A new study has found that more than three billion people could be living in “unlivable” temperatures by 2070. If greenhouse gas emissions are not reduced, large numbers of people will have to live in climates with average temperatures above 29 degrees Celsius. This would represent a significantly different climate than humans have experienced over the past 6,000 years. “This study provides a clearer picture of how climate change affects humans,” said Tim Lenton, co-author of the study.
The study is based on United Nations data on world population and data on the global temperature increase of three degrees Celsius. According to a UN report, even in countries following the Paris Climate Agreement, temperatures are still projected to rise by three degrees Celsius.
The human population will become concentrated in narrow climatic zones, with people tending to live in areas where the average temperature is around 11-15 degrees Celsius. Fewer people will live in regions with an average temperature of 25 degrees Celsius or more, the study reports. Humans have lived in these milder climates for thousands of years. However, a global temperature rise of three degrees Celsius will mean that many people will be forced to live in temperatures outside the “suitable climate.”
Tim Lenton, a climate expert and director of the Global Systems Institute at the University of Exeter, conducted the study in collaboration with scientists from China, the United States, and Europe. The scientists involved in the study shared the following insights:
“The land is warming by more than three degrees because land temperatures are increasing faster than ocean temperatures. Populations are already growing in hot regions like sub-Saharan Africa, meaning many people will have to adapt to an even warmer climate in the future.”
“As human populations grow in warmer areas, their local temperatures will also increase. We find that people in these regions could be facing a temperature increase of 3 degrees Celsius, but locally, it could feel like 7 degrees Celsius.”
“Northern Australia, India, Africa, South America, and parts of the Middle East could be affected more severely. This is because it’s challenging for people in low-income regions to protect themselves from extreme heat.”
“We should not be overly concerned about the wealthy, who can survive in air-conditioned buildings. Instead, we should focus on those who have no way to shield themselves from extreme temperatures and climate conditions.”
According to Tim Lenton, the key message of this study is: “Limiting the human activities that drive climate change brings enormous benefits. This will reduce the number of people projected to live outside suitable climates.”
“Approximately one billion people are affected by each degree Celsius rise in temperature. So if we can prevent even one degree Celsius of warming, we can make a tremendous difference to people’s lives.”
Here is a YouTube video of a discussion of Tim Lenton.