After months of successive temperature records around the world, a new heat wave has been punishing Brazilians. Situations like the one recorded in Rio de Janeiro this Tuesday (14), where the thermal sensation reached 58.5°C in the west of the city, should be increasingly frequent in the future.
The scenarios outlined by scientists for the country on a planet that is warming — due to greenhouse gas emissions from human activities — are longer periods of hotter and drier weather, in addition to higher temperatures.
“Brazil, as a tropical region and a country very vulnerable to climate change, will suffer more from the increase in temperature”, points out Paulo Artaxo, physicist at USP and member of the IPCC (Intergovernmental Panel on Climate Change), linked to the UN.
“IPCC forecasts suggest that Brazil’s temperature, according to the emissions scenario, could increase, on average, by around 4°C”, says the researcher.
Artaxo highlights the UN panel of scientists’ prediction for a 3°C increase in temperature, which is what is projected if there is no drastic cut in emissions. “A climate event that occurred once every 50 years will occur 39 times every 50 years and will be 5 times more intense,” he says.
He also points out that this forecast is especially worrying for tropical countries, which already have higher temperatures than the rest of the globe.
“This will impact the health of the population and the functioning of ecosystems [no Brasil] much more than countries like Sweden or Norway”, he explains. “Can you imagine the impact of an increase of 3°C to 4°C in a region, for example, like Teresina, Cuiabá or Palmas?”
Speaking about the intense heat that hits the country this year, the physicist states that it is possible to point to two factors as the main culprits: global warming, which increases the frequency of extreme weather events, and El Niño – which, in turn, it is worsened and becomes more frequent with the increase in sea surface temperatures caused by climate change.
El Niño is caused by the warming of the tropical Pacific Ocean (in the Equator region) and increases temperatures, especially in the North and Northeast regions of the country. Even though meteorologists know that the phenomenon is one of the culprits for the current heat wave, it is important to remember that for some parts of Brazil, such as the Southeast and Central-West, the behavior of El Niño does not always translate into heat.
“What we are seeing is the future of the country’s climate, and the country, obviously, has to prepare better to face these heat waves”, warns Artaxo.
According to Inmet (National Institute of Meteorology), this is the eighth time that a heat wave has hit the country this year alone.
A study on the heat of August and September, which caused the temperature to reach 41.8°C in Cuiabá and 43.5°C in São Romão (MG), showed that climate change increased the chance of extreme heat like this occurs. El Niño, they assessed, had a small contribution during that period.
Without global warming caused by humans — essentially associated with the burning of fossil fuels, but also with actions such as deforestation — the heat at the end of winter and beginning of spring in Brazil would have been 1.4°C to up to 4 .3°C lower, according to the work.
The analysis was carried out by WWA (World Weather Attribution), which studies the causes of climate events, and included the participation of Lincoln Alves, a researcher at Inpe (National Institute for Space Research).
He explains that it is not entirely possible to apply the results found in the study to the current phenomenon, as it was done based on the conditions found at that previous moment.
“[Mas,] In general, what has been observed in different regions of the world and in Brazil is that heat waves are closely related to climate change and global warming”, he adds.
He stresses that there has been an increase in the number and intensity of hot spells in recent decades and that this is a strong sign of the climate crisis. A survey by Inpe (National Institute for Space Research) released this Monday (13) showed that, in 30 years, heat waves in Brazil increased from 7 to 52 days a year.
In addition to environmental and socioeconomic impacts, extreme heat has a direct impact on people’s health, which can lead to cardiovascular, respiratory and kidney problems.
Climate ‘new normal’?
Different research centers point out that it is practically certain that 2023 will be the hottest year in 125 thousand years, following several other index records in the last two decades.
Thus, many wonder if this scenario is the climate “new normal”.
“We cannot call a climate like the one we have now ‘normal’. This is a totally anomalous situation, with very pronounced warming and which has a very large socioeconomic impact. But what we are currently seeing, in 2023, is a free sample of what could happen over the next few decades”, says Artaxo.
“Climate models have always predicted an increase in global temperatures, but we are seeing that the reality of climate change is even stronger than the models predicted.”
Alves also points out that, compared to previous decades, the climate is no longer the same. “The climatic conditions, the average temperatures, the volume of rain, the intensity of the rains, all of this has changed. The seasons have become increasingly hotter”, says the Inpe researcher.
The perception that 2023 could be the coldest of future years, if there is not a substantial cut in the amount of carbon released into the atmosphere, is shared by scientists around the world.
“Unless we turn off the tap on greenhouse gas emissions into the atmosphere, 2023 will feel cold when we are in 2033 or 2043,” said Samantha Burgess, deputy director of the Climate Change Service at the European observatory Copernicus, when July 2023 was announced as the hottest month ever recorded in history.
“We need to take ambitious climate action to cut emissions, stabilize our climate and ensure it remains livable not just for people, but for all the ecosystems around the world that we depend on,” he added.