How hot is it?

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The recent floods in Germany and other Central European countries, as well as the favorable weather conditions in Sardinia, are considered to be part of one of the most complex climatic events under long-term study and analysis by scientists. Frequent disturbing reactions in public opinion. There are considerable opinions in the scientific community Climate change It is somehow linked to the high frequency of extreme weather events such as hurricanes, floods and droughts.

Not only is it a factor associated with these phenomena, but the increase in global average temperature – associated with an increase in greenhouse gases in the atmosphere – often creates extreme conditions and severe effects even during heat waves, even at maximum temperatures above 40 degrees. At the end of June, at least 6,500 people They are dead Due to the heat wave that has been hotter in India than in the last nine years. Hundreds of people at the same time and for the same reason They are dead In western Canada and the northwestern United States. One of the cities most affected by the heat wave – Portland, Oregon – is the most deadly in Maltnoma County. Lack Air conditioning or fans.

– Also read: Floods in Europe are associated with climate change

Recent heat waves, reflecting the site Stone slab Yes it is Asked In the “Future Dense” section – he works with General Policies, Emerging Communities and Technologies, Arizona State University – the extent to which human habitats in some of the most populous areas are currently warming up. First he mentions the difference between dry heat and humid heat, a difference that is well known and frequent even in common texts (even if it creates a very popular clich: “It’s not heat, it’s humidity”).

An air-conditioned hospitality center was set up at the Oregon Convention Center in Portland on June 27, 2021 (Nathan Howard / Getty Images)

Palm Springs is a popular Southern California resort city, famous for its luxury hotels, golf courses and cultural events. Yet it is located in the desert a few hours by car from Death Valley, one of the most famous places. Hospitality Of the United States. With enough water to avoid sunlight – and in shady places – for example, humans can survive for hours in the heat of Palm Springs, with a maximum temperature of up to 50 degrees, in hot and dry climates.

Things change completely when you move from a place like Palm Springs to one of the humid parts of Palm Beach, Florida, the Western Hemisphere. A day with 50 degrees can cause thousands of deaths from hyperthermia, which is characterized by a rapid increase in body temperature, which is common in environments with high temperature, high humidity and poor ventilation. Prolonged exposure to these types of conditions can cause a change in the body’s normal thermoregulation mechanisms by preventing the spread of heat caused by sweat.

– Also read: Everything about sweat

To better describe hyperthermia and understand the concept of “the basis for survival and mitigation of climate crisis”, according to Stone slab, It is useful to recall the concept of wet bulb temperature, a value different from the temperature of a dry bulb – measured by a common thermometer – and usually measured by a thermometer wrapped around a piece of wet ghee. Due to the cooling effect of water evaporation, the temperature measured by a thermometer covered with a damp cloth in a given environment is lower than the temperature of a dry bulb in the same environment. The difference between the two temperatures is similar to one of the humidity measurements: at 100 percent humidity, a lot simplifies, the temperature of the dry and wet bulb is the same.

Sarajevo, Bosnia, 23 Jujno 2021 (AB Photo / Kemal Softik)

And Believes Deadly changes in normal human thermoregulation can occur in environments with wet bulb temperatures above 35 degrees (but with values ​​lower than this, depending on other variables). When it is hot outside and our bodies are sweating, he explains Stone slab, Energy is needed to convert sweat from fluid in the skin to vapor in the air, and that energy comes from body heat, which cools through this process and avoids an increase in internal temperature.

Dry heat is a very tolerable condition because evaporation occurs so quickly that we do not even notice sweat on the skin. This is also the reason why dehydration is a very definite risk in desert ecosystems, where dry air is allowed to withstand heat but in the meantime includes continuous loss of fluids. In the presence of very high temperatures and air saturated with water vapor, sweat remains on the skin and body heat cannot be released. If the outside temperature exceeds a certain limit, a condition that causes death within a few hours, the internal temperature rises and begins to approach the outside until a dangerous equilibrium is reached.

– Also read: What exactly is “perceived temperature”

Perception of the temperature of the wet bulb Considered A very important parameter would be useful to monitor the effects of climate change and to have accurate indications of when and where cities will become uninhabitable. In fact, it refers to conditions that humans cannot imagine considering their basic physiological limitations. Gradually increase the size of the world population by accessingAir conditioningAside from having a large cost in terms of the environment, this is not considered a long-term solution to the problem, and an increase in demand will increase the probability of interruptions in the power supply.

Outside rain on Thursday, July 1, 2021 in Baghdad, Iraq (AB Photo / Khalid Mohammed)

The most shared climate models indicate that heat waves will be frequent and very intense in large parts of the planet, with significant effects in early 2050. Although predicting the course of moisture is a very complex process, it is Provides In fact, the temperature increase will affect both the dry bulb and the wet bulb temperature, resulting in insufficient shade and hydration to survive. According to these forecasts, the most vulnerable areas to frequent uninhabited danger in the United States will not be the current high-temperature desert, but already humid areas such as the Midwest and East.

Extreme heat waves with a bulb temperature of more than 35 degrees Celsius, according to other climate models They will be Regular and increasingly common in the Persian Gulf, the Indian subcontinent and the regions of eastern China, in the most populous areas of the world.

– Also read: Climate will trigger the largest migrations

Many predictions They point out It is necessary to reduce greenhouse gas emissions as quickly as possible or to reduce global warming as much as possible or how many times these extreme heat waves are expected to occur in the future. They also underscore the need to implement policies to protect the most vulnerable population, including the creation of air-conditioned centers for elderly residents and the timely issuance of preventive warnings in the event of immediate heat waves.