Collapse of the Amazon: the important and little commented points of the new study – 02/22/2024 – Fundamental Science

Last week, a headline appeared on the main pages of media outlets in Brazil and around the world: by 2050, almost half of the Amazon could collapse and reach the so-called point of no return, when the forest loses its ability to fully recover. .

TVs, newspapers and news portals reproduced the alarming findings of a study that was on the cover of Nature magazine, led by researchers Marina Hirota and Bernardo Flores, from UFSC (Federal University of Santa Catarina), with collaborators from Brazil, Europe and the United States. They estimate that, if no measures are taken, 10% to 47% of the forest will have been exposed to threats so serious that, in 25 years, it will lose its ability to maintain itself and will undergo changes in its ecosystem – the forest may remain in a configuration degraded, for example.

These changes can impact the climate, reducing rainfall in the region, preventing the forest from capturing carbon dioxide from the atmosphere and increasing the risk of large-scale collapse. In the article, the researchers determine the critical limits for the main stress factors in the Amazon – such as rising temperatures, greater intensity of extreme droughts, deforestation and fires – which, if exceeded, could lead to this collapse.

The scenario is serious, and sounding the alarm is essential to show the urgency of taking action as soon as possible. Therefore, the press tends to draw attention to the worst possible scenario: the collapse of almost half of the forest in 25 years. But the study brings other relevant aspects that were left aside in the journalistic coverage.

Marina Hirota, who says she is optimistic about our ability to react to the problem, listed three important points from the study published in Nature and which ended up being little explored by the press:

1- We still have time (but not much)

When it is said that from 2050 onwards we will reach the point of no return, this does not mean that the Amazon rainforest will necessarily collapse the next day. We are talking about a time scale very different from that of human life: after all, the Earth is about 4.6 billion years old. On this scale, “fast” could mean 300 years.

“Once this point is crossed, the changes we could make now will not necessarily be as efficient later on,” explains Hirota. “If we try to stop deforestation after crossing the point of no return, the effect of our actions will be much smaller.” In other words: we have time, but if we want to avoid collapse in a more efficient way, this must be done as soon as possible.

2- The Amazon is not just one thing

The researchers observed that the effects are happening quite heterogeneously across regions. This is because the Amazon itself is not homogeneous, but an immense biome, shaped over tens of thousands of years, and with several different ecosystems within it – for example, savannas in the middle of the forest that are completely natural, flooded regions, more or less fertile, which respond in different ways to disturbances. “We cannot think that trees are all the same”, warns Hirota.

That’s why the study talks about local and systemic points of no return: different stress factors, such as extreme droughts, fires and deforestation, generate different responses, destabilize the various parts of the Amazon in an erratic way, and this heterogeneity saves us some time. It is as if, in the human body, each organ begins to fail at different times – first the liver, then the stomach, then the kidney. For some time, the body is still able to function, even though everything is interconnected. But, at some point, he suffers a systemic collapse and reaches a state of death.

3- The solution exists

“It is important to make it clear that we are capable of making the necessary changes through combined actions and uniting various levels of governance”, says Marina Hirota. “For example, local efforts to drastically reduce deforestation, combined with forest restoration initiatives coordinated between the Federation, states and municipalities.”

Local action must also be connected to global efforts to curb the emission of greenhouse gases, thus mitigating the impacts of climate change. It is also essential to integrate knowledge – not only that produced by scientists, but also that of the people of the forests, of the people who live in the place. And, finally, connect this knowledge to public policies, which must be designed based on solid evidence.

To build this bridge, in fact, Marina Hirota participates, together with other researchers, in a pilot project of a research and public policy center dedicated to tropical ecology. At this moment, the scientists involved in the pilot are working to define its priority axes and to synthesize existing knowledge. While one group focuses on long-term research, such as mapping biodiversity, another thinks about research with more immediate results that can inform public managers. There is still no forecast, however, for the center to be opened.

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Clarice Cudischevitch is a science journalist and Communications manager at Instituto Serrapilheira.

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