In 2024, an alarming milestone was reached: global temperature surpassed the 1.5-degree Celsius limit for the first time, as defined in the Paris Climate Agreement, signed in 2015, with the aim of preventing catastrophic climate changes for the planet and its populations. The recorded increase was 1.6 degrees Celsius relative to pre-industrial temperature levels, measured between 1850 and 1900. Although this number may seem small in absolute terms, the consequences of this temperature rise are immense, not only for the environment but also for human health. The report released by the Copernicus Climate Change Service (C3S) on January 10, 2024, issued a global warning about the far-reaching impacts of this shift, which directly affects ecosystems, climate patterns, and, inevitably, populations around the world.
Environmental health expert Helena Ribeiro, professor at the Department of Environmental Health at the School of Public Health of the University of São Paulo (FSP-USP), explains that the 1.6-degree Celsius increase in global temperature may not have immediately visible impacts for all individuals, but climate change brings transformations that directly affect human well-being by altering the balance of ecosystems and the functioning of the planet. The warming of the Earth is resulting in more intense and frequent climate extremes, such as unbearable heatwaves, intense cold, torrential rains, prolonged droughts, and even violent storms. These phenomena affect natural climate patterns and have direct consequences on the health of populations.
These climate changes cause imbalances in natural systems, generating extreme heatwaves, with temperatures that may exceed 40°C in some regions, and cold waves, with temperatures that can drop to dangerously low levels in others. According to Professor Helena Ribeiro, these thermal extremes, although they may seem distant from our everyday experience, have profound effects on the human body, especially for vulnerable groups such as the elderly, children, pregnant women, people with preexisting diseases, and individuals with low immunity.
Heatwaves, for example, can have a devastating impact on the cardiorespiratory system. Excessive heat can lead to dehydration, exhaustion, sunburn, and even heatstroke, a condition where the body cannot regulate its internal temperature and can lead to death. Furthermore, these high temperatures worsen cardiovascular diseases, such as heart attacks, and respiratory diseases, such as asthma and bronchitis, due to air pollution, which intensifies with the heat.
On the other hand, cold waves have an equally damaging effect, as the rapid cooling of the body makes it harder for blood circulation, which can overload the heart and cause circulatory complications. The cold is also directly associated with an increase in respiratory diseases, such as flu, pneumonia, bronchiolitis, and even severe lung infections. For populations already weakened by circulatory and respiratory issues, the impact of extreme cold can be fatal. The expert emphasizes that these conditions can lead to an increase in emergency medical visits, hospitalizations, and even deaths, especially among the elderly and children, who have weaker immune systems.
These thermal extremes, both heat and cold, not only affect individual health but also place immense pressure on public health systems. With the increase in climate-related diseases, such as cardiovascular, respiratory, and dehydration-related illnesses, hospitals and clinics become overwhelmed. The increase in demand for medical care during extreme weather events can result in a collapse of the healthcare system, especially in regions with inadequate medical infrastructure.
Moreover, these impacts are not distributed equitably. Low-income populations are the most affected, as they often live in more vulnerable conditions, with inadequate housing, lack of access to healthy food, drinking water, and quality healthcare services. The lack of access to appropriate cooling or heating technologies and difficulty accessing medical services worsen the situation for these populations, making them more susceptible to serious illnesses and health complications.
Climate change will exacerbate social and economic inequalities, as the poorest and most marginalized populations have less capacity to adapt to the new challenges posed by extreme weather conditions. For these people, the increase in global temperature represents an increased risk not only to health but also to food and water security, as prolonged droughts and floods can affect food production and the availability of drinking water, essential factors for survival.
Brazil, as a tropical country, is particularly vulnerable to the effects of the temperature increase. IPCC projections indicate that countries located in tropical regions, such as Brazil, will experience a higher temperature increase than temperate regions, making them even more exposed to extreme weather phenomena. Excessive heat and water scarcity may become more frequent, further aggravating living conditions in both urban and rural areas.
However, the tropical climate also has its advantages, such as summer rains, which help reduce temperature through cloud cover and precipitation. Nonetheless, climate change is transforming these weather patterns, making rains more unpredictable and intense, with longer dry periods. This climatic instability puts agriculture, the health of the population, and the country’s water resources at risk.
Moreover, studies conducted in various Brazilian regions, including São Paulo and Paraná, have shown that intense cold waves can also harm health, with an increase in hospitalizations and deaths, especially among the elderly and children. This highlights that climate change will not only affect rising temperatures but will also bring consequences for colder regions, further challenging the population’s adaptation capacity.
Another important aspect is the behavior of vectors of infectious diseases. With the rise in global temperature, the environment becomes more favorable to the proliferation of mosquitoes that transmit diseases like dengue, zika, and chikungunya. The expansion of areas where these mosquitoes can live and reproduce is a growing concern, as diseases once more restricted to tropical regions can now spread to more temperate areas.
High temperatures accelerate the life cycle of these mosquitoes and increase the likelihood of outbreaks of diseases transmitted by them. Controlling these epidemics involves not only the use of pesticides but also public policies aimed at eliminating mosquito breeding grounds and controlling standing water. However, the indiscriminate use of pesticides can cause additional environmental problems, such as the resistance of vectors and the negative impact on local biodiversity.
Although the challenges are immense, there are several ways to mitigate the effects of temperature rise on human health. The installation of tents and cooling spaces in urban areas, distribution of drinking water during extreme heat, and creation of emergency care points are immediate measures that can reduce health damage.
Additionally, long-term actions are essential for adapting cities and populations to climate change. Large-scale tree planting, creation of urban green spaces, forest restoration, and promotion of sustainable agricultural practices can help reduce local temperatures, improve air quality, and promote public health. Creating public policies that encourage the use of renewable energy, the construction of more resilient infrastructure, and the promotion of environmental education are crucial to effectively addressing the issue.
According to Professor Ribeiro, to limit the impacts of global warming, immediate and coordinated actions must be taken. Controlling greenhouse gas emissions and pollutants, shifting to renewable energy sources, and promoting reforestation policies are key to reducing the impact of climate change. Measures such as restoring degraded pastures and reducing meat consumption also contribute to mitigating the effects of global warming.
Public health will be one of the main fields affected by climate change, and it is essential that governments, international organizations, businesses, and individuals join forces to implement effective solutions to reduce health risks. The future of the planet depends on our ability to act collaboratively and urgently to face this global challenge.
