A recent study conducted by scientists has shed light on the concerning levels of methane emissions emanating from landfills across the United States. The study, published in the journal Science, involved aerial surveys of over 200 landfills in 18 states from 2018 to 2022, making it the most extensive measurement-based survey of American landfills to date.
Methane, a potent greenhouse gas with over 80 times more warming power than carbon dioxide in the short term, is primarily produced by sources such as oil and gas and agriculture. While landfills are often overlooked as a significant methane source, they contribute approximately 20% of global human-caused methane emissions.
Landfills generate methane when organic waste decomposes without oxygen, providing an ideal environment for methane-producing bacteria. The study highlighted that the current method of measuring methane emissions at landfills, which involves walking surveys using handheld sensors, may not provide accurate data due to safety concerns and limited coverage.
The scientists emphasized the importance of advanced monitoring systems, such as remote sensing from aircraft, drones, and satellites, for more precise and comprehensive methane detection. Using airborne imaging spectrometers, methane plumes were detected at 52% of the landfills surveyed, surpassing detection rates in the oil and gas sector.
The study revealed that average methane emissions from landfills were 1.4 times higher than officially reported to the Environmental Protection Agency's Greenhouse Gas Reporting Program. Furthermore, landfill methane emissions were found to be more persistent than those from oil and gas production, with 60% lasting for multiple months or even years.
Experts, including Professor Rob Jackson from Stanford University, described landfills as 'super-emitters' of methane. They emphasized the urgent need to address methane emissions from landfills, as reducing methane is considered one of the most effective strategies to combat climate change due to its high warming potential.
Despite the challenges posed by landfill emissions, the study highlighted the necessity of prioritizing methane reduction efforts in waste management alongside the oil and gas industry. Scientists underscored that even in a future less reliant on fossil fuels, waste generation will persist, necessitating sustainable waste management practices to mitigate methane emissions and their impact on the climate.
