by Dr. Fabiana S. Paula
Research Scientist at University of Sao Paulo
In the last few years, the concept of climate change have left the corridors of the universities and research institutes to reach the most remote places. This is for sure a big achievement for science, as it is impossible to fight climate change without fighting climate change denial first. I confess, until recently, I used to think about climate change only as a subject of research. Something to be studied to create mitigation strategies for a distant reality. But last week, while I was reading the news, I was overwhelmed and feeling hopeless. I could not stop thinking about all those climate change reports that I had seen and, in one way or another, were always pointing out the importance of the Amazon in the final balance.
The recent increase in tropical forest fires have risen the concerns about deforestation rates in the Amazon. In Brazil, after many years of steady decline in deforestation rates, we are seeing a sudden alarming rise. Brazilian and international researchers claim that the rise in deforestation is the result of “pro-development” policies of the Brazilian President Jair Bolsonaro and his government (Science, 2019). Brazil has endured a series of actions against the protection of its ecosystems. IBAMA, the environmental Brazilian agency, has been the target of violent budget cuts. The director of the institute responsible for reporting deforestation activities (INPE) was also branded as a liar and fired after reporting the results of scientific research. Besides, the scientific structure in Brazil that was a model for Latin America and the world in the past governments, has been affected after Bolsonaro election. Scientists working with biodiversity and environment protection will have major budget cuts from next September (Nature, 2019).
Why care about the fires in the Amazon?
Alterations in the amazon will cause irreversible changes on climate at local and global scale. Forests in the Amazon contain billions of tonnes of carbon . So the fires not only wipe out biodiversity, but also release large amounts of carbon to the atmosphere, that means an acceleration on global warming effects.
Large portions of these areas impacted by fires are used to install pastures for beef production. Cattle ranching is also a source of another powerful greenhouse gas: methane. This gas is 25 times more dangerous (in terms of global warming) than the carbon dioxide regarding their heat retention power. Beef production is a methane source, as cows are “living reactors” and they have in their guts microbes called methanogens (methane producers). Considering the large areas occupied by cattle in the Amazon (and now in expansion), the contributions of this practice may be very important for the global carbon balance.
Maintaining the Carbon Balance
Soils also store enormous amounts of Carbon, and the activity of soil microbes is directly linked to long term storage and release of Carbon to the atmosphere. The same kind of microbes, methanogens, that live in cow guts are present in soils. However, the dynamics of the methane release in this environment are also dependent on the action of another kind of microbes: Methanotrophs. These microbes consume methane produced by methanogens in the soil, and can also sequester the gas from the atmosphere. Those relationships in the Amazonian forest soils results in a negative methane flux, which may be an additional mechanism of climate change buffering provided by the Amazon forest.
Now, I’m going to tell you something that may make you even more worried about deforestation in the Amazon. When lands in the amazon are impacted by deforestation and replaced by pastures for cattle, the methane flux in the soil reverses. Pasture soils tend to lose their methane sink capability, and even become a source of the gas. The causes of this are still being investigated, but it has been shown that the quantities of methanogens and methanotrophs in the soil change drastically (Meyer et al., 2017). So, we are not only releasing carbon from the trees. We are also unlocking carbon stored in the soil and playing with the balance of methane.
Beef production is well known to be among the major contributors to climate change. But in the Amazon it is even more worrying, as a highly predatory system is leading to the high deforestation rates. Large scale cattle ranchers do not invest minimal resources to ensure long term productivity of their lands, and consequently productivity decreases with time. When that happens, rather than managing the land, it is less costly to simply abandon it and put down another forest. The abandoned lands take very long time to regenerate and restore functions similar to the original forest.
To make a positive impact we should support scientific research that works on finding sustainable ways to manage land and recover areas abandoned by cattle ranchers. Get involved or donate to organisations that protect tropical forest. Promote a conscious consumption, where you analyse the origin of your food and the real environmental cost (WWF) . Raise awareness in your country and talk to policy makers about the need of international regulations for food imports based on sustainable practices. Share certified information about the climate crisis on social media and discuss climate change denial with your close ones. This could be the opportunity to work together and fight climate change.
Edited by Mind the Microbes.
More sources of information about the Amazon in Peru, Colombia, Bolivia and Ecuador : https://maaproject.org/en/