We have often spoken in this journal about what is called the phenomenon of the "wet thermometer" ; that moment when climatic conditions make human life impossible.
As a reminder, the wet thermometer, transcribed Tw in English, is the climatic phenomenon in which the temperature exceeds 35 ° C and the humidity level is equal to or greater than 90%. According to scientists, the human being cannot survive for long at 35 degrees TW since a body cannot lose heat if this outside temperature TW exceeds its own, scientists then agree that the human being cannot survive for long at 35 degrees TW. "After half a dozen hours, in the absence of artificial cooling, this will lead to organ failure and death," said Colin Raymon, researcher at NASA and lead author of a study dating from May 2020. In practice, the body can no longer cool itself down. In a context of dry or not very humid air, the sweat evaporates and the body thus manages to refresh itself and to maintain the 37 °. In a situation of excessive humidity, sweat no longer evaporates and the body overheats. Dr Laurent Uzan, sports cardiologist at France 2, explains that at this time: “The temperature inside starts to rise, […] we can start to have vision problems, dizziness, disturbances neurological, it can end in coma, convulsions, and it can lead to serious cardiac or renal complications ”.
Climatologists and researchers have known about the phenomenon of "wet heat wave" for some time now. And many are those who have planned the first manifestations for 2050. That left us about thirty years. But it looks like we won't have them. Indeed, in an IPCC (Intergovernmental Panel on Climate Change) report published on August 9, experts report that two regions of the world are now too hot and humid for humans to live there: Ras Al Khaimah in the United Arab Emirates, in the Persian Gulf and Jakobabad in Pakistan.
The tipping point has just occurred in two regions of the world 30 years ahead of schedule. And there is little doubt that other regions will follow, such as China or much of India. The most threatened are the tropics and coastal areas, where the high temperatures add to the evaporation from the sea.
This is very bad news and a most worrying signal which adds to the urgency to act and reduce our greenhouse gas emissions.