Heat Waves in the Northern Hemisphere Highlight the Health Impacts of Climate Change

The impact of climate change is already a reality and its effects have become increasingly intensified. The month of July highlighted this process very clearly with the heat wave that hit a series of countries on three continents: Europe, Asia and North America. 

According to the European observatory Copernicus, July was the hottest month ever recorded in the history of the planet, surpassing the last world record of 2019 by 0.33ºC. With this intensification, the UN Secretary-General, António Guterres, states that the world has surpassed the level of warming, reaching a state of “global boiling”. 

“The Earth’s atmosphere is gaining a greater amount of energy and one of the ways the climate system dissipates this energy is through an increase in extreme weather events”, explains Paulo Artaxo, professor in the Department of Applied Physics at the Institute of Physics at USP. 

This episode not only impacted nature, but also seriously affected the health of the population in these regions with temperatures above 30ºC. Paulo Saldiva, professor at the Department of Pathology at the Faculty of Medicine at USP, explains that thinking about climate change together with health can encourage changes in behavior. 

Furthermore, there is an unequal impact on the health and life of society, since the poorest and most peripheral populations are more vulnerable to climate change. Helena Ribeiro, professor at the Department of Environmental Health at the Faculty of Public Health at USP, calls the phenomenon climate injustice. 

Biological reaction

The comfort and thermal preparation zone varies according to each country and each region within the country. Saldiva places each of these populations on a scale of ideal temperature and extremes of hot and cold – which cause an increase in mortality –, beyond the adaptation capacity of each country. “New York, for example, is more prepared for the cold than for the heat. There is also an acclimatization process within the same country; in São Paulo, thermal discomfort begins when the temperature rises above 26 degrees, which is the perfect comfort zone for Teresina”, explains the professor. 

The moment climatic conditions go beyond the human being’s predisposition to adapt, the organism starts to react and become ill. Contrary to common sense, Saldiva emphasizes that hypothermia and hyperthermia do not summarize or predominate the causes of death in extreme temperatures, they represent the absolute minority. 

In most cases, patients die from natural causes triggered by a variety of health complications. For example, kidney failure or urinary tract infections caused by dehydration, as well as cardiac consequences caused by intense vasodilation and overload of the heart. Thus, professor Helena Ribeiro points out the elderly, children and pregnant women as the most vulnerable, in addition to people who already have chronic health comorbidities. “In social terms, people with lower incomes are often the most affected, as they live in areas at greater risk of floods and landslides, more polluted and with less urban forestry”, points out Helena.

Brazilian forecasts

As it is a tropical country and is already within the temperature limits, Artaxo comments that Brazil is becoming even more fragile to climate change. In regions like Teresina, where thermometers can already reach 40ºC during the summer, highs of up to 48ºC are expected and serious consequences for the health of the population, according to Artaxo. 

Helena reveals that Brazil is more sensitive to cold waves than heat, considering that, unlike the Mediterranean climate of southern Europe and the western United States, the country’s tropical climate has rainy summers that mitigate the phenomenon. In addition, there are some cultural adaptations, such as light clothing and frequency of bathing. 

However, the professor highlights the lack of infrastructure still faced by the health system to offer air-conditioned environments for both professionals in the field and patients. “The Brazilian system is already quite overloaded and if there is a worsening of heat waves, it will be necessary to train health personnel”, highlights Helena. 

Actions

Saldiva states that prevention activities at the primary care level are central to preparing the health system in the face of environmental conditions, in order to transmit warnings to the population. “Look at the weather forecast, they say if you will have to take an umbrella for the day, but there is no health forecast”, compares the professor to demonstrate the importance of a prevention policy. 

The direct relationship between climate change and human health can bring a new point of view to facing and raising awareness of this global crisis, in Saldiva’s opinion. With individual health and that of loved ones at stake, the professor reflects on the greatest impact on the population’s consumption habits and profiles.