The importance of the Amazon rainforest for the planet and its inhabitants cannot be overestimated, scientists from various disciplines agree. Biologists emphasize the gigantic biodiversity of the area, which with an area of around six million square kilometers is larger than the European Union. It is estimated that 2.5 million species of insects, thousands of birds and fish, and hundreds of mammals, amphibians and reptiles live there. The forest dwellers include the pygmy marmoset, which is just 15 centimeters long, and the two-meter-long arapaima, one of the largest freshwater fish on earth. Anacondas are found here, various species of poison dart frog and the scarlet macaw, one of the largest parrots in the world. Botanists also assume that more than a thousand different trees and several thousand other higher plants grow on one square kilometer. Nowhere else in the world are there so many different species.
From the arapaima to the pygmy marmoset: nowhere else do so many different species live
Climate researchers emphasize that the earth would have warmed up much more quickly without the rainforest. The area acts as a huge carbon sink: the many plants fish the greenhouse gas carbon dioxide (CO₂) out of the air during photosynthesis and convert it into various carbon compounds, which they incorporate into leaves, branches and twigs as they grow. This renders a large part of the CO₂ produced by humans harmless because it is firmly bound in the plants. An estimated 45 billion tons of carbon are bound in this way in the plants of the Amazon rainforest.
All of this is threatened by the destruction of the rainforest. The deforestation even damages the climate twice over. First, all the CO₂ bound in the plants is released in one fell swoop; and after that there are fewer plants that could take the greenhouse gas out of the atmosphere.
The second major threat to the forest is climate change: the average temperature is already up to 1.5 degrees above pre-industrial levels. In the past, severe droughts in the Amazon rainforest only happened once every hundred years. Between the years 2005 and 2015 there were suddenly three. The faster the droughts follow one another, i.e. the less time the forest dwellers have to recover from them – the greater the likelihood that the forest will no longer be able to regenerate and will die.
In response to these pressures, the Amazon rainforest is progressively evolving from a carbon sink to a carbon source. This means that the bottom line is that more carbon dioxide is released through clearing and the death of plants than the intact plants can bind. Some experts even fear that the rainforest is close to a so-called tipping point or that parts – especially in the southeastern Amazon – may already have passed this point. Then the forest would no longer be able to sustain itself, but would gradually turn into a savannah. At the moment about 20 percent of the original rainforest has been destroyed. Was that too much, or can the system withstand 40 percent? One does not know. What is known is that a collapse would have dramatic effects on the global climate.