People running and screaming in despair as a wall of sand advances and covers entire towns. Large cities darkening at 3 pm due to smoke produced by a fire thousands of kilometers away.
The scenes recorded during a sandstorm in the interior of São Paulo, in September this year, and after a fire in the Amazon caused particles and smoke to reach cities like São Paulo and Curitiba, a year earlier, are a reflection of climate change and the increase temperatures in the world, according to meteorologists and climate scientists interviewed by BBC News Brasil.
Francisco de Assis, from the National Institute of Meteorology (Inmet), says that the strong storms, gusts of wind and extreme drought recorded in recent years in Brazil are also demonstrations that the planet has warmed up in recent decades.
“Several phenomena that have happened since the 2000s in Brazil are associated with the high variation in the climate resulting from the warming that the Earth is going through”, says the meteorologist.
“Increased storms, strong winds, tornadoes. There are also the most prolonged droughts, in 2001 in the Southeast region, in 2014/2015 and now again, in 2020/2021. If it weren’t for the thermoelectric plants, we would have been without energy. “
In 2020, Cuiabá, capital of Mato Grosso, registered the highest temperature in over a hundred years: 42.7ºC, according to measurement by Inmet.
In October 2020, the state of São Paulo registered the highest increase in history. It was in the city of Lins, in the west of São Paulo, where Inmet recorded 43.5ºC.
Assis explains that changes in temperature cause high rainfall irregularity. This causes more precipitation to occur in some places and less in others.
This is caused, he says, by atmospheric blockages that generate changes in the winds at higher altitudes.
Assis states that these changes are caused both by seasonal natural factors and human influence, due to the burning of fossil fuels.
“This had a direct impact, for example, on summer people [períodos de estiagem na estação chuvosa]. They lasted from 10 to 15 days, but today it reaches 30 days without rain in January and February, impacting the level of reservoirs and crops,” he says.
Carlos Nobre, climate scientist, also credits the rise in global temperatures for the atypical phenomena that have been witnessed.
“We saw extreme heat waves and droughts, like the one from 2012 to 2018 — the longest in the Northeast. Floods, which happened every 20 years, we had in 2009, 2012 and 2021. Not to mention the record level of the Rio Negro, in Amazonas , due to the intense rain records”, he explains to BBC News Brasil.
In June of this year, the Rio Negro had its biggest flood in the entire historical record, beginning in 1902.
Nobre explains that rising temperatures cause an imbalance in rainfall.
“This happens because the water vapor rises, the atmosphere becomes more vaporous, droplets form and it rains. Today, with 1.5ºC to 2ºC warmer, the drought is even more severe and the rain, too,” he says .
He explains that heat also causes more evaporation and hangovers become even stronger. Storms generated in the seas become more intense and cause large ocean waves.
desertification
Meteorologist Francisco de Assis stated that another factor caused by climate change in Brazil is the desertification of some regions.
A BBC News Brasil report pointed out that this process already encompasses an area equivalent to England, in the Northeast and in the north of Minas Gerais.
A report released in August by the Intergovernmental Panel on Climate Change (IPCC), an agency of the United Nations (UN), points out that Brazil is home to one of the areas of the world where climate change has had the most drastic effects: the semiarid.
According to the document, because of climate change, the region —which encompasses a good part of the Northeast and the north of Minas Gerais— has already faced more intense droughts and higher temperatures than usual.
These conditions, together with the advance of deforestation in the region, tend to aggravate desertification.
Assis says it is not possible to say that changes in temperatures are seasonal or not.
“It’s not possible to know if this is a cycle because we only have 150 years of observation on Earth. Thirty years ago it was colder, and now it’s got hot and hasn’t come back. The actual measurement of thermometers is only 180 years. Before that, there were just not so precise studies, made from carbon, simulated and paleontological,” stated the meteorologist from Inmet.
Drilling
Carlos Nobre claims that the only two records of hurricanes in Brazil were the Catarina, which hit Santa Catarina in 2004, and another recorded in 2019 in Espírito Santo and southern Bahia, but which remained in the ocean.
He explains that this type of phenomenon happens when the temperature of the sea water is above 27°C and the wind has no shear — changes in wind directions and speeds — up to a height of 10 km.
“The Catarina was formed at the end of March 2004, when the water was at 26.5°C, something atypical, but there was no shear. Due to a situation of low pressure, it acquired characteristics of a hurricane”, details Nobre.
For Nobre, the water will heat up in the coming years, but “it is still a question whether there will be more hurricanes in Brazil”.
“There is no doubt that this has to do with climate change. We have seen heat records in the Southeast, in Latin America and throughout the Southern Hemisphere,” he says.
dust storm
A meteorologist with over 35 years of experience, Assis said he does not remember any record of a dust storm like the one that occurred this year in cities in the interior of São Paulo.
“This phenomenon happened because we have been without rain for a long time, and this causes dryness and low humidity. When the first storms began in the region, gusts of cold and dry wind were registered. When it joined the dust with the gust of wind, it caused that storm of sand that darkened everything,” he says.
The specialist says that this phenomenon was already common in the region at the end of the driest periods, but with a lower intensity.
For Nobre, the city of São Paulo should be an example for Brazil of how urbanization influences the increase in temperatures and what can happen if deforestation and increased pollution are replicated in other regions.
“The largest city in Latin America is São Paulo, which has heated between 3.5ºC and 4ºC since 1950, becoming an urban heat island. Concrete, asphalt and the lack of vegetation absorb heat and cause extreme rains, as the breeze ascends the Serra do Mar and, upon reaching the plateau, it finds this region with warmer air. The steam rises faster, generating more intense clouds and with more volume of water,” he explains.
For the climate scientist, COP26, the ongoing global climate conference in Scotland, needs to be a turning point to reduce the emission of greenhouse gases and decrease the use of coal and fossil fuels.
“As we have seen in numerous studies, we had a 1.1°C rise in the planet’s temperature and we are already seeing these extreme situations, such as heat waves, storms, landslides, crop failures and forest fires. if the temperature increases by 1.5ºC, there will be even more consequences”, says Nobre.
According to him, pollutant emissions will increase at least until 2023. The ideal, in the scientist’s view, is for countries, especially the most polluting ones, such as the United States and China, to commit to drastically reduce pollutant emissions.
“At least until 2023, they will increase. The cement, steel and agriculture industries are expanding. But countries should set a target to reduce it by 50% by 2030. It is a big challenge, but a COP can be useful for major environmental agreements,” he argues.
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