Half of the Amazon is heading towards the point of no return by 2050 – 02/14/2024 – Environment

A group of Brazilian scientists estimates that, by the year 2050, 10% to 47% of the Amazon forest will be exposed to serious threats and may undergo an ecosystem transition, with loss of forest resilience and conversion to other forms of the biome, unable to fulfill the role of carbon sink played by the Amazon.

It is the so-called point of no return, when the forest no longer finds forms of feedback and collapses, totally or partially, converting into other forms of biological existence.

This inflection point for the Amazon is one of the main focuses of attention in the scientific discussion on climate change, due to the impacts on the climate, which go beyond the limits of the biome, to the emission of CO_two and for the way of life inside and outside the Amazon region.

Estimates taken into account in other studies indicate the possibility of no return with deforestation of 20% to 25% of the forest. Vegetation loss is currently in a range of 14% to 20%, depending on the criteria used and the area analyzed.

The Lula (PT) government promised to eliminate deforestation in the Amazon by 2030, a goal that forms part of Brazil’s commitment to the Paris Agreement. The agreement, defined in 2015 within the scope of the UN (United Nations), seeks to limit global warming, with the prospect that the increase in temperature will not exceed 1.5°C in relation to pre-industrial levels.

In the last five years, the Amazon lost 54,600 km^two in Brazilian territory, according to official data from Inpe (National Institute for Space Research). The rate of increase in devastation was interrupted in the first year of Lula’s government.

The new study conducted by Brazilian researchers states that the Amazon is increasingly exposed to pressure, with rising temperatures, extreme droughts, deforestation and fire, even in the most central or remote areas. The collapse of the biome could be local, regional or even total, which would worsen climate change, says the study.

It is necessary to stop deforestation and degradation and expand reforestation initiatives, say the researchers.

The scientific article was published this Wednesday (14) in the journal Nature. The study is led by researchers Marina Hirota and Bernardo Flores, from UFSC (Federal University of Santa Catarina), and has the participation of scientists from Brazil (such as Carlos Nobre, José Marengo and Erika Berenguer), the United States and Europe. The research was funded by the Serrapilheira Institute.

Higher temperatures, extreme droughts, deforestation and fire weaken mechanisms that guarantee the forest’s resilience, with a direct influence on the rainfall cycle. This brings the biome closer to the “critical transition”, the point of no return.

Among the critical limits cited by the researchers are an increase in temperature above 1.5°C and accumulated deforestation of 20% of forest cover.

“We are approaching all thresholds. At the rate we are going, they will all be reached in this century. And the interaction between all of them can make it happen sooner than expected”, says Bernardo Flores.

“If we want to avoid a systemic transition, we need to adopt a preventative approach that keeps forests resilient in the coming decades,” says Marina Hirota.

In 2023, the Brazilian Amazon experienced a historic drought, with record low rivers, fires and a radical change in the way of life of people living in the region, especially in traditional communities.

The extreme drought lasted longer than previous droughts, rain was much scarcer (in drought and flood) and rivers dried up drastically, leaving entire communities without drinking water, without food and without means of transportation. Municipalities like Manaus, the most populous city in the Amazon, with 2 million people, were inundated by waves of smoke for months on end.

The climate extreme in the Amazon was a combination of the effects of El Niño, warming of the North Tropical Atlantic, climate change and forest degradation. What happened in 2023 will impact 2024.

The biome is located in nine countries, a region with 40 million people, of which 2.2 million are indigenous people from 300 ethnicities, the study points out. Forest loss directly impacts life in these communities, researchers say.

The models used for the research project, by 2050, a significant increase in dry days (from 10 to 30 days) and temperature (from 2°C to 4°C). Thus, there may be a steam deficit and a water crisis resulting from this.

There are signs of fragility in forests considered to be standing. Long-term field monitoring indicates an increase in tree mortality in different locations, a consequence of forest degradation.

This reduces carbon storage and leads to replacement by species more prone to drought, the scientific article cites. Portions of the Amazon already emit more carbon than they absorb.

Ten percent of the Amazon forest has a high potential for transition, including to a feature with low tree cover, a savannization of the biome. Another alternative forest composition may occur in the more central Amazon, along highways such as BR-319 and Transamazônica, the research points out.

The greatest transition potential would be associated with deforestation frontiers, which occur in places with large highway projects. More remote and larger areas, associated with conservation units and indigenous lands, have low transition potential, according to the researchers.