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Savannisation of Amazon Forest
Context:
The Amazon region is experiencing its second consecutive year of severe drought, impacting biodiversity and communities dependent on waterways. This trend reimposes the debate of increasing Savannisation of amazon forest.
Key Statistics:
- River Levels: The Madeira River in Porto Velho, Brazil, dropped to 48 cm, far below the normal 332 cm.
- In 2023, most of the major rivers in the Amazon, including the Solimoes, Purus, Acre and Branco rivers, experienced extreme drops in water levels or completely dried up.
- Wildfires: The drought has been accompanied by record-breaking wildfires. Brazil recorded 11,500 fires in July and 38,000 in August, marking the highest incidence in 20 years.
- Increasing Frequency and Intensity of Droughts.
Causes of Drought:
- Delayed Rainy Season: The rainy season that usually starts in October 2023 began only in January 2024, and was weak.
- Climate Change: Increased global temperatures, along with the El Niño weather pattern, have exacerbated drought conditions.
- Environmental Factors: Sea-surface temperatures in the tropical Atlantic influence rainfall patterns in the Amazon.
- Role of the Intertropical Convergence Zone (ITCZ) in Rainfall: High sea surface temperatures in the tropical North Atlantic can cause the ITCZ to shift northward, leading to less rainfall in the Amazon region.
Impact of Droughts and Wildfire:
- Community Impact
- Navigation Challenges: The drought has led to isolation for Indigenous and riverine communities who rely on waterways for transport and access to essential resources like food and medicine.
- Environmental Consequences of Drought
- Tree Mortality: Droughts lead to higher tree mortality rates, diminishing the forests carbon sequestration capacity.
- Wildlife Impact: Increased animal deaths and a heightened risk of wildfires are significant consequences of prolonged drought conditions
Savannisation
- Pristine savanna is a unique biome that supports a diverse array of life.
- But “savannisation” here refers to when lush rainforest gives way to a drier, open landscape that resembles savanna but is actually degraded forest.
- Local deforestation and global climate changes in temperature and precipitation favour this conversion along the southern and eastern edges of the Brazilian Amazon.
- Deforestation Threshold: The scientific community estimates that savannisation becomes irreversible at 20% to 25% deforestation. Currently, deforestation stands at 17%.
- Arboreal species like monkeys clearly will be impacted by such changes.
