A new report has identified 27 ways a heatwave can cause human death. And, if we keep up with our fossil fuel fondness, up to 75 per cent of humanity may at risk of one of those 27 outcomes.
[Camilo Mora of the University of Hawaii] and colleagues report in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes that they worked through the medical literature to discover in as much detail, and in as many ways as possible, how heat can kill a warm-blooded mammal equipped by evolution to maintain a constant body temperature of 37°C in normal conditions.
“We know of many cases where people have died as a result of heatwaves. However, why people died is a question whose answer is scattered”, Dr Mora said.
Their study focussed on seven vital organs – heart, brain, intestines, kidneys, liver, lungs and pancreas – and five physiological mechanisms triggered by heat: for the medically-minded, these are ischaemia, heat cytotoxicity, inflammatory response, disseminated intravascular coagulation and rhabdomyolysis.
That meant 35 possible combinations, and of these, they found 27 different pathways in which extreme heat could lead to organ failure and then death. Any one of these, or a combination, could kill.
Dr Mora and his colleagues have already warned that lethal heat waves will become a more frequent hazard: by 2100, if humans go on burning fossil fuels under the notorious business-as-usual scenario, 75% of us could be at risk. He has also warned that climate change could be happening faster than many researchers expected and that rising temperatures could actually reduce harvests, especially in the tropics.
The story goes on with really grisly details of what can go wrong within the human body. If you want that detail use the first link at the top.
