Over 9 billion across the world likely to be exposed to annual average temperatures experienced only in the hottest deserts
For over 6,000 years, humans restricted their settlements to a climate niche or set of temperatures between 11 degrees Celsius and 15 degrees Celsius mean annual temperature. But global warming could trigger the next wave of migration — and at least 3 billion people would be affected by it by 2070. India would be among the worst-hit in Asia.
A study by a group of researchers — called Future of the Human Climate Niche — projected that over 3 billion people, currently living in 0.8 per cent of the Earth’s surface that experiences average annual temperature of more than 29°C, would have to move to migrate to more places with suitable conditions.
It added that another 9 billion people would be exposed to such annual average temperatures experienced only in the hottest deserts such as the Sahara.
The study was published in Proceedings of the National Academy of Sciences of the United States of America in 2020.
The projections were analysed and visualised by Down To Earth under the worst climatic scenario, the representative concentration pathway or RCP8.5, where emissions continue to rise with no policy intervention as well as shared economic pathway (SSP5) where fossil fuels play a big role for economic growth and coupled with energy-intensive lifestyle.
The Earth is currently warming at the rate of 1.1°C. Even in the best-case scenario with emission cuts, the Earth will warm at 1.5°C in the next 20 years. This warming scenario, according to the researchers of the study, will lead to people experiencing an average annual temperature of at least 29°C across 19 per cent of the Earth’s surface by 2070.
The largest continent is going to see a massive population boom. India would be the most affected, with over half of the 1.6 billion people (projected population by 2070) exposed to extreme heat.
Other countries like the United Arab Emirates, Cambodia, and parts of south Vietnam and eastern Pakistan will become unlivable, according to the projections.
The most vulnerable of all the continents in terms of low human development, Africa is going to witness a population of 1.2 billion people and Lagos, the capital of Nigeria, is on course to become the most populous city by 2075. The study states that 81 per cent of the projected 477 million people in Nigeria would be exposed to extreme temperatures.
Europe would be the only continent that would not witness annual mean temperatures of more than 29°C but parts of Scandinavia, eastern Russia and countries along the Mediterranean will experience a rise in temperatures.
Already under scrutiny because of refugees flocking from war-torn countries, it remains to be seen how global warming would affect Europe in terms of migration.
North and South America
Large parts of Brazil, currently inhabited by the indigenous tribes of the Amazon, could become inhospitable under the worst climatic scenario. Southern states in the United States will experience a rise in temperatures.
Up to 20 million people would live in regions with an annual average temperature of at least 29°C.
Extreme temperatures will be restricted to sparsely-populated regions of Papua New Guinea and northern Australia in Oceania — the smallest of all continents.
While the fallouts from global warming can be many, such as rising temperatures and migration, another case in point the study observes is food security.
Climate change has already created a scenario where heat and humidity have become too severe for humans to tolerate.
Over 150 billion work hours were lost in 2018 due to extreme temperatures, according to The Lancet. As the world experiences global warming, work hours lost to extreme temperatures could double and quadruple depending on how many people would be involved in rural agriculture, affecting productivity and food security.
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