The world is getting warmer, which threatens the possibility of living in many regions around the equator.
At this point, even if we manage to limit global warming to 2°C above pre-industrial levels, new estimates suggest that tropical and subtropical regions, including India, the Arabian Peninsula and sub-Saharan Africa, will experience extremely dangerous temperatures in most World Days in 2100.
Meanwhile, the world's mid-latitudes will experience extreme heat waves at least every year. In Chicago, in the US, for example, researchers expect a 16-fold increase in dangerous heat waves by the end of the century.
Researchers say the world will exceed 2 degrees Celsius of warming by 2050.
In this case, the researchers say, "extremely dangerous heat stress would be a regular feature of the climate in sub-Saharan Africa, parts of the Arabian Peninsula, and much of the Indian subcontinent."
Unless the world can work together to implement rapid and large-scale adaptation measures, there are likely to be many deaths. But every bit we can lower temperatures still matters, because every bit of a lower temperature would save lives.
Recent estimates indicate that global warming is already responsible for one in three heat-related deaths globally.
Based on these rates, other studies predict that people will die in record numbers in the coming decades as climate change tightens its grip on our planet.
However, how humans deal with heat stress is complicated by other factors, such as humidity. Current estimates are based on a scale known as the heat index, which takes into account relative humidity up to certain temperatures.
This is the traditional measurement that researchers use to measure heat stress, however recent studies have found that the human body may not be able to handle as much heat and humidity as this indicator indicates.
As it stands, 93 degrees Celsius (200 degrees Fahrenheit) on the heat index is a survivable ceiling.
But at 100% humidity, new research suggests that even healthy, young people may not exceed 31°C.
However, in the traditional heat index, temperatures are considered dangerous when they exceed 40 °C (103 °F) and extremely dangerous when they exceed 51 °C.
These are the thresholds the current study used to predict future housing potential, and there's a good chance you're underestimating what's to come.
However, even by this scale, humanity's prospects look dire.
Between 1979 and 1998, the hazardous heat index threshold was exceeded in the tropics and subtropics on 15% of the days each year.
During this time, it was rare for temperatures to become too dangerous according to the heat index. Unfortunately, the same cannot be said for today, and the problem is getting worse.
By 2050, in the tropics, the dangerous heat index could be exceeded on 50% of the days each year. By 2100, it can be exceeded on most days.
What's more, about 25% of those days can be extremely hot, and they can cross very dangerous thresholds.
It is possible that without significant emissions reductions, large parts of the global tropics and subtropics will experience heat index levels above what is considered 'dangerous' for the majority of the year by the end of the century. Without adaptation measures, this would lead to a significant increase in disease incidence. heat associated and reduced ability to work outdoors in many areas where subsistence farming is important."
There is no doubt that the health and societal consequences will be profound.” Science Alert