According to a new study published in Science in which scientists used aerial surveys to identify point source emissions from hundreds of waste landfills.
The analysis suggests that while emissions are significantly underreported, they also represent an important mitigation opportunity because many releases persist for months or even years. Aerial observations offer important advantages over current survey approaches that typically involve a worker walking through portions of the landfill with a detector recording locations of elevated surface methane concentrations.
The powerful and invisible greenhouse gas, which has more than 80 times the warming capacity of carbon dioxide during its first 20 years in the atmosphere, is the main component of the fossil gas but is also generated from waste piles when organic materials such as Food scraps break down in the absence of oxygen. Satellites have also helped identify landfills, landfills and waste sites from India to Argentina as methane hotspots.
Scientists in the latest report observed more than 200 active landfills in 18 states that participate in the U.S. Environmental Protection Agency’s greenhouse gas reporting program. They found that 52% of the sites examined had observable point emissions, meaning it was clear this was a direct source of methane.
Methane from landfills makes up about 20% of global gas emissions and is the third largest source after agriculture and fossil fuels attributed to human activity. There are approximately 1,200 open landfills in the United States.