PARIS, France — The
Brazilian Amazon released nearly
20 percent more carbon dioxide into the atmosphere over the last decade than it
absorbed, according to a stunning report that shows humanity can no longer
depend on the world’s largest tropical forest to help absorb manmade carbon
pollution.
اضافة اعلان
From 2010 through 2019, Brazil’s Amazon basin gave off 16.6
billion tons of CO2, while drawing down only 13.9 billion tons, researchers
reported Thursday in the journal
Nature Climate Change.
The study looked at the volume of CO2 absorbed and stored as
the forest grows, versus the amounts released back into the atmosphere as it
has been burned down or destroyed.
“We half-expected it, but it is the first time that we have
figures showing that the Brazilian Amazon has flipped, and is now a net
emitter,” said co-author Jean-Pierre Wigneron, a scientist at France’s National
Institute for Agronomic Research (INRA).
“We don’t know at what point the changeover could become
irreversible,” he told AFP in an interview.
The study also showed that deforestation -- through fires
and clear-cutting -- increased nearly four-fold in 2019 compared to either of
the two previous years, from about one million hectares (2.5 million acres) to
3.9 million hectares, an area the size of the Netherlands.
“Brazil saw a sharp decline in the application of
environmental protection policies after the change of government in 2019,” the
INRA said in a statement.
Brazilian President
Jair Bolsonaro was sworn into office on
January 1, 2019.
Terrestrial ecosystems worldwide have been a crucial ally as
the world struggles to curb CO2 emissions, which topped 40 billion tons in
2019.
Over the last half century, plants and soil have
consistently absorbed about 30 percent of those emissions, even as those
emissions increased by 50 percent over than period.
Oceans have also helped, soaking up more than 20 percent.
Tipping points
The Amazon basin contains about half of the world’s tropical
rainforests, which are more effective at soaking up and storing carbon that
other types of vegetation.
If the region were to become a net source rather than a
“sink” of CO2, tackling the climate crisis will be that much harder.
Using new methods of analyzing satellite data developed at
the University of Oklahoma, the international team of researchers also showed
for the first time that degraded forests were a more significant source of
planet-warming CO2 emissions that outright deforestation.
Over the same 10-year period, degradation — caused by
fragmentation, selective cutting, or fires that damage but do not destroy trees
— caused three times more emissions that outright destruction of forests.
The data examined in the study only covers Brazil, which
holds some 60 percent of the Amazonian rainforest.
Taking the rest of region into account, “the Amazon basin as
a whole is probably (carbon) neutral,” said Wigneron.
“But in the other countries with Amazon rainforest,
deforestation is on the rise too, and drought has become more intense.”
Climate change looms as a major threat, and could — above a
certain threshold of global warming — see the continent’s rainforest tip into a
much drier savannah state, recent studies have shown.
This would have devastating consequences not only to the
region, which currently harbors a significant percentage of the world’s
biodiversity, but globally as well.
The Amazon rainforest is one of a dozen so-called “tipping
points” in the climate system.
Ice sheets atop Greenland and the West Antarctic, Siberian
permafrost loaded with CO2 and methane, monsoon rains in South Asia, coral reef
ecosystems, the jet stream — all are vulnerable to point-of-no-return
transitions that would radically alter the world as we know it.
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