It’s no secret that the world’s largest tropical rainforest, the Amazon, is under tremendous pressure, close to an ecological tipping point and in danger of collapsing.
But the situation is far worse than we might realize, according to new research suggesting that the gloomy Amazon’s future has dawned in the wake of unbridled deforestation.
The new research – the most comprehensive assessment of the impact of the Amazon Basin on the world climate to date – has found that the forest with fires, drought and soil clearance releases more gases than it stores in plants and soil.
This means that the Amazon is likely to heat and not cool the Earth’s atmosphere, and that the worrying effect is only expected to grow, says the group of more than 30 scientists behind this work.
Moreover, the jungle can no longer be relied upon to compensate for greenhouse gas emissions from human activities, namely the burning of fossil fuels, which squander our remaining global carbon budget.
What distinguishes this research is that this research, unlike previous studies, magnifies all the global warming gases that come through the Amazon basin and cycle into the atmosphere and assess the direct impact of human activities on one of the largest carbon stores on earth.
“Cut [down] the forest pays attention to its carbon uptake; it’s a problem, “ecologist and lead author Kristofer Covey told Skidmore College in New York National Geographic.
“But if you start looking at these other factors along with CO2, it becomes really hard to see how the net effect is not that the Amazon as a whole is warming the world climate.”
Ecological studies and climate research on the Amazon Basin have generally focused largely on the uptake and storage of CO2 by the forest, and rightly so – CO2 makes up the bulk of human greenhouse gas emissions in the Amazon largely through forests. powered. deterioration.
Forest loss in the Amazon is so severe that some scientists have estimated that the rainforest could go from a carbon tank to a carbon source that releases more CO2 than it could contain in 2035.
Researchers are also concerned that the region is rapidly reaching a disastrous ‘tipping point’ where the Amazon is being pushed to the edge and becoming a very different, much drier ecosystem, with the illegal increase in nationwide activity.
But CO2 is not the only factor influencing the Earth’s climate, nor is the Amazon Basin easy to study, with its mountainous mountain forests, mangrove wetlands and river systems spanning nine countries in South America.
The other two major agents for climate change are nitric oxide (N2O) and methane (CH4). These gases do not last nearly as long in the atmosphere as CO2, but they are much more powerful than greenhouse gases – that is 300 times more heat per molecule than CO2 in the case of N2O.
Globally, emissions of both methane and nitrous oxide have increased significantly over the past decade or two. And now, with this analysis and the image below, we can appreciate how these less studied gases tilt the scale specifically in the Amazon.
(Covey et al., Frontiers in Forests and Global Change, 2021)
Above: Greenhouse gases driving through the Amazon.
Analyzing existing data on greenhouse gas emissions and the combined effects of human impact in the Amazon basin, the researchers showed how the Amazon is likely to exacerbate climate change by emitting more gases than it naturally absorbs.
Never before has a study of the Amazon Basin evaluated data in such a way as to consider the full range of interactions between forest and climate, which the study authors call a “discouraging task” and the central challenge that limits our understanding of the Amazon’s global climate impact.
The ecosystem-wide analysis also goes deep into the granular details, because given how large the Amazon basin is, even seemingly small changes in the amount of greenhouse gases absorbed or released by the forest (and its micro-covered soil) contribute to massive upheavals throughout the ecosystem.
Prolonged droughts reduce the Amazon’s ability to absorb CO2 and increase the chance of wildfires – which burned at a record pace in 2019. Just like the illegal fires that are lit to clear land, these wildfires turn trees into soot particles that absorb sunlight and turn the knob up at atmospheric temperatures.
Meanwhile, deforestation of the industry, which has increased by 60 percent in the Brazilian Amazon since 2012, cleared thousands upon thousands of square kilometers of forest each year for mining and agriculture, breaking up soils, changing rainfall patterns and increasing the amount of sunlight that Amazon reflects in the atmosphere where greenhouse gases await.
Add to this comparison with dam building, mining exploitation, seasonal floods, severe storms, land compaction for fields and grazing cattle – which changes the forest and its emissions – and it is understandable how the researchers could have come to such a disaster. closure.
Admittedly, the team acknowledges a great deal of uncertainty in their results, which they put down due to a lack of data from some parts of the Amazon, especially the meandering river systems, and the unique ecological characteristics of a forest that is so large that it creating its own climate. .
Yet, with the available data, the emerging result of their analysis is that the Amazon releases more heat traps than it stores, creating a net warming effect in the Earth’s atmosphere.
Protecting the Amazon is now more urgent than ever and includes restricting deforestation and restoring the rights of indigenous lands.
The research was published in Boundaries in forests and global change.