Change and Instability in the Amazon Region

Supporting countless species, regulating the region’s weather patterns, and absorbing CO₂ from the atmosphere, the vast Amazon Rainforest sprawls across nine countries in South America. Unfortunately, for several decades now it has been subject to a combination of threats, with rampant deforestation driving habitat loss and climate change altering rainfall in the region. This 2024 study brought together 24 scientists from around the world with the aim of quantifying change in the Amazon, identifying the most vulnerable areas of rainforest, and investigating how any changes may trigger potential ‘tipping points’ across the ecosystem.

Background and purpose

The Amazon region is one of the most biodiverse in the world, home to over 14,000 plants [1], many of which are found nowhere else on Earth, as well as a myriad of animals and indigenous peoples. Its expansive rainforest is a vital carbon sink – it absorbs more carbon than it emits – but its size is rapidly diminishing due to deforestation, and some areas of the Amazon are now considered carbon sources, areas in which more carbon is released to the atmosphere than is absorbed [2]. Reforested areas have great potential to act as carbon sinks [3] but remain threatened by illegal deforestation, which disturbs the Amazon ecosystem and decreases its resilience; the ability to adapt to change. Such disturbance therefore heightens the rainforest’s vulnerability to changes in the climate, with a temperature increase of >2°C predicted to trigger the extensive death of the Amazonian vegetation [4]. It is critical that more is understood about the Amazon system in order to estimate what its tipping points are (points at which change in the region is so significant that it cannot be reversed), how these could be exceeded, and what the potential impacts of this may be across the region.

 Details 

The team of scientists used 40 years-worth of satellite and observational data, i.e. information collected by the researchers themselves, to model changes in climate and forest cover over time, helping to identify any transitions in the Amazon system. These models assessed how changes to the ecosystem’s natural state could impact forest resilience and water scarcity, and how this may relate to disturbance in the area. They then looked at the potential for the Amazon to change to an ‘alternative state’, in which forest patches may degrade into areas of savannah due to changes to the vegetation and local climate. Finally, the researchers assessed the robustness of their modelling approach and explored the implications of their study for policy across the Amazon region.

Findings 

The study found that changes to regional climate are already impacting the stability of the Amazon ecosystem, with the mean temperature of the dry season rising by 2°C over the past four decades and water scarcity increasing in parts of the rainforest. Furthermore, 10% of the forest was ‘‘highly likely’ to degrade and transition to savannah in the future, associated with disturbance from both human activities and climate change; smaller, fragmented patches were the most likely to transition. The scientists also explored the ability for new forest growth to absorb CO₂ and compensate for forest degradation elsewhere, but noted that more research was needed in this area. A key takeaway from this paper were the thresholds that the authors set in order to preserve the Amazon, including a 1.5°C limit on global temperature rise and no more than 10% accumulated deforestation, the rolling total of forest cover that is deforested over time. To achieve this, deforestation must be halted and 5% of the ecosystem restored. It should be highlighted that these predictions are uncertain and may represent overestimates or underestimates of reality. Nonetheless, the authors suggest several key actions to meet these propositions, including a reduction in greenhouse gas emissions, the expansion of existing protected areas, and the handing back of land to indigenous peoples who act as stewards for the forest. It is the scientists’ view that these actions will be critical in securing the future of the Amazon biome for centuries to come.

How to find Another Way

It is clear that policy changes are needed to protect the Amazon and encourage its restoration. Positive steps are being taken in Brazil, where deforestation has already fallen by two thirds under new president Lula [5]. However, we can also make a difference as consumers. One of the biggest drivers of Amazon deforestation is cattle farming and soy production for livestock feed. Livestock reared in the UK can also be fed soy that is contributing to land clearance in the Amazon. One way to directly reduce demand for this soy is to eat less meat! Start by trying out a meat-free recipe once per week and try to increase it gradually. We also have the power to push UK supermarkets to stop sourcing soy linked to deforestation. Whilst the Amazon may feel too far away for us to make a difference, this study shows that Earth’s systems are linked in complex ways; we therefore all have the chance to create a better future for people and the planet.

Article by Chloe Moriarty

References 

Study Paper: Flores BM, Montoya E, Sakschewski B, Nascimento N, Staal A, Betts RA…Hirota, M (2024) ‘Critical transitions in the Amazon forest system’, Nature, 626(7999):555-64. https://doi.org/10.1038/s41586-023-06970-0 

1. Cardoso D, Särkinen T, Alexander S, Amorim AM, Bittrich V, Celis M…Goldenberg R (2017) ‘Amazon plant diversity revealed by a taxonomically verified species list’, Proceedings of the National Academy of Sciences, 114(40):10695-700.

2. Gatti LV, Basso LS, Miller JB, Gloor M, Gatti Domingues L, Cassol HL…Neves, RAL (2021) ‘Amazonia as a carbon source linked to deforestation and climate change’, Nature, 595(7867):388-93. https://doi.org/10.1038/s41586-021-03629-6

3. Heinrich VH, Dalagnol R, Cassol HL, Rosan TM, de Almeida CT, Silva Junior CH…Aragão, LEOC (2021) ‘Large carbon sink potential of secondary forests in the Brazilian Amazon to mitigate climate change’, Nature Communications,12(1):1785. https://doi.org/10.1038/s41467-021-22050-1

4. Armstrong McKay DI, Staal A, Abrams JF, Winkelmann R, Sakschewski B, Loriani S…Lenton TM (2022) ‘Exceeding 1.5 C global warming could trigger multiple climate tipping points’, Science, 377(6611):eabn7950. https://doi.org/10.1126/science.abn7950
5. Mongabay (2023) ‘Amazon deforestation continues to fall under Lula’, Mongabay, 5 August. Available at https://news.mongabay.com/2023/08/amazon-deforestation-continues-to-fall-under-lula/ [Accessed 27/06/2024]