It’s no secret that the world’s largest rainforest, the Amazon, is under immense pressure, on the verge of reaching an ecological investment point and at the risk of collapsing.
But the situation is much worse than we may realize, according to new research suggesting that the bleak future of Amazon has come as a result of rampant deforestation.
The new research, the most comprehensive assessment of the influence of the Amazon Basin on the global climate to date, found that with fires, drought and land clearing, the forest releases more gases that capture the heat it stores in plants and soil.
This means that the Amazon is likely to warm the Earth’s atmosphere and not cool it, and the worrying effect is only expected to grow, according to the group of more than 30 scientists behind this work.
In addition, the jungle can no longer be counted on to help offset greenhouse gas emissions from human activities, namely the burning of fossil fuels, which waste our remaining global carbon budget.
What differentiates this research is that, unlike previous studies, this research adds up all the global warming gases circulating in the Amazon Basin and into the atmosphere and assesses the direct impacts of human activities on one of the largest carbon stores on Earth.
“Tall [down] the forest interferes with its carbon sequestration; that’s a problem, ”said environmentalist and lead author Kristofer Covey at Skidmore College in New York National Geographic.
“But when you start looking at these other factors alongside CO2, it’s very hard to see how the net effect isn’t that the Amazon as a whole is really warming the global climate.”
In general, ecological studies and climate research in the Amazon Basin have focused absolutely on the acquisition and storage of CO2 from the forest, and rightly so: CO2 accounts for most of the gas emissions. of humanity’s greenhouse effect, which in the Amazon are driven mainly by forests. degradation.
The loss of forests in the Amazon is so severe that some scientists have estimated that the rainforest could move from a carbon sink to a carbon source that releases more CO2 than it can contain as soon as 2035.
Researchers are too concerned that, as illegal land-clearing activities increase, the region is rapidly approaching a catastrophic “turning point” where the Amazon is pushed to the limit and becomes a much drier ecosystem .
But CO2 is not the only factor influencing the Earth’s climate, nor is it easy to study the Amazon Basin, with its mountainous mountain forests, mangrove swamps, and river systems straddling nine American countries. of the South.
The other two major agents of climate change are nitrous oxide (N2O) and methane (CH4). These gases do not last nearly as long in the atmosphere as CO2, but they are much more potent than greenhouse gases, trapping 300 times more heat per molecule than CO2, in the case of N2O.
Globally, emissions of both methane and nitrous oxide have increased substantially in the last decade or two. And now, with this analysis and the following graph, we can see how these less studied gases tip the scales in the Amazon, specifically.
(Covey et al., Frontiers in Forests and Global Change, 2021)
Above: greenhouse gases circulating in the Amazon.
Analyzing existing data on greenhouse gas emissions and the combined effects of human impacts across the Amazon Basin, the researchers showed that the Amazon is likely to worsen climate change by emitting more gases than it naturally absorbs.
Never before had a study of the Amazon Basin evaluated the data in such a way that it considered the complete set of forest-climate interactions, what the study’s authors called a “daunting task” and the a central challenge that limits our understanding of Amazon’s global climate impact. ”
Ecosystem-wide analysis also delves into the most important details, because given how huge the Amazon Basin is, even seemingly small changes in the amount of greenhouse gases absorbed or released by the forest (and its microbial-rich soils) add to massive disturbances throughout the ecosystem.
Prolonged droughts decrease Amazon’s ability to absorb CO2 and increase the chances of wildfires, which in 2019 burned at a record rate. Like illegal fires that are lit to clear the earth, these forest fires turn trees into soot particles that absorb sunlight and cause the atmospheric temperature to increase in speed.
Meanwhile, industry-driven deforestation, 60% more since 2012 in the Brazilian Amazon, clears thousands and thousands of square miles of forest each year for mining and agriculture, causing soils, changing rainfall patterns and increasing the amount of reflected sunlight into the atmosphere where greenhouse gases await.
Add to this equation the construction of dams, extractive mining practices, seasonal floods, severe storms, soil compaction for farmland and grazing livestock, which are changing the forest and its emissions, and it is understandable. the way researchers were able to come to such a calamitous situation. conclusion.
The team recognizes a high degree of uncertainty in its results, which have resulted in a lack of data from some parts of the Amazon, especially its snake river systems, and the unique ecological characteristics of such a large forest. which creates its own climate. .
However, with the available data, the resounding result of their analysis is that the Amazon releases more gases that capture heat than it stores, creating a net warming effect in the Earth’s atmosphere.
Protecting the Amazon is now more urgent than ever and that includes halting deforestation and restoring indigenous land rights.
The research was published in Borders in forests and global change.