While Italy and other European countries are grappling with the problems created by excessive temperatures, in the Indian subcontinent the effects seem more mitigated.
People continue to die of heat, but do they die less? And if so, for what reason? Accounts are wrong or we are facing a new trend of humanity, more resilient in the face of extreme phenomena caused by climate change? These are some of the questions that David Wallace-Wells tries to answer, in an article published in the New York Times.
War Bulletin
Here and in Europe the hot emergency now a war bulletin: an African anticyclone is coming for at least 10 days, which will bring more heat and drought to the bitter end. France and Spain are burning and the fires are counted no more. In the United Kingdom An amber alarm was issued for the prediction of record temperatures, up to 40 degrees centigrade. An exceptional situation complete with a meeting of the Cobra (Cabinet Office Briefing Rooms), the coordination and strategy committee of the British government set up to respond to a national or regional crisis. On the other side of the globe, however, the monsoon season has arrived. A moment that allows us to take stock of the consequences of the waves of heat that hit South Asia in extraordinary succession starting this spring.
The situation in India
From late March to late June, a period of almost 100 days, the punitive heat spread over much of the Indian subcontinent, often covering more than a billion people and in some places exceeding 50 degrees (Celsius) . In May, the World Weather Attribution Initiative, a research alliance linking extreme events to global warming in real time, said the initial wave had been made 30 times more likely by climate change. According to scientists, the maximum survival limit for humans occurs when the combination of heat and humidity produces what is called a wet bulb temperature of 35 degrees Celsius for six hours. Above that level, it is believed that exposure would also kill young and healthy people.
According to the NYT report, however, a first estimate of the death toll of only 90 in India and Pakistan, a fraction of the more than 1,000 people killed by the heat wave that hit the Pacific Northwest (including western Canada) last summer, where cooler temperatures hit millions for a much shorter period of time. an even smaller fraction of the number of deaths in the heatwaves of 2003 and 2010 in Europe and Russia, which killed 70,000 and 55,000 people respectively. In those heat waves, only a handful of places exceeded 40 degrees.
How our body reacts to heat
Why so few people died (but definitive data are still missing), in the face of such high temperatures lasted for much longer than the canonical six days indicated by science as the maximum tolerable limit for man? What is happening? To try to understand this, we must first make a premise and explain human physiology. The theme is basically this: the high temperature becomes dangerous when there is high humidity. If the humidity is relatively low and there is a minimum of ventilation in the room where the heat wave occurs, the health risk is much lower because human thermoregulation allows you to be able to pass unscathed even a certain number of consecutive days of high temperatures, explains the professor Alessandro Miani president of the Italian Society of Environmental Medicine (Sima).
This is because l
sweating our first form to regulate the internal temperature. So if there is a low relative humidity and we manage to sweat, our sweat has time to evaporate and therefore to steal heat from the human body, being able to keep all the main vital functions active. If there is wind, this facilitates the evaporation of sweat. If, on the other hand, the relative humidity rate is very high, this mechanism tends to not work or to work much slower leading to very serious situations that can lead to death. This regardless of any area of the world, adds the expert.
The five hypotheses
So far the mechanisms that regulate man’s response to exceptional heat. But what are the explanations for the phenomenon which, if confirmed by epidemiological data, could throw new light on the relationship between man and climate change? Five are hypothesized on the Nyt: problems with data; dry heat wave; the role of cultural practices and adaptation; the hottest parts of the world may already be relatively acclimatized to extreme heat; i
Our casual use of wet bulb temperature readings can be misleading with respect to the actual risk of mortality.
The data problem
Let’s start from the first hypothesis: in reality the deaths recorded in India and Pakistan are underestimated. This is certain, we also see it now, for example with Covid. The certainty of the data depends on the level of preparation and collection capacity also of epidemiology centers who are able to recognize a death for a certain cause or are reported as death perhaps for other causes – explains Miani -. So often the deaths attributable to these phenomena do not pass as deaths due to the heat, but to other pathologies therefore they are not marked with a certain attribution. a predominantly cultural question of preparation and also of capillarity of the health service in a country and of cultural preparation to understand that a collapse, a heart attack rather than another cause of death is attributable to high temperatures or perhaps to a level of dehydration even small.
Extremely hot, but dry
The second hypothesis instead refers to the greater presence of a dry hot climate. cos: dry heat allows life, humid heat makes it extremely difficult, because the human body cannot have sufficient thermoregulation, emphasizes the president of Sima. Third probable answer, cultural practices and adaptation. Absolutely yes. P.populations that have a life practice or are used to living in conditions of less comfort than us Europeans, certainly have an innate ability to adapt. Could the hottest countries in the world be less vulnerable to heat, relatively speaking? I have some doubts about this, because no
n that the hottest countries in the world must suffer less. Surely a country in which the population accustomed to higher temperatures for centuries have acquired not so much an adaptation – because human adaptation to change is not a matter of hundreds of years but of thousands or tens of thousands of years and unfortunately today the environment runs much faster than our ability to adapt – but more of a cultural issue.
Are we more resistant?
The last hypothesis put forward that the wet bulb temperature parameter to define the limits of human resistance to heat is not so exact. To date, I have not read any articles that are significantly important with respect to the determination of this parameter – Miani answers -. So it probably should be investigated better and perhaps better investigated in countries where science is good for you. In my opinion, the point always remains this: a question related to humidity and ventilation. We can also spend a month or two months or three months at 33 if the weather is dry and there is some ventilation. We think of the nomadic populations living in the desert. My opinion that for this reason it could be a topic that maybe we too could deal with with a research.
The future
How should we behave then in the face of the dangers brought by climate change? Climate change was not born yesterday, we have already seen its effects for seventy years it affects everyone and everything and we must – very quickly without discussing opportunities or not and particular interests or not – abandon the fossil source as quickly as possible because it is the main cause of climate change and rising temperatures, concludes Miani.
July 15, 2022 (change July 15, 2022 | 13:06)
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