As the Amazon burns at a rate higher than any year measured since 2010, the environmental crisis is being watched closely by researchers in Boulder, who have devoted years of study to the long-term implications of degradation to the planet’s forests, critical for their capacity to store carbon dioxide.
This month alone, more than 26,000 forest fires, the most in a decade, have been recorded in the Amazon rainforest, which not only captures global-warming CO2, but is an important habitat for endangered species and home to indigenous people.
According to the New York Times, Brazil’s National Institute for Space Research reported Wednesday its satellite imagery had detected 39,194 fires this year in the world’s largest rain forest, which is a 77% increase from the same point in 2018.
The Amazon has often been referred to as the Earth’s “lungs,” because they both release oxygen but also store carbon dioxide, a significant contributor to global warming. A major loss of rain forest leads to an increase in savanna, which doesn’t store as much carbon.
Jennifer Balch, director of the University of Colorado Boulder’s Earth Lab, has been conducting research on the dynamics of fire in the Amazon since 2004, as part of a team of researchers that includes scientists from the Woods Hole Research Center, the Amazon Environmental Research Institute and the Max Planck Institute for Biogeochemistry.
The objective, she said, was “to test where the limit is for the Amazon forest, and where is the tipping point?”
‘New type of grassland’
The Amazon Burn Experiment saw scientists establish a 370-acre plot in the southeastern portion of the Amazon in the state of Mato Grosso, a state larger than Texas in west-central Brazil, mostly covered with Amazon rainforest, wetlands and savanna plains.
“We were working on three 50-hectare plots, which are a kilometer by a half-kilometer, and in this experiment, we burned one every year, and burned one every three years (to mimic the natural El Niño cycle) and left the control unburned, to see how the burned were doing compared to the intact forest,” Balch said. “From seedlings to adult trees, we have been measuring and monitoring that forest for over a decade.
“The upshot of a decade or more of work is that we could convert this forest into a new type of grassland, through a decade of multiple burns and against a backdrop of increasing temperatures. Drought and fire, combined, can shift the Amazon forest into a new type of grassland. This is not a projection to 2050. This is happening right now.”
Balch, also an associate professor in geography and fellow at Boulder’s Cooperative Institute for Research in Environmental Sciences, said the experimental burns stopped in 2010, but the project continues, with monitoring the forest system’s recovery, from seedling to mature trees.
“The question shifted from okay, now that it converts to grassland, now what happens? And we have not seen the forest recover the diversity of species that were there before. Essentially what we have is a couple of scrappy tree species — we call those pioneer species. They can come in where it’s really hot and dry, and they just go gangbusters,” Balch said.
“But we’ve lost a lot of the diversity of this forest, and so we’re monitoring the forest system to see how it’s going to recover, once it’s past its tipping point. And so far we have not seen it go back to what it once was.”
She said that while a person on a hike in Boulder County’s foothills might expect to typically see about four different tree species, the area in which her group’s studies features about 100. There are places in the Amazon where the number is double or triple that, she said.
Massive burning of the Amazon is hardly new. During the 1997-98 El Niño season that caused a significant drought in the Amazon, 39,000 square kilometers burned, roughly three times the size of Connecticut. What has changed since then is two more decades of additional warming. And Brazil since last year is now led by President Jair Bolsonaro, who has been accused of emboldening farmers’ loggers’ and miners’ encroachment on the rainforest, in support of that nation’s economy but to the detriment of the national and even global ecology.
“There has been a lot of released incentive to deforest, and put in soy and cattle pastures,” Balch said.
“What we’re concerned about as a scientific community, Brazilian, Germans, Americans, is that we can see the Amazon burning from space, and we know what it’s indicating is the backdrop of a warming climate, emissions from land use, and the fragmentation of those forests. Those three things are combining to make the forest really vulnerable to transition, and shifting to a new state.”
Concern in the global community was spiked this week when Bolsonaro first rejected the pledge of $22 million on international aid proferred at the recent Group of 7 summit, saying other nations should keep their noses out of Brazil’s affairs, then became embroiled in a personal feud with French President Emmanuel Macron. He subsequently accepted $12 million in British aid.
“In the U.S. we spend 2-to- $3 billion a year fighting wildfires. and that (rejected) aid package is around $22 million,” Balch said. “So, what would be required to solve that problem is on an order of magnitude greater than what’s been put on the table.”
‘Fighting about it’ no solution
At Boulder’s National Center for Atmospheric Research, senior scientist David Edwards has been engaged for nearly 30 years in satellite remote sensing of atmospheric composition, and for 20 years has been associated with NASA’s Terra Measurements of Pollution in the Troposphere satellite project. In that capacity, he has been measuring and tracking the smoke plumes from the Amazon fires — and of late, large fires that are now ablaze in central and southern Africa as well as Siberia.
“We were actually some of the very first people to map these plumes, starting two decades ago,” Edwards said. While Amazonian fires are nothing new, he said the Brazlian fires, most of which are started by humans, have drawn more attention this year as heavily populated coastal cities such São Paulo have been enshrouded in orange haze.
“Especially because of the new government in Brazil, the question, is have the changes in policy resulted in more deforestation happening this year than in previous years? It’s important to note, it’s not as if this is the first time this has happened,” Edwards said. “The question is, how much more forest is being cut down, how much of it is the clearing of the land, and how much is burning of land that has already been cleared?”
Many scientists prefer to stick to their data and avoid discussions of policy. Edwards appeared to choose his words carefully.
“As scientists, we in general would want to be preserving the tropical rain forest to the extent possible,” Edwards said. “Just as they’re important repositories of carbon, if that goes into the atmosphere it’s definitely going to exacerbate climate change and make it harder to reach climate goals, and preserve biodiversity and natural habitat.”
To the extent that conservation priorities can be elevated to the policy level, he said, “l think that would be to everybody’s interests.”
Balch addded, “My take on this is that we as scientists need to put our heads together, and we as nations have to put our heads together to solve the Amazon fire problem. There is no way we’re going to get to a solution if we’re fighting about it.”