Brazil’s new government, led by President Jair Bolsonaro, has quickly taken steps to loosen environmental law enforcement. Now a review paper shows that the deforestation that could result may have terrible consequences for the Amazon rainforest, including dramatic biodiversity loss, intensified dry seasons, droughts, all ultimately leading to a “state of collapse”.
Scientists worldwide say Bolsonaro’s stance on science and the environment is worrying. He promotes development at all costs and has threatened to follow US President Donald Trump and pull Brazil out of the 2015 Paris agreement.
During the election campaign, he made no secret of his desire to open indigenous lands to mining, farming and dam building, even though about 13 per cent of Brazilian territory is recognised as indigenous lands and protected by law.
Now a review by the climatologist José Marengo, from the National Centre for Monitoring and Early Warning of Natural Disasters, and his colleagues draws together a broad set of data on the Amazon climate to analyse, among other things, the probable effects of large-scale deforestation.
Marengo says that studies recently begun to suggest that Amazon deforestation could reach a tipping point beyond which the ecosystem could collapse. “The combined effects of drought and deforestation, along with fire, might amplify impacts and potentially cause the collapse of the rainforest ecosystem,” he says.
About 19 per cent of the Brazilian rainforest that existed in 1970 has already been cut down. One study from 2018 suggested the tipping point could be as low as 25 per cent deforestation. “If this tipping point is crossed, part of forest might be converted into a savannah,” says Marengo. “It would potentially have large-scale impacts on climate, biodiversity, and the people living there.”
Extreme climatic events, such as droughts, floods, changes in the rainy and dry seasons, and forest fires could also increase, he says.
Scientists already consider the Amazon rainforest to be at great risk of deforestation because of expanding land use for agriculture, which is also one of the main driving forces for climate change in the region.
Deforestation rates could now further be amplified if President Bolsonaro implements his anti-environment agenda, which among other things would allow remote parts of the Amazon to lose their legal protection and become open for use by agribusiness.
Luiz Antonio Martinelli, an ecologist at the University of Sao Paulo, says Marengo’s work is robust and gathers a considerable number of studies that help to better understand how the Amazon rainforest might respond to environment pressures triggered by the new government’s agenda.
Researchers have already observed the lengthening of the dry season over the southern Amazon, which may influence the risk of fire and rainfall regime over the Caribbean and northern South America. This would be especially harmful for the Amazon rainforest, since the impacts of deforestation are greater under drought conditions because fires set for forest clearance might get out of control.
“Efforts to preserve the Amazon rainforest and keep its ecosystems running require a great amount of financial resources and international cooperation,” says Marengo.
But Bolsonaro’s actions have already been controversial on the global stage. On 12 December, during a Facebook-Live session, he announced Brazil could not afford to meet some of the requirements in the 2015 Paris Agreement, and that he was willing to withdraw from it if they were not changed — although he has since backpedalled on the threat.
And less than a month after winning the country’s presidential election, he has also declined to host the UN Convention on Climate Change in 2019 “due to budget restrictions”.
The decision was a blow to global efforts to mitigate global warming because Brazil used to be a key player in such efforts. By refusing to host the UN meeting, the country has sent an important signal.
“Bolsonaro’s government is being quite irresponsible by taking forward an anti-environmental agenda when we already have a substantial mass of scientific evidence indicating that it might destroy Amazon rainforest,” says Martinelli.
He says environmental issues are being ignored as Brazil struggles to escape from its worst ever recession, which has left almost 13 million people unemployed. He says the “government ought to be concerned about economic issues without letting environmental conservation [take] second place”.
Martinelli expects that research will raise awareness of the risks facing the Amazon in other countries and non-governmental organisations that can add pressure on the Brazilian government to change course.
The study published in Frontiers in Earth Science was supported by FAPESP, a donor of SciDev.Net.
This article has been produced by SciDev.Net's Latin America & Caribbean desk.
- Brazil’s new president has already moved to relax protections for the Amazon
= If deforestation increases by just a little, a tipping could be reached
- Beyond this point the Amazon could be converted to savannah