One-third of Earth's land will become uninhabitable: who will lose their home?

Scientists have been warning for years about the looming climate crisis facing the planet: as a result, the world has already experienced unprecedented heatwaves and droughts, but researchers believe conditions may worsen. If humanity succeeds in achieving the climate target set by the Paris Agreement, by the end of this century, people will live in a world that is on average 2 degrees Celsius warmer compared to pre-industrial times. Unfortunately, this will lead to a reduction in the areas on the planet where humans can survive, according to Science Alert.

Observations indicate that the global average temperature has already risen by 1.5°C compared to pre-industrial levels — a grim milestone humanity reached just last year. Now, scientists believe that a further increase of 0.5°C will triple the land area that will become too hot for human survival. For comparison, this area is comparable to the size of the United States.

The results suggest that for individuals over 60 years old, whose bodies are even more vulnerable to extreme heat, this dangerous zone will encompass about 35% of land, significantly higher than the current figure of 21%.

According to co-author of the study, climatologist Tom Matthews from King’s College London, the findings of the new research are extremely important and highlight what we need to prepare for, as these projections are based on a more moderate scenario of global warming.

With a warming of about 4°C above pre-industrial levels, unbearable heat for adults will affect around 40% of land area. The results also indicate that only high latitudes and cooler regions of the mid-latitudes will remain untouched.

Even at peak health, our bodies can only handle a certain amount of stress, which can be quite problematic. However, there is "uncompensable" heat, where more heat enters your body than its temperature-regulating mechanisms can manage. This is an issue faced by people in extremely hot conditions, often exacerbated by personal protective equipment: for example, firefighters and athletes. Yet, it is becoming increasingly common during periods of intense heat, particularly in equatorial regions.

The authors of the study note that residents of certain regions of the Earth have already begun to feel the effects of climate change. In recent years, areas such as the Persian/Gulf, the Indo-Gangetic Plain, and even isolated hotspots in the southern United States, Mexico, and Australia have experienced extreme heatwaves. All these incredible temperatures pose a danger even to young and healthy individuals.

There is also intolerable heat that can essentially be fatal. During the study, scientists defined this threshold as an internal body temperature of 42°C for six hours or less. The results indicate that with a global temperature rise of 2°C above pre-industrial levels, unsustainable heat thresholds in certain regions will be breached for people over 60 years old.

However, if humanity fails to reduce greenhouse gas emissions, and the average Earth temperature rises by 4-5°C, in some regions, the heat will reach dangerous levels for people of all ages.

Adults over 60 may experience intolerable heat on 60% of the Earth's surface, while unsustainable heat becomes a risk for individuals of any age in the tropics, where currently more than 40% of the global population resides.