We are currently heading towards a warming of 2.7 degrees Celsius. In India, Nigeria and Indonesia, most people will be affected by extreme heat.
Current policy will lead to a global warming of 2.7 degrees Celsius by the year 2100. A third of the world’s population would have to live in temperatures unusual for human existence, reports a research team with Austrian participation in the journal “Nature Sustainability”. If the temperature rises to 1.5 degrees Celsius, 14% will be affected. To date, 600 million people have been forced out of the “human climate niche” by climate change.
The research team led by Timothy Lenton of the University of Exeter (Great Britain) defined the temperature range in which most people lived in the past as a “human climate niche”. For example, livestock can be raised there and useful plants can sprout. Caroline Zimm of the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, near Vienna, also took part in the study.
The “habitability” of the earth will fundamentally change
Under different climate scenarios, the researchers examined how many people will live in regions with temperatures beyond this human climate niche at the next turn of the century. With the temperature increase currently most likely (another 2.7 degrees Celsius on the global average), that would be a third of the predicted nine billion people inhabiting the Earth.
The chances of meeting the 1.5 degree threshold are slim given the continued rise in greenhouse gas emissions. Indeed, Earth is currently heading towards 2.7 degrees of warming, and this will fundamentally change Earth’s “habitability” and potentially lead to “a large-scale reorganization of the places where people live,” said lead author Lenton.
increase in diseases
For every additional 0.1 degree rise in temperature, “another 140 million people will be exposed to dangerous heat,” added Lenton. The countries with the most people at risk of dangerous heat, according to the study, are India (600 million people), Nigeria (300 million people) and Indonesia (100 million people).
On the other hand, if the trend were positive for every 0.3 degree Celsius of temperature rise avoided, 350 million fewer people would be affected. If the Paris Agreement target of limiting warming to 1.5 degrees Celsius were reached, it would be “only” 14 percent. Living outside the “human climate niche” would mean increased disease and mortality, they explain.
The study authors define an average temperature of 29 degrees as dangerous heat. The risk is particularly great in the hot and humid regions along the equator: there, heat can be fatal even at low temperatures, because the body cannot cool down by evaporating sweat from the skin when humidity is high.
(APA/AFP)