“We must act immediately,” urges the author of a study indicating that the critical forest has surpassed a safe threshold and requires restoration
A study has revealed that as a consequence of water stress, land clearance, and climate disruption, up to half of the Amazon rainforest could reach a tipping point by 2050. This paper, the most comprehensive analysis to date of the cumulative impacts of local human activities and the global climate crisis, cautioned that the forest had already exceeded a safe threshold. It emphasized the need for action to restore degraded areas and enhance the ecosystem’s resilience.
Lead author Bernardo Flores of the Federal University of Santa Catarina, Brazil, expressed surprise at the findings, which indicated a potential transition from gradual to rapid forest decline earlier than anticipated.
He noted that the forest was already exhibiting signs of increased weakness and uniformity. “By 2050, this process will accelerate rapidly. We must take action immediately. Once we surpass the tipping point, we will no longer be able to control how the system behaves.”
Addressing this issue requires global intervention because even if deforestation were halted locally, collapse would be unavoidable without a worldwide reduction in the CO2 emissions responsible for climate disruption.
For 65 million years, the Amazonian forests have endured climatic fluctuations. However, the region is now facing unprecedented stress from drought, heat, fire, and deforestation, which are penetrating even the deep central areas of the biome. This is altering the forest’s functionality, resulting in reduced rainfall in many areas and transforming a carbon sink into a carbon emitter.
Concerns regarding a potential tipping point in the Amazon have been a topic of discussion for the past two decades. Previous models suggested that this tipping point could occur when 20% to 25% of the forest is cleared. However, the new study, published in Nature on Wednesday, delved deeper into the issue, examining evidence for five drivers of water stress and identifying critical thresholds. These thresholds, if surpassed, could lead to local, regional, or even biome-wide collapse of the forest.
The study estimated that by 2050, between 10% and 47% of Amazonian forests would be exposed to compounding disturbances that could trigger unforeseen ecosystem-wide transitions. Such transitions could have detrimental effects on regional climate change.
The study determined that to prevent this scenario, a safe boundary with a buffer zone is necessary. This boundary would limit deforestation to 10% of the Amazon region and keep global warming within 1.5 degrees Celsius above pre-industrial levels.
However, it has already been surpassed. The study revealed that 15% of the Amazon has already been deforested, and an additional 17% has been degraded due to human activities such as logging, fires, and under-canopy extraction. Furthermore, 38% of the Amazon may be weakened as a result of prolonged droughts over the past decade.
By combining recent ground data, proxy indicators of historical trends, and computer modeling incorporating regional and global climate trends, the study outlined three potential ecosystem trajectories: a white-sand savanna, a degraded open canopy, and a degraded forest. All of these trajectories would lead to increased fire and drought in the region.
In central and southern parts of the Amazon, dry season temperatures have risen by 2 degrees Celsius compared to 40 years ago. Models predict that by 2050, there will be between 10 and 30 additional dry days compared to current levels, along with an annual maximum temperature increase of between 2 and 4 degrees Celsius. According to the paper, this temperature rise would subject “the forest and local peoples to potentially unbearable heat” and could potentially decrease forest productivity and carbon storage capacity.
Rainfall patterns are changing. Since the early 1980s, parts of the central and peripheral Amazon forest have experienced increased dryness, with annual rainfall in the southern Bolivian Amazon decreasing by up to 20mm. In contrast, the western and eastern regions of the Amazon are becoming wetter. The paper suggests that if these trends persist, they will reshape ecosystem resilience, leading some regions to become savanna, while much of the rest of the Amazon is likely to remain in a degraded state.
These changes will significantly impact local and regional populations. The Amazon harbors more than 10% of the Earth’s terrestrial biodiversity, stores 15-20 years’ worth of global CO2 emissions, contributes up to 50% of the region’s rainfall, and is vital for moisture supply across South America. Its evapotranspiration helps cool and stabilize the world’s climate. However, its full importance and complexity are not yet fully understood.
The study highlighted several shortcomings in current computer climate models. These models do not adequately account for the compounding effects of different disturbances such as fire, drought, and land clearance, nor do they consider the varying impacts on different types of forests. They also fail to incorporate plans for new infrastructure, such as the proposed BR319 road, which could facilitate illegal mining and land grabbing over a vast area. Additionally, these models do not account for how forest degradation affects rain recycling or whether the increased CO2 in the atmosphere is enhancing or weakening forest resilience.
The simplicity of current models can lead to unexpected outcomes, as demonstrated by last year’s severe drought. Flores emphasized that recent events, like the El Niño phenomenon, indicate that changes are occurring more rapidly than anticipated. Therefore, precautionary measures are essential. Achieving net zero emissions and net zero deforestation as soon as possible is imperative. Action must be taken immediately, as the loss of the Amazon would pose significant challenges for humanity.
