Guest essay by Eric Worrall
According to New Scientist, places which can’t afford air conditioning are in real trouble.
Climate change has already made parts of the world too hot for humans
Global warming has already made parts of the world hotter than the human body can withstand, decades earlier than climate models expected this to happen.
Wet bulb temperature (TW) is a measure of heat and humidity, taken from a thermometer covered in a water-soaked cloth. Beyond a threshold of 35°C TW the body is unable to cool itself by sweating, but lower levels can still be deadly, as was seen in the 2003 European heatwave that killed thousands without passing 28°C TW.
“The crossings of all of these thresholds imply greater risk to human health – we can say we are universally creeping close to this magic threshold of 35°C. The tantalising conclusion is it looks like, in some cases for a brief period of the day, we have exceeded this value,” says Tom Matthews at Loughborough University in the UK.
Clare Heaviside at University College London says the work is broadly in line with existing research, but cautioned against the focus on the threshold of 35°C TW. “It is difficult to link a wet bulb temperature threshold to specific health outcomes, and for different population groups,” she says.
…Read more: https://www.newscientist.com/article/2242855-climate-change-has-already-made-parts-of-the-world-too-hot-for-humans/
The abstract of the study;
The emergence of heat and humidity too severe for human tolerance
See all authors and affiliationsScience Advances 08 May 2020:
Vol. 6, no. 19, eaaw1838
Humans’ ability to efficiently shed heat has enabled us to range over every continent, but a wet-bulb temperature (TW) of 35°C marks our upper physiological limit, and much lower values have serious health and productivity impacts. Climate models project the first 35°C TW occurrences by the mid-21st century. However, a comprehensive evaluation of weather station data shows that some coastal subtropical locations have already reported a TW of 35°C and that extreme humid heat overall has more than doubled in frequency since 1979. Recent exceedances of 35°C in global maximum sea surface temperature provide further support for the validity of these dangerously high TW values. We find the most extreme humid heat is highly localized in both space and time and is correspondingly substantially underestimated in reanalysis products. Our findings thus underscore the serious challenge posed by humid heat that is more intense than previously reported and increasingly severe.Read more: https://advances.sciencemag.org/content/6/19/eaaw1838
“It is difficult to link a wet bulb temperature threshold to specific health outcomes, and for different population groups,”
Smart advice. Hard wet bulb limits are the fantasy invention of people who have worked all their lives in comfortable air conditioned offices in temperate countries.
A long time ago I had job operating a hydraulic hot press in a poorly ventilated chemical factory. On the very hottest days the indoor temperature hit 55C / 130F, according to the thermometer next to my station, with visible lingering clouds of mostly water steam from polymerisation of the material being pressed.
The management used to look concerned when temperatures peaked, made sure we drank a cup of rehydration fluid every 5 minutes, but otherwise we just carried on.
Plenty of blue collar workers, such as miners, bakers and foundry workers, endure similar conditions on a regular basis.