Amazon Trees Grow Larger Amid Climate Change, Study Finds

Sep 27, 2025, 3:13 AM

Hover over text to view sources

Trees across the Amazon rainforest are growing larger in response to rising carbon dioxide levels, according to a major study published in Nature Plants. Researchers found the average size of trees in the Amazon has increased by 3.2% every decade for at least the past 30 years, with both large and small trees showing growth trends . This phenomenon is attributed to the "fertilizing effect" of higher CO2 concentrations, which enhances plant growth by providing more resources for photosynthesis .

The study, led by an international team of over 100 scientists from 60 universities, analyzed data from 188 permanent forest plots across the Amazon. Monitoring began in 1971 and spanned decades, revealing that trees have thickened their trunks by 3.3% per decade since the 1970s . Professor Beatriz Marimon of Universidade do Mato Grosso noted that even the largest trees in intact forests have thrived despite climate threats, highlighting their resilience to environmental stressors .

The findings suggest that rising CO2 levels are driving a "benefits shared" response, where all tree sizes benefit from increased atmospheric carbon. This contrasts with earlier hypotheses that only larger trees would dominate under higher CO2 conditions. Dr Adriane Esquivel-Muelbert of the University of Cambridge emphasized that the results underscore the critical role of tropical rainforests in mitigating climate change, as large trees absorb significant amounts of CO2 from the atmosphere .

However, researchers caution that these benefits are not without risks. While the study shows no declines in tree basal area, the long-term effects of climate change, such as heat stress, water scarcity, and wildfires, could reverse these trends. Dr Rebecca Banbury Morgan of the University of Bristol warned that deforestation remains a major threat, as old trees provide far greater carbon and biodiversity benefits than newly planted ones . The study also highlights that fragmented forests in the Amazon have shifted from carbon sinks to sources, exacerbating the climate crisis .

The research team emphasized the importance of preserving intact forests to maintain their carbon sequestration capacity. "These results underscore just how important tropical rainforests are in our ongoing efforts to mitigate against man-made climate change," Esquivel-Muelbert said . However, the study also reveals that the Amazon's ability to absorb carbon has weakened in recent years due to deforestation, habitat degradation, and climate impacts like frequent droughts and fires .

While the findings offer hope for the Amazon's resilience, experts stress that the situation remains precarious. The study's authors call for urgent action to protect remaining pristine forests and address the root causes of climate change. As Brazil plans infrastructure projects that could further fragment the Amazon, the balance between carbon absorption and emissions remains a critical concern for scientists and policymakers alike .

Meta-Analysis Reveals Self-Other Discrepancy in Climate Risk Perception

A recent meta-analysis involving over 70,000 participants across 17 countries highlights a significant self-other discrepancy in climate change-related risk perceptions. The findings indicate that individuals tend to perceive their own risk of climate impacts as lower than that of others, which may hinder climate action efforts.

Earth's Carbon Sinks Face Climate Feedback Loops

Climate change is undermining Earth's natural carbon sinks, with feedback loops contributing to rising CO2 levels. Scientists warn that warming extremes and human activities are reducing the capacity of forests, oceans, and soils to absorb greenhouse gases, creating a dangerous cycle of accelerated global heating.

Transforming Extreme Weather Tragedies into Climate Victories

Extreme weather events are increasingly becoming catalysts for climate activism and policy change. By leveraging the immediate impacts of disasters, communities can unite to demand accountability from fossil fuel companies and push for legislative reforms. Successful examples from Vermont, the Philippines, and Spain illustrate how grassroots movements can turn tragedies into victories for climate justice.

Debate on Climate Change: Facts vs. Opinions

The discourse surrounding climate change is marked by a clash between scientific consensus and public opinion. While many scientists assert that human activities are the primary drivers of climate change, some public figures and commentators express skepticism, leading to a complex debate about the urgency of action and the role of corporate interests.

The Human Impact on Climate Change: A Call for Optimism

John Coleman argues that while human activities significantly contribute to climate change, there is a growing global consensus on the need for action. He emphasizes the importance of recognizing widespread public support for climate initiatives and the potential for innovative solutions to mitigate environmental impacts.