Recent research from the Max Planck Institute for Meteorology (MPI-M) challenges long-held assumptions about the Amazon rainforest’s vulnerability to rainfall disruption caused by deforestation. Published in Geophysical Research Letters, the study reveals that the Amazon may maintain stable annual rainfall levels even under extreme deforestation scenarios.
Scientists have long considered the Amazon as “the lungs of the Earth” due to its biodiversity and role in carbon storage and climate regulation. The prevailing theory suggested that deforestation would severely disrupt the evapotranspiration process—where plants transfer moisture from soil to atmosphere—creating a dangerous feedback loop that could push the ecosystem past a “tipping point” where the rainforest would irreversibly transform into savannah.
These earlier predictions relied on oversimplified climate models that either used global climate models inadequately representing convection (the atmospheric mechanism crucial for rainfall), or employed regional models that couldn’t account for how large-scale atmospheric circulation might adapt to deforestation.
Researchers Arim Yoon and Cathy Hohenegger employed the global storm-resolving ICON model, which directly resolves atmospheric convection with unprecedented precision. Their simulation ran globally for three years at a detailed 5-kilometer resolution—significantly more advanced than previous research methods.
The study revealed that rainfall in the Amazon isn’t primarily determined by evapotranspiration as previously believed. Instead, large-scale atmospheric circulation significantly compensates for moisture loss due to deforestation. “The wind at about three kilometers altitude carries enough moisture from the ocean into the region to make up for the decline in evapotranspiration,” explained Yoon. The calculations showed little to no change in annual rainfall, even under complete deforestation conditions.
Despite stable annual precipitation totals, the research identified important changes in seasonal rainfall distribution throughout the year. “Just using one indicator to assess the future of the Amazon rainforest isn’t enough. The details of the rainfall patterns can make a big difference,” noted Yoon. These seasonal variations could significantly impact ecosystem health, agriculture, and communities dependent on predictable rainfall patterns.
MPI-M scientists plan to refine their analysis by examining whether extreme rainfall events or prolonged droughts might increase under deforestation conditions. Understanding these patterns will provide critical insights into real-world impacts.
While the research suggests greater rainfall resilience than previously thought, it doesn’t diminish the severe ecological consequences of deforestation. Even with stable total rainfall, deforestation disrupts ecological balance through habitat loss and altered seasonal precipitation patterns, threatening biodiversity and human communities dependent on the Amazon. The findings invite scientists to revisit previous assumptions about land precipitation sensitivity and develop more nuanced models of climate-vegetation interactions in critical ecosystems like the Amazon rainforest.
https://www.earth.com/news/amazon-rainforest-may-be-much-more-stable-than-we-thought