New aircraft based research has found that methane emissions from the Amazon rainforest’s wetlands are significantly higher than current climate models predict, raising concerns about the accuracy of global climate projections.
The study, led by researchers from the Max Planck Institute for Chemistry and published in Geophysical Research Letters, found that methane emissions in some parts of the Amazon are up to four times higher than existing estimates. Scientists said the findings highlight major gaps in understanding greenhouse gas emissions from tropical wetlands.
Methane is one of the most powerful greenhouse gases and has seen a sharp rise in atmospheric concentration in recent decades. While wetlands are the world’s largest natural source of methane, estimating emissions from tropical regions has remained difficult due to limited ground observations and persistent cloud cover that hampers satellite monitoring.
Researchers conducted low altitude measurement flights over the Brazilian Amazon between December 2022 and January 2023 using the HALO research aircraft. Flying as low as 200 metres above the forest canopy, the team collected more than 7,000 methane measurements across the region.
The observations showed that methane concentrations near the Earth’s surface were, on average, about twice as high as model estimates, while measurements at higher altitudes closely matched existing climate models. Scientists said this indicates that current models accurately simulate atmospheric transport but significantly underestimate methane released from the ground.
The study identified Amazon wetlands as the primary source of the missing methane. Emissions were estimated to be 26 per cent higher from river deltas 19 per cent higher from reservoirs and 13 per cent higher from regularly flooded river areas than previously calculated.
Researchers noted that the measurements were taken during the transition between the dry and wet seasons a period with minimal biomass burning, allowing them to capture methane emissions largely unaffected by human activities.
Lead author Linda Ort said the findings reveal that many methane sources in tropical wetlands remain underestimated and stressed the need for more field measurements to improve climate and Earth system models.
According to the researchers, around 65 per cent of global methane emissions come from human activities such as agriculture, fossil fuel production and waste management, while the remaining 35 per cent originate from natural sources, mainly wetlands.
The research team called for expanded monitoring across other data poor tropical regions, including Central Africa and Southeast Asia to better understand the global methane budget and strengthen future climate projections.