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U.S. landfills emit an exorbitant amount of methane into the atmosphere

As trash decomposes in landfills, it releases a very potent greenhouse gas called methane. During the first 20 years following its emission, methane has a global warming potential (GWP) that is more than 80 times greater than that of carbon dioxide, meaning it traps substantially more heat in the Earth’s atmosphere.

Landfills alone account for a substantial chunk of human-caused methane emissions in the United States. Their combined impact can be compared to adding the yearly greenhouse gas emissions of nearly 23 million gas-powered cars to the atmosphere.

The problem is, getting accurate measurements of landfill methane has been a real challenge. Scientists often rely on models and estimates, but they haven’t been able to study the direct emissions from many individual landfills…until now.

Methane leaks from landfills

Carbon Mapper, a non-profit, led the largest-ever direct survey of U.S. landfills. They teamed up with top scientists from NASA’s Jet Propulsion Laboratory (JPL), Arizona State University (ASU), and even the Environmental Protection Agency (EPA).

Armed with cutting-edge aircraft, the team swooped in to gather real-time data on landfill emissions.

Point source methane in landfills

The study revealed that point source emissions, which are concentrated releases of methane from specific areas within a landfill, were present in over half of the surveyed landfills.

This rate of concentrated methane leakage is significantly higher than the leak rates commonly observed in the oil and gas industry.

Persistent pollution

Unlike oil and gas leaks, which often get patched up quickly, landfill leaks can be stubbornly persistent. The study revealed that 60% of landfills with leaks were spewing methane for months or even years. These continuous leaks account for the lion’s share of landfill emissions.

Reported methane emissions

The team discovered a big mismatch between their measured emissions and what landfills officially reported to the government. In many cases, the actual pollution levels were much higher than reported, suggesting that our current reporting methods are missing major methane culprits.

Tackling methane mess from landfills

“Addressing these high methane sources and mitigating persistent landfill emissions offers strong potential for climate benefit,” said Dr. Dan Cusworth, Carbon Mapper Program Scientist and lead author on the paper.

So, how do we tackle this methane mess? It starts with better detection. Traditional ground-level surveys, where workers walk around with handheld methane sensors, simply aren’t cutting it.

Hence, advanced tech like satellites, aircraft, and drones could help in painting a complete picture of which landfills are leaking and exactly where the leaks are located.

Carbon Mapper is determined to be at the forefront of change. Their satellite initiative, scheduled for launch in 2024, is designed to track landfill emissions all over the world. Furthermore, this vital data will be freely available to landfill operators, policymakers, and the public.

Impact of methane from landfills

As discussed above, methane emissions have a profound impact on our planet, primarily contributing to climate change due to their potent greenhouse effect.

Methane (CH4) is over 28 times more effective than carbon dioxide (CO2) at trapping heat in the atmosphere over a 100-year period, making it a significant driver of global warming.

Acceleration of climate change

Methane’s high potency as a greenhouse gas means that even small amounts can have a large impact on Earth’s temperature. Its release from sources like landfills, agriculture (particularly from the digestive processes of livestock), and the production and transport of coal, oil, and natural gas significantly accelerates the rate of climate change. This leads to more extreme weather conditions, such as heatwaves, droughts, and severe storms, affecting ecosystems, human health, and food security.

Formation of ground-level ozone

Methane also contributes to the formation of ground-level ozone (smog), a harmful air pollutant. While ozone in the stratosphere protects life on Earth from the sun’s ultraviolet rays, at ground level, it can cause respiratory issues, aggravate lung diseases like asthma, and reduce lung function. This not only affects human health but also can reduce agricultural productivity by damaging crops.

Shorter atmospheric lifetime, big impact

Despite methane having a much shorter atmospheric lifetime than CO2 (about 12 years compared to centuries for CO2), its immediate impact on climate change is much stronger. This means that actions taken to reduce methane emissions can lead to relatively quick climate benefits, making methane reduction a critical part of strategies to limit global warming in the short term.

Positive feedback loops

Methane emissions are part of several positive feedback loops that can exacerbate climate change. For example, melting permafrost due to rising global temperatures can release massive amounts of methane trapped in ice, leading to even more warming and further permafrost melt. Similarly, drying wetlands release methane that was previously absorbed by wet soils, contributing to more warming.


Climate change driven by methane emissions poses a significant threat to biodiversity. Changing temperatures and weather patterns disrupt habitats, forcing species to migrate, adapt, or face extinction. This loss of biodiversity can destabilize ecosystems, affecting ecosystem services like pollination, water purification, and disease control that are vital for human survival.

What can you do to reduce landfills methane?

In facing the daunting challenge of reducing landfill emissions, let’s remember this: individual actions, multiplied across our communities, create a groundswell of change.

The key to tackling this issue lies in the choices we make every day, and our willingness to demand better systems. So, here’s how each of us can be part of the solution:

Embrace waste management as a lifestyle

“Reduce, Reuse, Recycle…and Compost!” It’s not just a catchy phrase, it’s your toolkit. By mindfully reducing what we buy, creatively reusing items, and diligently recycling, we slash the amount of trash heading to the landfill.

And composting? It’s a game-changer. Food scraps and yard waste are major landfill culprits, but they can become rich soil instead. Home composting or using a local program keeps this stuff out of landfills and puts it to good use.

Advocate as loudly as you recycle

Individual action is powerful, but to truly transform how we deal with waste, we need bigger changes. Support policies that require better landfill monitoring and force methane reductions.

Contact your representatives, make your voice heard at town halls, and back groups fighting for a cleaner future.

Spread the word, it’s contagious

Talk to friends and family about the surprising impact of landfill emissions. Share what YOU do to make a difference, and encourage them to join in.

Post about it, blog about it, shout it from the social media rooftops. Awareness leads to better choices and a whole lot more people taking action for a healthier planet.

Change starts with understanding. Now that you know about the hidden pollution coming from landfills, let’s work together towards a cleaner, more sustainable future.

The study is published in the journal Science.


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