BRASILIA (REUTERS) - Dry weather this year raises the risk of severe fires in Brazil's Amazon rainforest and Pantanal wetlands, scientists say, warning that a drought could fuel destruction of biomes critical to curbing climate change.
Last year, dry weather helped fuel record fires in the Pantanal, while the Amazon experienced the worst rash of blazes since 2017, according to Brazil's national space research institute INPE.
This year's rainy season - running roughly from November to April next year - was even drier in parts of the Amazon under greatest threat, known as the "arc of deforestation", INPE data show.
This year's drought in the Pantanal is more severe and widespread than what the region saw in 2020, the data show.
"The rainy season is already finished and it was a bad rainy season," said Mr Marcelo Seluchi, a meteorologist in the Science Ministry's disaster monitoring centre. "The fire season will probably be bad."
Fires and deforestation in the Amazon rainforest have surged since right-wing President Jair Bolsonaro took power in 2019, calling for more development in the region.
Environmental advocates say that Mr Bolsonaro's rhetoric and weakening of environmental enforcement has emboldened criminals to fell trees and set fires to stake illegal claims to public lands.
The Amazon is the world's largest rainforest, and the Pantanal is the biggest wetland. Scientists say their preservation is vital to curbing catastrophic climate change because of the vast amounts of greenhouse gas they absorb.
The forecast in the next few months is for continued dryness south of the Amazon river, said Dr Renata Libonati, a remote-sensing specialist at the Federal University of Rio de Janeiro.
"Any ignition has a high chance of setting off big fires that run out of control," Dr Libonati said.
While those vulnerable regions experience less rainfall than usual, the northern Amazon basin is flooding due to heavy rains.
That phenomenon is in line with the extreme wetness and dryness that scientists expect to see more frequently due to climate change, said Dr Maria Silva Dias, an atmospheric scientist at the University of Sao Paulo.
More extreme weather in the Amazon is linked in part with a warming in the tropical North Atlantic over the last 20 years, leading to stronger winds and shifts in atmospheric circulation, Dr Dias said.
She and other scientists cautioned that no one knows for sure how much climate change is contributing to the changes in weather patterns. "This is an open question and still one that we worry about," she said.
Climate change is likely one of several factors affecting weather, along with Amazon deforestation shifting regional rain patterns and existing long-term cycles in weather.
While dry weather provides fuel, humans provide the spark.
Naturally occurring fires, caused by lightning for example, are extremely rare in the lush rainforest.
Fires in the Amazon are usually started by farmers renewing fields or ranchers and speculators illegally clearing land.
Environmental advocates say Mr Bolsonaro has given many people the impression they will not be punished for setting fires.
"What's happening is that people feel that nothing is going to happen to them if they burn, and then they burn," said Dr Dias. "It's not just climate... it all depends on the law being enforced."