Almost half of the forests that make up the Amazon rainforest are on track to collapse in the next 16 years, an international team of scientists announced today.
Droughts, deforestation and fires threaten the rainforest, according to a new study, which found that between 10 and 47 percent of rainforests could be so deteriorated and degraded by 2050 that they would fall into a downward spiral of deterioration. the ecosystems.
The Amazon rainforest, sometimes described as “the lungs of the Earth” because its trees produce much of the world’s oxygen, depends on heavy rainfall. If humidity levels continue to fall as they do now, crucial forests could end up converting to grasslands.
Up to 38 percent of what’s left of the Amazon rainforest has been degraded by logging, under-canopy fires and repeated extreme droughts, while road networks are pushing damage to the entire core of the ecosystem, according to the study.
Wildfires, both those caused by people and those caused by drought, tend to spread closer to where roads are built.
All of these offenses against the Amazon, one of the Earth’s best defenses against global warming, have become less resilient.
This damage hasn’t necessarily pushed it past the point of no return, according to the study’s authors, a team of European and Brazilian scientists, but that point gets closer every year.
Long-standing natural relationships between environmental conditions and the Amazon rainforest ecosystem are being replaced by new ones, which is quickly making life difficult for native wildlife and people living in the Amazon basin, the researchers explained. authors of the study.
The Amazon rainforest, sometimes called “the lungs of the Earth,” is home to more than 10,000 species of plants and animals. They face extinction if too much of the Amazon is lost
The trees, plants, animals and humans that live in the forest have evolved over millions of years to cope with the hot, humid conditions of the local climate, as well as seasonal flooding and shallow, sandy, poor soil. in nutrients.
The rainforest thrives in these conditions.
But as wildfires and droughts become more common, trees cannot adapt quickly enough to cope with changing conditions.
The loss of forest in one area can generate “a self-propelling feedback loop” that leads to the loss of other areas of forest, according to the study published in the magazine Nature.
The impact of forest loss is not limited to the borders of the Amazon.
Deforestation for agriculture is one of the main causes of Amazon degradation and deforestation. Scientists say that by 2050, between 10 and 47 percent of the smaller forests that make up the Amazon could be irreparably damaged, in a spiral of downward destruction.
Moisture transported through the air by the so-called “flying rivers” of the Amazon – large amounts of airborne water vapor – is essential for precipitation in large areas of the South American continent.
Potsdam Institute for Climate Impact Research (PIK) scientist Boris Sakschewski, one of the authors of the study, said: “The southeastern Amazon has already gone from being a carbon sink to a source, which means that the Current human pressure is too high for the region to maintain its rainforest status in the long term.
‘But the problem does not end there. Since tropical forests enrich the air with a large amount of moisture that forms the basis of precipitation in the west and south of the continent, the loss of forest in one place can lead to the loss of forest in another in a feedback loop. self-propelled or simply a “tilt”. “
The current drought levels are the worst seen in the region in 50 years and have seen levels of the Río Negro, one of the region’s main rivers, at their lowest levels in 100 years.
The Amazon as a whole stores carbon equivalent to between 15 and 20 years of current human CO2 emissions. Forest loss will further drive global warming and intensify the consequences on forests, according to the report.
The study also analyzed examples of disturbed forests in various parts of the Amazon to understand what could happen to the ecosystem.
In some cases, forest collapse may not be obvious, the authors wrote.
For example, in some areas where trees have been cut down or burned, bamboo forests or so-called “liana forests” may thrive.
Both bamboo and liana forests may seem like thriving nature at first glance; After all, they have green plants.
But bamboo and vines can prevent large trees from taking root and reestablishing forest cover, so these areas can become trapped in a degraded state, dominated by opportunistic plants.
In other cases, the forest no longer recovers and remains trapped in a flammable, open-canopy state.
The expansion of open, flammable ecosystems throughout the core of the Amazon forest is particularly worrying because they can spread fires to adjacent forests.
The researchers called for limiting global warming to 1.5°C and limiting deforestation to 10 percent of the original tree cover of the Amazon forest, which requires ending large-scale deforestation and restoring at least 5 percent of the region, which has already seen up to 15 percent. of its lost forests.
Co-author Niklas Boers, from PIK and professor of Earth system modeling at the Technical University of Munich, said: “To keep the Amazon forest within safe limits, local and global efforts must be combined.
‘Deforestation and forest degradation must end and restoration must expand.
“Furthermore, much more needs to be done to stop greenhouse gas emissions around the world.”