Survival and climate change: Scientists identify 'deadly' heat and humidity combo

The Earth is heating up, and soon it may reach temperatures and humidity that after a few hours of exposure could prove fatal for humans, even young ones. Based on recent research, scientists have identified the maximum mix of heat and humidity a human body can take.

Wet bulb temperature

Previously scientists thought that a young, healthy person will die after enduring around six hours of temperatures close to 35 degree Celsius (95 degree Fahrenheit), and 100 per cent humidity. However, new research argues that the actual threshold could be much lower.

Researchers at United States' Pennsylvania State University decided to put the theorised "wet bulb temperature" to the test — the point at which sweat no longer evaporates off the skin, leading to heatstroke and eventually death. This was earlier measured using wet cloth and thermometers.

Measuring the core temperatures of healthy, young people inside a heat chamber, researchers found that the study participants reached their "critical environmental limit" at a wet bulb temperature of 30.6 degree Celsius, much lower than previously theorised.

Climate change and temperature rise

The previously thought heat, humidity-bearing capacity of humans (35 degrees Celsius) as per an AFP report has only been breached a few times, particularly in South Asia and the Persian Gulf. 

Climate change, however, is leading to an increase in dangerous wet bulb events, with the frequency of such events doubling over the past 40 years, said Colin Raymond of NASA's Jet Propulsion Laboratory while talking to AFP.

Raymond's research indicates that if the world warms 2.5 degrees above pre-industrial levels, these wet bulb events will get even more frequent.

A recent report by European Union's climate change service Copernicus shows that oceans have hit their hottest-ever recorded temperature. Beating a 2016 record, the daily global sea surface temperatures have reached 20.96C, which is far above the average for this time of the year, reports BBC. In 2016, a record was set when the naturally occurring El Niño was in full swing.

Experts warn that extreme heat events, even below the 35-degree limit, can be deadly. They say that different people have different thresholds based on factors such as age, health, and even socioeconomic conditions. They point out that people least able to protect themselves from extreme heat will suffer the most.