Date: 15 May, 2020
Date: (SD): 8 May, 2020
Source: Earth Institute at Columbia University
Summary of ScienceDaily: „A new study has identified thousands of incidents of previously rare or unprecedented extreme heat/humidity combinations in parts of Asia, Africa, Australia, South America and North America, including in the U.S. Gulf Coast region.“
Method of Research
The authors of the study, which appeared last week in the journal Science Advances, analyzed data from weather stations from 1979 to 2017.
Colin Raymond (the lead author of the study) and his colleagues examined the hourly data from 7,877 individual weather stations which allowed them to pinpoint short-lived extreme heat/humidity combinations.
- Repeated incidents appeared in much of India, Bangladesh and Pakistan; northwestern Australia; and along the coasts of the Red Sea and Mexico’s Gulf of California
- The highest, and potentially fatal ones, were discovered 14 times in the cities of Dhahran/Damman, Saudi Arabia; Doha, Qatar; and Ras Al Khaimah, United Arab Emirates (all of them have a – combined – population of over 3 million people)
- Other countries which were hit are South China, subtropical Africa and the Caribbean
- In the US, the Southeast experienced these conditions „dozens of time“, and the worst incidents occured in New Orleans and Biloxi, Miss.
Why is extreme heat/humidity so dangerous?
As the article of Science Daily explains it very well:
„Humidity worsens the effects of heat because humans cool their bodies by sweating; water expelled through the skin removes excess body heat, and when it evaporates, it carries that heat away. The process works nicely in deserts, but less well in humid regions, where the air is already too laden with moisture to take on much more. Evaporation of sweat slows. In the most extreme instances, it could stop.“
One result of long exposure to extreme heat/humidity is organ failure, because the body overheats and without a place to retreat – such as an air-conditioned room – there’s no way to cool down. Even if you are a physically fit and strong, you could only survive for a few hours (given that you have an unlimited supply of water, no clothes on and rests in the shade).
In the US, heat-related illnesses already kill more US residents than any other weather-related hazard including cold, hurricanes or floods. As the graph also shows:
For now, the extreme heat/humidity combination only appears within localized areas, as the article elaborated on earlier: „The outbreaks have so far been confined to localized areas and lasted just hours, but they are increasing in frequency and intensity, say the authors.“
There’s also a reason why previous climate studies have failed to recognize most past incidents: „[…] climate researchers usually look at averages of heat and humidity measured over large areas and over several hours at a time.“
What has been thought to come in one or two decades, may increase quickler – on the basis of the new findings -.
- Rich nations can also be affected economically by it, since the extreme heat/humidity may be forced to stay inside for longer periods of time which could force farming, commerce and other activities to a halt (*similarily to what we experience now with the collapse of economies due to the SARS-CoV-2)
- Poorer countries are at most risk since they do not have electricity (and thus no air conditioning) and rely on subsistence farming which requires daily outdoor heavy labour -> those regions could turn to uninhabitable areas
Addendum 1: *My own assessment at that time given a business-as-usual scenario. However, even under these circumstances, it may greatly vary betwen countries and regions. A temporary halt due to extreme heat (e.g. heatwave) may be more likely than a long-term shutdown in wealthier nations, overall the estimation in the brackets is unreliable and cannot be compared to a global pandemic (added: 11th May, 2021)