The Amazon rainforest could be gone within 49 years once reaching an ecological tipping point of no return and turn into a grassy savannah, scientists have warned.
The world’s largest ecosystems, like the Amazon, are likely to be gone much faster than previously thought once they start collapsing, a team of researchers found.
And the findings should serve as yet another wake-up call for policymakers to halt the cycle of destruction of the natural world, they said.
The speed of collapse is surprisingly disproportionate for large ecosystems; the study published Tuesday in the peer-reviewed journal Nature Communications stated.
“A forest that is 100 times bigger than another one does take longer to collapse, but it will take much less than 100 times the time … what this means is that the biggest ecosystems that we have in the world are likely to collapse much quicker than we think, in a matter of decades,” said John Dearing, professor of physical geography, who was part of the research team along with scientists from Bangor University in Wales and London’s School of Oriental and African Studies.
As humans, through rapid deforestation, overfishing and other activities are causing these ecosystems to collapse; once these habitats are gone, they will also be the ones to pay the price.
Dearing told CNN that the resources that ecosystems offer in terms of food or agriculture become severely diminished when they will collapse from their natural state.
The impact of such events over and over again had devastating effects on fishing communities, farmers, and others relying on natural resources. In 1992, when the Atlantic northwest cod fishery collapsed, a fishingmoratorium imposed by the Canadian government on Newfoundland and Labrador communities that had relied on fishing for 500 years.
Around 30,000 people lost their jobs. Though the government tried to help, providing financial aid, early retirement options, and retraining programs, the population of the province dropped by 10% in the following 10 years, and its rate of unemployment is still higher compared to the other parts of the country.
More recently, the United Nations has warned about the deadly clashes between farmers and herders that are becoming more common as fertile land turns into the desert in sub-Saharan Africa. During the last rainy season in Darfur, the African Union-United Nations Hybrid Operation in Darfur has warned about an increase in tensions over resources between the two communities that killed many people.
Predicting the tipping point
The scientists have not yet figured out how to predict the ensuing tipping point that once exceeded leads to a change in ecosystems, or certainly recognize that it has been reached. “Most tipping points have been viewed with hindsight, we have looked back and said ‘oh, it looks like the tipping point was x years ago,'” Dearing said.
According to some scientists, the Amazon forest, which is a crucial part of the global carbon cycle, is already at the tipping point right now.
For several years, Thomas Lovejoy, a professor at George Mason University in Virginia, and Carlos Nobre, a senior researcher at the Brazil’s University of São Paulo, have been warning in their research, separate from the Nature Communication study, that the rainforest is “teetering on the edge of functional destruction” as a result of aggressive deforestation on droughts.
The rainforest generates around 50% of its own rain by recycling moisture through trees and other vegetation. “The rainforest is central to the regional, and possibly even the global water cycle, it holds so much water, it has its own kind of micro climate, it affects the pressure systems and weather systems through the North Atlantic particularly,” Dearing said.
However, with the trees being cut down, the soil becomes dry, and the amount of water in the system declines. According to Lovejoy and Nobre, the point of no return at which the Amazon rainforeststarts drying out and turning into a savannah is “at hand.”
They said that the severe droughts of 2005, 2010, and 2015-16 “could well represent the first flickers of this ecological tipping point.”
Dearing said that when that happens, a huge amount of carbon will be released, which is now stored in the rainforest. The carbon the trees sequestered is put back into the atmosphere when they burn in wildfires or rot following deforestation.
“We will see a lot of species go extinct,” he said. “Some of those won’t be essential to our survival, but if it means that we lose genetic resources, we lose the possibility of new pharmaceuticals, then we’re losing a lot of that potential wealth that those forests give us.”
Climate change is making the destruction more likely
Environments cannot cope with the rate the world is getting warmer all-around “When you add in additional stresses like pollution, deforestation, overgrazing, overfishing, the fact that you’ve got this stress in the background just magnifies the chance that the systems could actually collapse quite quickly,” Dearing said.
The devastating impact of climate change on already vulnerable environments is visible through the rapid spread of bush fires in Australia last year.
Based on the shifts that happened in the past, Dearing’s team developed the model for predicting the speed of the ecosystem collapses. Across five continents, 42 ecosystems have been analyzed that have experienced dramatic changes. The lessons are gloomy. The Jamaican coral reefs were decimated in just 15 years converting into an algae-dominated ecosystem, while in only 20 years, the agricultural lands in Niger’s Maradi region turned into a desert.
In the past, during and after ice ages, there have been changes in ecosystems naturally when vegetation changed dramatically in the northern hemisphere. “During the ice ages, the bands of vegetation moved up and down as the environment becomes warmer or colder,” Dearing said.
However, these past changes took more than thousands and tens of thousands of years. “What we are talking about now is decades,” Dearing added.
However, in case of more abrupt natural shifts, for example, a sudden drought or a major volcanic eruption, the environments tend to bounce back, recovering into their former state relatively quickly.
Dearing said that the human-induced changes appear to be more permanent. “What we’re seeing is ecosystems that are not really bouncing back, they are staying in this kind of stable but degraded state.”
