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Denis Farrell
Scientists sound the alarm with a worrying study: 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 is above 29 degrees Celsius. This places them outside the climatic niche in which humans have lived for at least 6,000 years, scientists around Marten Scheffer of Wageningen University in the Netherlands report in the “Proceedings” of the US National Academy of Sciences. . USA (PNAS).
“The corona virus 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 is quoted in a statement from his university and other research institutions. involved. Changes would occur less quickly, but unlike the current pandemic, no relief can be expected in the foreseeable future.
A look at the past and the future.
On the one hand, Scheffer and his colleagues analyzed the past for their analysis. 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. This distribution has barely changed in the last 6,000 years, which is why researchers call this temperature range the “ecological niche for humans”.
Looking to the future, the scientists used a climate forecast from the IPCC 5th Assessment Report. The concentration of greenhouse gases is supposed to develop largely uncontrollably as in recent decades. Temperatures will rise accordingly in different regions of the world. The researchers also used the SSP 3 socio-economic scenario for world population development.
Migration is not mandatory due to heat.
Model calculations showed that areas with an average annual temperature of over 29 degrees Celsius will now expand from 0.8 percent of the world’s land surface (especially in the Sahara) to 19 percent by 2070. The 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.
“This would not only have a devastating direct impact, but would also make it difficult for societies to face future crises like new pandemics,” emphasizes Scheffer. Such temperature increases did not necessarily mean that people would migrate from the affected areas; because there is a complex set of reasons for migration. However, Scheffer sees the study results as a call to the global community to quickly reduce carbon dioxide (CO2) emissions. (SDA)
