When a system reaches a tipping point, everything changes quite suddenly and nothing is the same. Researchers are now wondering whether the Amazon rainforest is also in the process of tipping over and could irrevocably transform itself into a savannah landscape.
It is possible that large areas in the south-east of Amazonia in particular have already reached tipping points. At least that’s what counts report that the “Amazon Network of Georeferenced Socio-Environmental Information” (RAISG) published some time ago in cooperation with the Coordinator of the Indigenous Organizations of the Amazon Basin (COICA), which represents the more than 500 indigenous communities in South America. Accordingly, 34 percent of the Brazilian and 24 percent of the Bolivian rainforest are in a process of transformation. Things are looking a little better in Ecuador, Colombia and Peru, while northern rainforest states such as Venezuela have so far been little affected.
“Basically, this is not a new finding,” says Florian Wittmann, professor at the Institute for Geology and Geoecology at the Karlsruhe Institute of Technology. “For several years, studies have repeatedly claimed that the tipping points in the Amazon had been exceeded.” It is difficult to say whether the Amazon system as a whole is already tipping over, says Wittmann, who researches the ecology of the wetlands in the Amazon with a view to the consequences of global warming: “We cannot scientifically describe an event that we are witnessing in this kind have never experienced. We don’t know how exactly such a tipping point manifests itself.”
Savannahification is already taking place in the south and south-east
He suspects that the region in the south and south-east of Amazonia has actually already tilted, says Wittmann, as the RAISG study also claims. Landscape that has been deforested in this region and is now savanna no longer regenerates. The area is now subject to natural savannahification due to increased erosion in the short term and less precipitation in the long term.
When a tipping point is passed, a sudden, radical change in a system such as the Amazon rainforest occurs. In a figurative sense, this happens overnight, although the environmental parameters have gradually changed over a long period of time, says Niklas Boers, who researches modeling of the Earth system and specifically tipping points at the Technical University of Munich and the Potsdam Institute for Climate Impact Research.
“You can think of the moist air masses flowing inland from the Atlantic towards the Andes as a large atmospheric river. In this picture, the Amazon then acts as a huge lake that holds the water masses and channels them on to the Andes from where be diverted to the south,” said Boers. In this way, a large part of the continent is supplied with water: “Amazonia is important for the South American monsoon system. About 60 to 70 percent of the moisture south of Amazonia depends on this atmospheric lake, which the rainforest forms.”
Without the rainforest, there would be no intake system, which draws most of the humid air in from the Atlantic, says Boers. The forest maintains the circulation of moisture. “Rain over the forest releases latent heat. The warm air rises, which lowers the air pressure and creates a pressure gradient between the rainforest and the Atlantic. The flow of humid air from the Atlantic to South America is increased. This in turn causes more rain, “a classic positive feedback,” says Boers. The effect is self-perpetuating deforestation If it gets too small, then this mechanism fails, explains Boers. At some point, not enough water is held in the now interrupted cycle. Instead, it drains directly into the sea via rivers. The system collapses, the area dries up and savannah is formed from rainforest.
A problem alongside deforestation in the region is the climate crisis. According to model projections, global warming will make South America drier. Niklas Boers says: “The system is currently fighting on two fronts.” In fact, 2005, 2010 and 2015 saw devastating droughts. Parts of the vegetation cannot cope with this. What used to happen once in a hundred years now happened three times in a decade. “It can be a statistical anomaly. But it can also be due to the consequences of global warming.” In response, the Amazon rainforest has transformed from a global CO₂ store into a source of CO₂ emissions in recent years.
In addition to mining, dams and oil plantations, agriculture is a particular problem
Florian Wittmann emphasizes the great importance of the Amazon forest for North and South America: “The Amazon is the air conditioner of the western world,” says Wittmann. After the oceans, forests are also the largest reservoirs of climate-damaging gases. The ecosystem also provides genetic resources. In other words, animal, plant or fungal material that is used for nutrition or the manufacture of medicines. Wittmann says: “Our natural laboratory for food and medicine is endangered – and with it our existence.”
The problem after crossing a tipping point is that the process is irreversible. When the forest disappears, there is no moisture to replant the original tree species. In addition, according to Wittmann, only around 30 percent of tree species in the Amazon have been scientifically described: “We can only manually reforest those species that we know. It may take centuries or even millennia for the rest to return.” So far, only five percent of the native tree species have been successfully reforested.
Nevertheless, the initiators of the deforestation study advocate reforestation: a total of 26 percent of the Amazon region is now either deforested or badly affected. Immediate action is needed to keep the ecosystem stable and avoid a tipping over of the entire Amazon. That is why they are launching the “Amazonia for Life” initiative, which calls for a total of 80 percent of the former forest to be protected by 2025 – in particular the 33 percent of the area that are still considered intact and the 41 percent that are little damaged are. Six percent would also have to be reforested in order to achieve the goal.
According to the study, in addition to mining, dams and oil plantations, agriculture is the main reason for the massive deforestation at 84 percent, especially in Brazil and Bolivia. The two countries are jointly responsible for 90 percent of the destroyed area in the Amazon.
The authors also see a reason for the deforestation in the fact that South America is one of the most indebted regions in the world. The solution is said to be a conditional haircut: the nine states that share the Amazon basin are to be forgiven part of their national debt if they commit to the goal of conserving 80 percent of the rainforest by 2025. Florian Wittmann thinks the necessary reforestation is possible, but it is a huge challenge: “Six percent of 6.8 million square kilometers is an enormous amount.”
Indigenous territories are often cheaper and just as effective as protected areas
In order to preserve the Amazon, the study also urges recognizing indigenous territories. At 48 percent, almost half of Amazonia is either state protected areas or indigenous territories. The proportion of both areas is roughly evenly distributed, says Dirk Embert, WWF’s South America officer. “Although indigenous territories usually don’t receive government funding like protected areas, they offer just as good protection.” Protected areas are comparatively very expensive, according to Embert. “If, on the other hand, the state lacks the means, then the protective measures are toothless.” Indigenous territories, on the other hand, cost little on the one hand, since the people living there inhabited and defended their ancestral homeland, and on the other hand they protected the habitat. The study also states that where the state is weak, activities such as illegal mining take place.
Embert emphasizes that one should not romanticize the indigenous communities: “These people also want to send their children to school and a cell tower in the village for cell phone reception.” If you don’t enable them to manage their traditional way of life in such a way that they can lead a dignified life, then these people also do mining.
After all: Brazil’s newly elected President Lula has promised to take action against illegal mining and land grabs and to end deforestation. The protection of the remaining rainforests is also an issue at the climate conference in Sharm el-Sheikh. Because one thing is clear: without climate protection, the rainforests have no chance in the long term – and vice versa.
