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If greenhouse gas emissions are not reduced, 3.5 billion people could suffer extreme heat in 50 years. They would live in areas where the average annual temperature exceeds 29 degrees Celsius, if they do not migrate. This is what researchers Marten Scheffer of Wageningen University in the Netherlands predict in the journal “Proceedings of the National Academy of Sciences”.
“The coronavirus has changed the world in a way that was difficult to imagine just a few months ago, and our results show how climate change could do something similar,” Scheffer said. Changes would occur less quickly, but unlike the current pandemic, no relief can be expected in the foreseeable future.
For their analysis, the researchers initially looked at the past:
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Using existing databases, they compared people’s preferred settlement areas with the climatic conditions in these regions. They found a peak in population density at average annual temperatures of around 11 to 15 degrees Celsius and a smaller peak of 20 to 25 degrees Celsius.
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This distribution has hardly changed in the last 6000 years, which is why the team calls this temperature range the “ecological niche for humans”.
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To classify: According to the German Meteorological Service (DWD), the average temperature in Germany in 2019 was 10.3 degrees Celsius. It currently increases by 0.37 degrees Celsius in Germany every decade.
The team also looked to the future:
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The researchers were only slightly optimistic. In their work, they assume that there is no international climate protection and that the concentration of greenhouse gases will develop largely without control, as in previous decades. This is an assumption that you can at least argue about. In the most recent IPCC assessment report, this extreme scenario is just one of many. The increase in temperature in the different regions of the world is, of course, particularly strong.
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Model calculations showed that areas with an annual average temperature of more than 29 degrees Celsius, now 0.8 percent of the global land surface, currently the areas are mainly in the Sahara, will expand to 19 percent for 2070.
The additional areas were mainly in South America, Africa, India, Southeast Asia, and Northern Australia. It would affect more than a billion people in India alone, and more than 100 million people in Nigeria, Pakistan, Indonesia and Sudan.
Complex set of reasons responsible for migration
Such warming “would not only have devastating direct effects, but would also be more difficult for societies to face future crises like new pandemics,” Scheffer said. The anticipated temperature increases did not necessarily mean that people would actually migrate from the affected areas. There is a complex set of reasons for migration, according to the researchers.
However, Scheffer sees the results of the study as a call to the global community to quickly reduce carbon dioxide emissions. So there is no extreme scenario.
