Agence France-PresseJuly 16, 2021 12:41:27 IST
Climate change and deforestation have translated much of the Amazon basin from absorption to global warming into carbon dioxide emissions. This change could turn humanity’s greatest natural ally in the fight against global warming into an enemy, scientists reported on Wednesday.
Hundreds of high-air samples collected over the past decade showed that the southeastern Amazon in particular has shifted from a “sink” to a source of carbon dioxide, the main greenhouse gas, they told the newspaper Nature.
Terrestrial ecosystems will be crucial globally as the world strives to curb CO2 emissions in excess of 40 billion tonnes in 2019.
Over the last half century, plants and soil have consistently absorbed more than a quarter of these emissions, even if CO2 emissions increase by 50 percent.
The Amazon Basin has about half of the world’s tropical rainforests that absorb and store carbon more efficiently than other vegetation.
If the Amazon – 450 billion tonnes of CO2 locked in its trees and soil – became a single source and not a carbon sink, the fight against the climate crisis would be much more challenging.
According to the study, the eastern part of the eastern Amazon has been altered by several factors.
“Deforestation and forest degradation are undermining the Amazon’s ability to act as a carbon sink,” the authors noted.
Since 1970, the area’s tropical forests have shrunk by 17 percent, mostly to pastures for cattle and the crops that feed them.
Forests are usually cleaned with fire, which both releases huge amounts of carbon dioxide and reduces the number of trees available to absorb it.
Climate change itself is also a key factor.
Dry season temperatures have risen by nearly three degrees Celsius from pre-industrial levels, tripling the global average.
Together, these drivers “question the ability of tropical forests to sequester large amounts of carbon dioxide from fossil fuels in the future,” Scott Denning, a atmospheric spokesman at Colorado State University, said in a comment. Nature.
The extent to which the Amazon basin lost its ability to absorb carbon dioxide has long been a burning issue, but satellite data – in part because of the constant cloud cover – has not been able to provide a complete answer.
To circumvent this problem, scientists led by Luciana Gatti of the National Space Research Institute in Sao Jose dos Campos, Brazil, collected nearly 600 carbon dioxide and carbon monoxide samples from planes in 2010-2018 at altitudes up to 4.5 kilometers (miles) above the forest floor.
According to the Northwest Amazon, they were in carbon balance, absorbing as much carbon dioxide into the atmosphere as it gave.
But the eastern Amazon region – especially during the dry season – releases much more than it absorbed.
A recent study using a different method found that the Brazilian Amazon released nearly 20 percent more carbon dioxide over the past decade than it absorbed in 2010-2019.
Above a certain global warming threshold, global warming may see the continent’s rainforest tip as a much drier savannah state, recent research has shown.
This would have devastating consequences both for a region that currently has a significant percentage of global biodiversity and globally.
The Amazon rainforest is one of the ten so-called air-conditioning systems. “From the turning point”.
Ice cover Siberian permafrost loaded with Greenland and Western Antarctica, CO2 and methane, monsoon rains in South Asia, coral reef ecosystems, jet stream – are all vulnerable to return point shifts that radically change the world as we know it.