Aerial views show houses destroyed by fires in the surroundings of the SP-330 highway in Ribeirao Preto, Sao Paulo state, Brazil on August 25, 2024. Days after Brazilians sweltered under scorching heat, panted through a parching drought, and choked from wildfire smoke, temperatures continued to linger between 35º C and 40º C (95º F to 104º F) throughout the week. These blistering temperatures are primarily affecting the Central West region, which includes large cities like Brasília, Manaus, and Belo Horizonte.
In addition to putting residents of these areas at risk of heat stroke and other health problems, the escalating heat has increased the risk of wildfires. In recent weeks, blazes exacerbated by climate change have consumed large sections of the Amazon rainforest, Pantanal wetlands, and Cerrado savanna, as well as the southern state of São Paulo. Residents have reported coughing and gagging on the smoke, experiencing shortness of breath, and suffering from eye pain due to irritants in the air.
On Sunday, the Brazilian government released data showing that the number of August wildfires in Brazil was the highest recorded since 2010. These heat waves and wildfires are a direct result of anthropogenic global warming. Dr.
Michael E. Mann, a professor of Earth and Environmental Science at the University of Pennsylvania, stated: “It’s a ‘new abnormal’ and it is now playing out in real time — the impacts of climate change are upon us in the form of unprecedented, dangerous extreme weather events. And it will only get worse as long as we continue to burn fossil fuels and generate carbon pollution.”
Thick gray smoke emanates from fires burning in Brazil and Bolivia.
Wildfires exacerbate Brazilian heat waves
High temperatures, low humidity, and extended drought throughout both countries are exacerbating the fires. The ongoing fires are adding to environmental stress in the region, posing risks to both ecosystems and human health due to the substantial smoke and associated particulate matter.
Ultrafine particles (UFPs) in wildfire smoke can significantly impact air quality, human health, and the environment, extending far beyond the immediate vicinity of the fires. These tiny particles can travel long distances, spreading their effects over vast regions. Emerging research indicates that ultrafine particles are more resilient and influential than previously thought, suggesting their impact on climate and weather patterns might be far more significant than earlier assumptions.
This challenges traditional views on how wildfire smoke interacts with the atmosphere and calls for a deeper investigation into the role of ultrafine particles in environmental processes. A team of researchers from the Pacific Northwest National Laboratory (PNNL), in collaboration with their partners using the specialized G-1 research aircraft, conducted comprehensive measurements and advanced model simulations to analyze ultrafine particles in detail. The study revealed that UFPs were not only present but also highly abundant in smoke from vegetation, with specific atmospheric conditions favoring their formation, persistence, and survival.
The research significantly enhances our understanding of how aerosols produced by vegetation fires can influence weather patterns, cloud dynamics, and long-term climate change, underscoring the need to incorporate ultrafine particles into Earth system models. To understand how both ultrafine and larger particles influence cloud formation and precipitation, the team employed particle size data and hygroscopicity profiles generated by the WRF-Chem model, combined with a sophisticated cloud microphysics framework known as WRF with spectral bin cloud microphysics. The simulations revealed that while ultrafine particles have the potential to strengthen storms, enlarge storm anvils, and lead to more intense rainfall, the presence of larger particles from fires tends to delay precipitation onset and reduce rainfall intensity.
Overall, this research highlights the necessity for more detailed consideration of ultrafine particles in climate and weather prediction models, with significant implications for understanding the broader impacts of wildfire smoke on our environment.
