Climate Change

The Amazon rainforest helps regulate the climate by storing carbon and recycling water. Through photosynthesis, trees and other plants absorb carbon dioxide from the atmosphere and incorporate carbon into their tissues. Some of this carbon remains stored in wood and soils for decades or longer. When forests are cleared, that storage is diminished, and burning or decomposition releases carbon back into the atmosphere. Deforestation therefore contributes to global warming while reducing the forest’s capacity to absorb additional carbon dioxide.

Climate change, in turn, places greater stress on the remaining forest. Higher temperatures increase the atmosphere’s demand for moisture, which can accelerate water loss from vegetation and soils. When water becomes scarce, trees conserve it by closing their stomata—the tiny pores in their leaves through which gases and water vapor pass. This reduces transpiration and also limits the uptake of carbon dioxide for photosynthesis. Prolonged heat and drought can impair growth and increase the risk of tree death.

These changes affect the Amazon’s water cycle. Through evapotranspiration—the combined movement of water into the atmosphere through evaporation and plant transpiration—the forest helps maintain humidity, supports rainfall, and cools the land surface. Forest clearance reduces this moisture supply. Severe drought and further vegetation loss can weaken it even more, creating hotter, drier conditions that leave surviving trees increasingly vulnerable. These interacting pressures are particularly concerning in the southeastern Amazon, where researchers have documented increasing atmospheric dryness.

Deforestation and climate change can therefore reinforce one another. Forest loss releases carbon and disrupts moisture recycling; warming and drought increase stress on the remaining vegetation; and additional tree mortality and fires can release still more carbon. This feedback threatens the forest’s ability to recover from disturbances. A 2022 study found evidence of declining resilience across more than three-quarters of the Amazon rainforest since the early 2000s, with greater losses in drier areas and near human activity. This does not mean those forests have already disappeared, but it indicates that their capacity to recover has weakened (Boulton et al., 2022).

Along the Amazon basin’s western margin, the Andean cloud forests face an additional challenge. Many species occupy relatively narrow elevation ranges. As temperatures rise, the conditions suitable for them may shift uphill. Their survival depends partly on whether they—and the habitats they need—can move quickly enough.

Having higher ground available does not guarantee that suitable habitat will develop there. Research in the Peruvian Andes found that the boundary between cloud forest and high-elevation grassland moved uphill far more slowly than would be necessary to keep pace with projected warming. Grazing and human-set fires further restricted its movement. Forest species may consequently lose suitable habitat at lower elevations without gaining enough at higher elevations, increasing the risk of population declines and extinctions (Lutz et al., 2013).

Protecting the Amazon requires addressing both forest destruction and global greenhouse gas emissions. Conserving forests protects stored carbon and the water cycle, while limiting warming reduces the climatic pressures that threaten their survival.

References:

Coe, Michal T. Rattis, Ludmila. Machado, Manoela. Macedo, Marcia N. Fiske, Gregery J. Amazon deforestation and fire outlook Woodwell Climate Research Center

https://www.woodwellclimate.org/project/amazon-fire-outlook/

McKee, Jenny. (March 8, 2022) The Amazon Could Soon Transition to a Dry, Savanna-like Ecosystem A new study shows that more than 75 percent of the rainforest is losing its ability to recover from droughts and fires—a finding with huge consequences for humans and wildlife alike. Audubon

https://www.audubon.org/news/the-amazon-could-soon-transition-dry-savanna-ecosystem

Climate Change Threatens Andean Cloud Forests Amazon Aid

https://amazonaid.org/climate-change-threatens-andean-cloud-forests/