The hidden methane threat fueling climate change

In a startling revelation, scientists reveal the hidden truth behind America’s landfills: They are not just landfills, but powerful sources of methane emissions, with 1,200 sites emitting far more than previously recognized. This methane, which traps 80 times as much heat as carbon dioxide, worsens climate change. With landfills ranking third in methane pollution, urgent action is imperative. As researchers advocate for waste reduction and innovative solutions such as waste-to-energy plants, the call to rethink our approach to waste management is growing louder.

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By FD Flam

Every year, Americans dump more than 250 million tons of waste into landfills, where it seems to magically disappear from our lives. In reality, our waste is fossilized or digested by huge populations of methane-emitting bacteria. ___STEADY_PAYWALL___

Over 20 years, each pound of methane emitted has 80 times the heat-trapping capacity of the same amount of carbon dioxide. (CO2 lasts in the atmosphere much longer.) And our nation’s 1,200 landfills produce more methane than we thought, according to a group of scientists who recently used an airborne remote sensing system to fly more than 200 of them. They measured methane gas emissions 1.4 times as much as officially recognized by the Environmental Protection Agency. The journal Science published their findings in March.

These revelations underscore that fighting climate change requires reducing or phasing out landfills. That would not only deliver a huge reduction in greenhouse gas emissions, but also prevent swaths of land from being swallowed up by the growing landfill industry.

The new measurements confirm recent estimates made by his group, said Professor Nickolas J. Themelis of Columbia University. By his estimate, U.S. landfills emit about 10 million tons of methane per year — creating a greenhouse gas equivalent to 800 million tons of CO2 over the next 20 years. That’s an amount comparable to what the airline industry produces, he said.

Although oil and gas production and agriculture are the largest sources of methane pollution, landfills come in a close third, says the Science study’s lead author, Dan Cusworth, a climate scientist at the University of Arizona and project scientist for the non- profit organization Carbon Mapper.

Until recently, the only direct methane measurement scientists could make at a landfill was to send a brave soul walking around on top of it, he said. This was far from systematic.

“Landfills are very complex, dynamic environments,” he said. There are hills and even cliffs. “You can imagine the area where waste is actively being dumped – it’s too dangerous for anyone to walk there.” So most previous research into landfill emissions was based on mathematical models – which, it turned out, underestimated the problem. Using a technique called aerial spectroscopy, Cusworth’s group could better measure emissions from each landfill.

While Cusworth’s research reveals the true extent of the problem, people have known for decades that landfills produce methane, says Sally Brown, a professor at the University of Washington and one of the world’s experts on the secret life of landfills and their contribution to climate change. .

When biodegradable material decomposes above ground or in compost piles, bacteria digest it with the help of oxygen, creating carbon dioxide. But when your food waste ends up among 80 tons of other waste, bacteria resort to a different, oxygen-free (anaerobic) process that produces a lot of methane.

In the past, when waste went to a regular landfill, these emissions could pose a fire hazard. Public safety concerns led the EPA to require that city landfills be replaced with “sanitary landfills” with a honeycomb structure of cells lined with clay.

“They had to start collecting gasoline,” she said, “so it doesn’t go into Joe Schmo’s basement and blow him up when he has a cigar.”

Today, concerns about climate change should prompt a similar reconsideration of landfills. Pipes coming from the cells can divert some of the methane, Brown said, where it can be used for energy or burned.

Then there are waste-to-energy plants. Although uncontrolled combustion is a major source of air pollution, a well-designed, modern waste-to-energy facility captures most heavy metals, dioxins, particulates and other impurities. In 2006, Beijing, China, was surrounded by 500 landfills, Columbia’s Themlis said, and since then they’ve started putting most of their waste into waste-to-energy plants.

The plants still emit carbon dioxide and some people have protested their construction in their neighborhoods, but Denmark and Japan are already using them to phase out landfills — along with strategies like cutting down on waste and getting better at recycling.

“You know, I see Elon Musk talking about spending money to populate Mars,” Themelis said. “It’s so absurd… while at the same time we are transforming a large area of ​​green earth into landfills every year.”

There are also small things each of us can do to reduce the problem. Most of the methane in landfills comes from food waste, Brown said, and in the U.S., much of that is edible food. By some estimates, as much as 30% of the food we produce ends up in landfills instead of on our tables.

That’s an easy fix: Seattle has already significantly reduced food waste thanks to better public awareness and systems to get edible food to food banks. Brown said Alameda County, California, still has a good system for keeping food waste out of landfills.

Another way to get rid of food waste is to turn it into animal feed. Over our Zoom link, Brown showed me a gadget she has at home that dehydrates food waste and turns it into chicken feed. “We give it to our neighbor,” she said. In return, the neighbor shares the eggs. Near Las Vegas, there is a program that diverts food waste to feeding pigs.

Whatever waste remains, we will have to make smart decisions. Trash-to-energy plants are not perfect, but probably have less impact on the climate than landfills. After all, waste does not simply disappear

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