“If the forest disappears, it changes the climate and rainfall of the whole continent”

27 August 2019, by Christina Krätzig

Photo: NASA/FIRMS

Fires burning on the South American continent 27 August 2019

Every summer, farmers in the Amazonian basin light fires, to clear land for farming. Currently, there are thousands of forest fires that are burning out of control. Brazilian researcher Debora Ferriera Pestana, a doctoral graduate of Universität Hamburg, explains why the forest is so important as a carbon sink and source of rainfall, and how its destruction could result in widespread desertification.

Ms. Pestana, how important is the Amazonian rainforest for the earth’s climate system?

The Amazonian rainforest is the largest forest in the world, and immensely important for the climate. This is for two reasons: Firstly, its biomass stores the carbon dioxide, a greenhouse gas, in its biomass, which can be released into the atmosphere by fire, or decomposition. That whole enormous forest is estimated to contain 86 billion tonnes of carbon dioxide, which is a quarter of all carbon dioxide on earth. The wildfires this summer will release 220 million tonnes of carbon dioxide. A comparison: The whole EU emits “only” four million tonnes of carbon dioxide. If the whole forest were to be destroyed, it would change the climate of the whole world. We would probably then no longer be able to stop climate change.

A second element is the humidity that rainforests produce. The trees absorb ground water from under the earth and release it through their leaves. The rain that results doesn’t just fall over the forest itself, but also over other regions in South and North America. If the forest were to disappear, partially or completely, it would change the rainfall patterns across the whole continent. Researchers have calculated that the area south of the Amazonian basin may change to include more steppes or even deserts.

What about the oxygen the forest produces?

This oxygen is reabsorbed by the forest. In contrast to what most people think, it is the oceans and not the forests that are the lungs of the planet. They product about half of the oxygen the world needs,

Could the burnt forest areas regenerate?

They still can, but soon this will no longer be the case. In Brazil, between 16 and 20 percent of the rainforest has already been destroyed. Experts estimated the “point of no return” is somewhere between 25 and 40 percent. After that, the hydrological cycle of the forest will collapse. Also, the fertile soil gets washed or blown away, and young forests can’t grow in barren soil.

We also have to consider the loss of biodiversity. There is an unimaginable species diversity in the Amazon, with many species only existing in small areas. If these areas are destroyed, the “endemic species” will also disappear, a not a single person will notice. 

Why is the forest burning?

The forest is burning because people set fire to it. It needs to be said straight-up there are not natural fires in a rainforest. Farmers cut down the trees, let the cleared area dry and when it is, set fire to it to open space for farming cattle and planting soy beans. Sometimes they announce these activities publicly, like the “Day of Fire” on 10 August, when dozens of fires were set.

And is that legal?

That is not legal. A large part of the rainforest is protected by law. There are laws that apply all over Brazil that nature should be protected. For example, farmers have to leave a certain percentage of their land in its original state, in the rainforest, 50 percent. The problem is, these laws are not enforced. The agricultural lobby is powerful, and there is a lot of corruption. During the election, President Jair Bolsonaro openly said that he wants to “develop” the rainforest and dispossess the indigenous population. The farmers have understood that they do not have to worry about repurcussions if they break the law.

What can people in Brazil, or in Europe, do to protect the forest?

In Brazil, people are slowly starting to change their thinking. The smoke from the forest fires can be seen as far away as the big cities in the south, 3000 km from the Amazon. This has shocked people, along with the international outcry against the destruction of nature. Brazilian agriculture depends on its export markets. If Europeans stop buying Brazilian beef or soy products from the rainforest areas, the farmers would have to change their behavior.

Does this change of heart also extend to the president?

Sadly, no,