third of the world’s population at risk by 2100

Climate change is making human habitats increasingly uninhabitable. If global warming continues at the current rate, by the end of the century a third of all people could be living in regions outside the human climatic niche. What is meant is a temperature range with an annual mean temperature of 11 to 15 degrees Celsius, in which people have lived for thousands of years. In plain language, this means that for more and more people around the world, it will get hotter and hotter in the coming years. This scenario describes a studywhich was published on Monday in the specialist magazine “Nature Sustainability”.

More than 600 million people worldwide already live outside the climatic niche. That’s nine percent of the world’s population. The research team’s forecast assumes global warming of 2.7 degrees – which is to be expected with current climate policy – and a population growth to 9.5 billion people by 2070 with subsequent decline. A particularly large number of people would then be affected by temperature extremes in India, Nigeria and Indonesia. Large parts of Burkina Faso, Mali and Qatar would also lie almost completely outside the climatic niche.

The number of climate refugees is increasing

For Lisa Schipper, the study results do not come as a surprise: “The idea that fewer and fewer people will be able to lead a decent life is directly related to the IPCC warning (of the Intergovernmental Panel on Climate Change, d. editor) that the time window for securing a sustainable life worth living for everyone is closing,” said the professor of development geography from the Institute of Geography at the Rheinische Friedrich-Wilhelms University in Bonn. Above all, however, climate change affects low-income countries where people are unable to adapt to rising temperatures. Mainly because they don’t have the financial resources to install cooling air conditioning systems, for example.

How can these people protect themselves from the consequences of climate change?

The obvious solution is: you could move to cooler places. To places that are still within the human climatic niche. Because even with global warming of 2.7 degrees Celsius, the earth will not automatically become uninhabitable everywhere. According to the researchers’ simulations, countries in the Global North, such as Europe or North America, would continue to offer relatively good living conditions.

“The study results should not be interpreted to mean that climate change is triggering a mass exodus in places where most or all people live outside the human climatic niche,” Schipper said. So far, most climate refugees have moved within their own country or to neighboring countries. So far, there are no signs that more and more people will soon be fleeing from rising temperatures to Europe, for example. “[Die Studienergebnisse] but it should also not be taken to mean that all people outside of this niche can adapt – because our ability to adapt is significantly reduced with increasing global warming.”

Why too high temperatures are problematic

The study once again confirms that climate change is causing a great deal of human suffering. The hotter it gets on earth, the more problems there are. Droughts, crop failures, water shortages, species extinction, resource conflicts – to name just a few. Health problems are also part of this: heat has been proven to cause cardiovascular problems, can lead to heat stroke and limit performance. For the elderly and sick, heat can even be deadly. This means that the higher the temperatures rise, the more dangerous they become for humans.

However, heat alone is not the reason why regions become uninhabitable. Even in areas within the human climatic niche where temperatures are tolerable, living conditions can deteriorate—for example, when droughts occur that make agriculture impossible. Or when floods occur and sea levels rise. So the ideal ecological niche for humans includes not only the right temperature, but also factors such as humidity, water availability and geographic conditions for effective farming.

The effect of the 1.5 degree mark

In the view of the authors of the study, one thing is particularly important in order to maintain the ecological niches for humans: limiting global warming. If the global temperature were reduced from 2.7 to 1.5 degrees Celsius, five times fewer people would be exposed to dangerous heat by the end of the century. The researchers also calculated that 350 million fewer people would be affected for every 0.3 degrees of temperature increase avoided.

“We’re already seeing the effects of dangerous heat on people in different parts of the world,” said Wendy Broadgate, executive director of the Earth Commission, a global consortium of scientists involved in the study. “This will only accelerate if we don’t act immediately and decisively to reduce greenhouse gas emissions.”