Nearly a billion people could be protected from dangerous heat if countries manage to contain global heating to 1.5C, the threshold of the Paris climate pact, notes study
Global heating due to climate change will push billions of people outside the ‘human climate niche’ in which humankind has thrived for ages, a new research has revealed.
Extreme heat will oust 600 million Indians from their climate niche, exposing them to extreme temperatures by 2030, it added.
Exposure outside this favourable niche could result in increased morbidity, mortality, adaptation and displacement; decreased cognitive performance; impaired learning; adverse pregnancy outcomes; decreased crop yield potential, as well as increased conflict, hate speech and infectious disease spread, noted the study published in the journal Nature Sustainability on May 22, 2023.
Read more: Heatwaves, droughts, extreme rain may be near permanent in 20 countries at 1.5°C warming
With rising temperatures, over two billion people worldwide could be thrown out of the range, putting them at risk of higher death rates, lower food production and economic growth by 2030. Currently, over 60 million people live outside the human climate niche. The number is expected to surge to 3.7 billion by 2090.
However, a sixth of humanity — roughly a billion — could be protected from dangerous heat if countries manage to contain global heating to 1.5C, the threshold of the Paris climate pact, the study noted.
In the study Quantifying the human cost of global warming, scientists estimated the impacts of exposure to extreme weather and temperatures on humans. Given the world is on the verge of reaching 2.7 degrees Celsius, a billion could migrate to cooler places. Considering the Mean Annual Temperature (MAT) above 20 degrees Celsius and the world population of 9.5 billion in the future, India will have more than 600 million people exposed to extreme temperatures, the document said.
India is the most vulnerable or at the ‘greatest future risk’ country. The United Nations Population Fund estimates India’s population to be over 1.4 billion, which means climate vulnerability will affect almost half the country’s residents.
Tim Lenton, professor at the University of Exeter, the United Kingdom and the first author of the study, told Down To Earth:
India’s population will certainly face serious challenges, and some will face potentially fatal heat-humidity extremes at times of the year, as we already see in parts of India. The instances and frequency of the same will increase.
Lenton said the extreme conditions could bolster adaptation measures but may also lead to widespread migration of people within India as well as out-migration elsewhere.
“People’s response will depend on their capacity to adapt, including their financial means and the government support they get (or don’t) to cope with the situation,” he said.
A lot could be done right now to reduce exposure for poorer people. For example, increased green space in cities can cool temperature extremes considerably, he said. Considering the poor infrastructure and preparedness of the government, heat extremes could worsen the situation of vulnerable populations.
Extreme heat will certainly aggravate the challenges of limited capacity and governance. If the government do not come to the people’s aid, then they will naturally fend for themselves and try to reduce their vulnerability, he said
“Grassroots political movements have a strong and proud tradition in India, and I expect to see more of those in response. There are amazing examples in human history of communities coming together in times of extreme adversity. Let&rsquo's hope we see that version of events,” he said.
On being asked whether the Indian sub continent would become unliveable or be under mass population decline due to climate change, Lenton said, “Let’s hope there would not be a major impact on population, although some increased mortality and reduced population growth may be expected.”
However, he said the major concern is that the extreme temperatures will lead to poorer quality of life, shorter life expectancy, etc, for hundreds of millions of people. “That is why it is so vital to act to reduce the level of future global warming and to have practical policies to help people (especially poorer people) to adapt.”
The study revealed that the majority of the global population lived in MAT, ranging between 13 and 25 degrees Celsius. Apart from India, Nigeria will be affected, with 300 million people moving outside the human climate niche. The other nations at risk are Indonesia, the Philippines and Pakistan.
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