Historic Amazon rainforest fires threaten climate and raise risk of new diseases

01 October 2020

Published by https://theconversation.com/

BRAZIL – The fires in the Amazon region in 2019 were unprecedented in their destruction. Thousands of fires had burned more than 7,600 square kilometres by October that year. In 2020, things are no better and, in all likelihood, may be worse.

According to the Global Fire Emissions Database project run by NASA, fires in the Amazon in 2020 surpassed those of 2019. In fact, 2020’s fires have been the worst since at least 2012, when the satellite was first operated. The number of fires burning the Brazilian Amazon increased 28 per cent in July 2020 over the previous year, and the fires in the first week of September are double those in 2019, according to INPE, Brazil’s national research space agency.

Despite the surge in fires, international attention has waned in 2020, likely due to the COVID-19 pandemic. Yet the degradation of the Amazon rainforest has profound consequences from climate change to global health.

Global climate implications

The Amazon rainforest covers approximately eight million square kilometres — an area larger than Australia — and is home to an astounding amount of biodiversity.

It helps balance the global carbon budget by absorbing carbon dioxide from the atmosphere, and plays a key role in the global water cycle, stabilizing global climate and rainfall. A nine nation network of Indigenous territories and natural areas have protected a massive amount of biodiversity and primary forest.

Yet these lands are under siege. As of 2019, an estimated 17 per cent of the Amazon’s forest cover has been clear-cut or burned since the 1970s, when regular measurements began and the Amazon was closer to intact.

As the rainforest bleeds biomass through deforestation, it loses its ability to capture carbon from the atmosphere and releases carbon through combustion. If the annual fires burning the Amazon are not curtailed, one of the world’s largest carbon sinks will progressively devolve into a carbon faucet, releasing more carbon dioxide than it sequesters.

While the global impacts are dire, the local impacts of these fires are also significant. Persistent poor air quality, which extends far into Brazil and other regions of South America, including in metropolitan centres like São Paulo, can lead to health problems.

As roads are built and forests are cleared for timber production and agriculture, a checkerboard of tropical forest edges is created. These destructive activities can lead to rapid extinctions and a severe loss of species richness anywhere that human encroachment occurs.

Many researchers predict that deforestation is propelling the Amazon towards a tipping point, beyond which it will gradually transform into a semi-arid savanna. If the deforestation of the rainforest continues past a threshold of 20-25 per cent total deforestation, multiple positive feedback loops will spark the desertification of the Amazon Basin.

Global health implications

Zoonotic diseases, like SARS-CoV-2, the virus that causes COVID-19, are on the rise. Understanding the root causes of these spillover events that move viruses from animals to humans gives us insight into how to prevent future zoonotic outbreaks. The degradation and fragmentation of tropical rainforests such as the Amazon may be a key factor in this process.

The checkerboard of forest edges increases the potential points of contact between humans and wildlife, which in turn increases the likelihood of viral transmission and the emergence of novel human diseases. Intact forests and high levels of biodiversity, on the other hand, can provide a “dilution effect

Print Friendly, PDF & Email
WP-Backgrounds Lite by InoPlugs Web Design and Juwelier Schönmann 1010 Wien