With climate change comes a series of unfortunate consequences, and rising temperatures are at the top of the list. This phenomenon is particularly dangerous for areas near the equator as the rapidly increasing heat threatens to make these regions literally uninhabitable. The latest research has announced that rising temperatures and humidity are pushing tropical areas to the limits of human adaptation, to the point of lethality.
The human ability to regulate our core temperature of 37 °C depends on the surrounding air temperature and humidity, together known as the wet-bulb temperature. This should not exceed 35 °C, otherwise our skin would not be able to cool itself and keep the heat away from the inner body. Without this, the resulting conditions could be deadly.
Researcher Yi Zhang from Princeton University, leader of this new study published in Nature Geoscience, explains that humidity is crucial for survival in a warm climate. When it is too humid, sweat is unable to evaporate from our skin to cool us down. He says, “High body core temperatures are dangerous or even lethal.”
Zhang’s research team has worked out how much wet-bulb temperature will alter as the global temperature continues to rise. The key conclusion is that temperature extremes are increasing along with the mean temperature in tropical areas. As such, the temperature should not be rising by more than 1.5 °C to ensure that wet-bulb temperatures in the tropics will not pass 35 °C.
This may sound manageable at the outset, but the reality begs otherwise. The same study claims that the tropics would suffer from fatal consequences even before the temperature hits the 1.5 °C limit. In fact, even a 1 °C rise in wet-bulb temperature is thought to potentially cause negative health impacts on humans.
As of today, the planet is seeing an average of 1.1 °C temperature increase due to human activities and global warming. While multiple nations involved in the Paris climate agreement had agreed to try and prevent this number from increasing, scientists have concluded that it would not remain so after a decade.
This study is only the most recent addition to a range of scientific research imposed on the dangers of rising heat. Heatwaves could render certain Middle Eastern, Chinese and Indian regions unlivable. Additionally, we have seen twice the amount of fatal heat and humidity levels between 1979 and 2017. Indeed, this is not good news for any of us, considering that 40% of the world’s people currently reside in the tropics. This statistic is foreseen to hit 50% by 2050 largely due to the younger populations in these regions.
If global governments fail to limit the rise in temperature to 1.5 °C as compared to the pre-industrial world, regions around the equator will soon risk being entirely uninhabitable by the human population. Indeed, one should not place their hopes on the human ability to adapt in the short term, as the study reports the condition will be beyond ‘the limit of human adaptation’.