thing that can stop this happening is a rapid cut in carbon emissions.” The author adds that the change would unfold less rapidly but warns that there would be no relief to look forward to.

In January, the United Nations said the past decade was the hottest on record and warned that extreme weather events were likely to prevail throughout 2020 and the coming decades. The World Meteorological Organization based its findings on an analysis of leading international datasets. The research showed that the average global temperature in 2019 was 1.1 degrees Celsius above pre-industrial levels, and was creeping towards a globally agreed limit after which major changes to life on Earth are expected.

The meteorological organisation said its research also confirmed that 2019 was the second-hottest year since records started to be kept. The previous hottest year on record was 2016, when the El Nino weather pattern pushed the average surface temperature to 1.2 degrees Celsius above pre-industrial levels, the UN body added.