Recent research is challenging long-held assumptions about landfill methane emissions. Measurements at individual sites are showing that emissions can vary substantially over time and, in some cases, differ significantly from conventional estimates.
For landfill operators, the most important question may not be whether methane emissions are higher than expected, it is why.
At one New Jersey landfill, researchers used approximately two-and-a-half years of continuous measurements, supported by aircraft observations, to estimate that 2023 methane emissions were about five times higher than the amount reported to EPA. They also documented substantial seasonal and weather-related variability, including higher emissions during colder conditions and periods of falling barometric pressure.
The study does not mean every landfill is underestimating emissions by a factor of five. It does reinforce a practical point for operators: a periodic measurement provides only part of the picture.
Our ability to measure and understand landfill gas is changing quickly. And regulators, researchers and nearby communities are paying attention.
But for the landfill, the harder question is not “Are methane emissions higher than expected?” It is “Why is methane rising in the first place?” and, arguably more important, “What do I do about it?”
Is the gas collection system out of balance? Has liquid built up? Did cover conditions change? Did waste placement shift? Is equipment underperforming? Is weather changing how gas moves through the site?
Source: Onterris
That is why landfill gas is such a useful test of environmental maturity. Measuring methane is just the beginning.
More mature landfill programs do not stop at confirming the methane result. They work backward to determine what changed in the waste mass, cover, gas collection system or site operations and whether those conditions are connected.
Let’s explore how.
What an elevated methane reading doesn’t tell you
Elevated methane readings reveal a problem, but they do not necessarily say what the problem is. And there isn’t a standard playbook to figure it out. Every site is unique.
A typical response might look like this. There is a spike in methane or an odor complaint. The immediate response is often appropriate: confirm the result, inspect the area, review the wellfield, evaluate the cover and document the corrective action. The weakness comes when the same response is repeated without determining why the condition keeps returning.
But what happens if methane readings keep rising or odor complaints keep coming in?
Instead of focusing too quickly on the symptom, teams should ask what changed across the landfill.
Has waste placement changed recently, or maybe it needs to change? Are gas, condensate and leachate systems being considered together and in how they interact? Are changes in site design or system design needed because of changing weather patterns?
And ideally, these questions start to be asked proactively, before a problem ever occurs. The goal is not more monitoring for its own sake, but instead a clearer path from signal to action.
The data often exists. The connection doesn’t
At most landfills, the information needed to understand a gas problem already exists.
The issue is that it rarely lives in one place.
Landfill gas does not fit neatly inside one department, even when one person is wearing several hats. At a smaller landfill, the same person may be reviewing methane data, coordinating liquids or cover work, checking collection equipment and handling odor calls. At a larger site, those same signals may sit across environmental, operations, maintenance, community relations, finance and leadership teams.
Individually, the data may not look unusual. Everyone is busy, and working on things that genuinely matter, but the dots are not being connected around the bigger picture.
The good news is that many operators may not need to start with more monitoring or a major technology investment. The first step is often process change, bringing existing data together, aligning teams around common goals and creating regular review cadences that make it easier to spot patterns across the site.
The first improvement may not be another monitoring platform. It may be a disciplined operating review that puts gas data beside liquid levels, waste-placement records, cover observations, maintenance history, weather conditions and complaints. The objective is to identify recurring relationships that individual teams may not see on their own.
More frequent measurement and investment in new systems can come later.
The costs often appear before enforcement
A landfill gas problem does not need to become a notice of violation (NOV) before it starts costing the site money and attention.
Unresolved gas conditions can raise emissions and odor, increase field time, create contractor calls, strain collection system performance, draw regulator questions and put the site in front of nearby residents for the wrong reasons.
The common theme is that, on their own, none of these may look significant. Over time, however, they can compound and eventually become a capital, permitting or reputational issue.
The earlier a team can connect these leading indicators of environmental risk back to the underlying system, the more options it has to intervene before the problem becomes more expensive or harder to explain.
Methane emissions are more public than ever
Landfill methane is easier for outside parties to see. Satellite, aircraft and other remote-sensing technologies give regulators, researchers, communities and nongovernmental organizations more ways to identify potential emissions without relying solely on site-reported data.
A 2025 high-resolution satellite study of 60 North American municipal solid waste landfills reported 457 methane plumes across 697 site observations from 2021 to 2024.
Remote sensing adds valuable independent information, but it has limits. Aircraft and satellite observations are typically snapshots, and timing, wind and atmospheric conditions can affect results. They can identify a potential emission event, but they cannot explain the cause on their own.
That makes site-level context essential. When outside data identifies a plume, the operator needs to reconstruct what was happening at the landfill, evaluate likely causes, document the response and determine whether the corrective action worked.
What environmental maturity looks like in practice
A strong landfill gas program does more than collect readings or respond to individual exceedances. It connects gas performance with liquids, cover, waste placement, maintenance, weather and operating decisions.
Rather than requiring perfect data, it requires the discipline to ask what changed, bring the right people into the discussion and verify whether the response worked.
Methane may be the first visible signal, but it is rarely the whole story. The ability to understand that signal and act before it becomes a larger operational, regulatory or community issue is a meaningful test of environmental maturity.
