Landfill gas is closely linked to climate change because of its methane content. Methane is a highly effective heat‑trapping gas in the short term, so even relatively small emissions can have a large impact on the climate. When landfill gas escapes into the atmosphere instead of being captured, it becomes one of the most important greenhouse‑gas emissions from the waste sector.
Unlike carbon dioxide from burning fossil fuels, the methane in landfill gas comes from recently produced organic waste such as food, paper and green waste. That means it is part of a relatively short carbon cycle. However, as long as methane is released to the atmosphere, it still contributes to global warming. Capturing and destroying or using landfill gas is therefore a key climate‑mitigation measure in modern waste‑management policy.
Why methane is so important
Methane has a much higher warming effect than carbon dioxide over the first couple of decades after it is emitted. It does not stay in the atmosphere as long as carbon dioxide, but during its lifetime it traps significantly more heat. This makes early and effective control of methane emissions from landfills particularly valuable for near‑term climate goals.
Because landfills can continue to generate gas for decades, unmanaged sites can be a persistent source of methane. Installing gas collection systems early in the life of a landfill and maintaining them into the aftercare period helps to reduce cumulative emissions. This is why regulators increasingly focus on optimising gas capture efficiency, not just on having infrastructure in place.
Flaring landfill gas
Flaring is often the first and simplest way to reduce the climate impact of landfill gas. In an enclosed flare, methane in the gas is combusted and converted mainly into carbon dioxide and water vapour. While carbon dioxide is still a greenhouse gas, the overall warming effect is significantly lower than if the methane had been released unburned.
Modern flares are designed to achieve high combustion efficiency and to operate safely even when gas flows and methane concentrations fluctuate. They are usually used in three situations:
- Early in the life of a site, before energy‑recovery plant is installed.
- On smaller or declining sites where utilisation is not economically viable.
- Alongside energy‑recovery systems, to manage excess gas or downtime.
Using landfill gas for energy
When conditions are suitable, using landfill gas as a fuel can deliver both climate and energy benefits. Common options include:
- Electricity generation using gas engines or turbines, sometimes coupled with heat recovery for nearby buildings or processes.
- Combined heat and power (CHP) units, which maximise the useful energy recovered from the gas.
- Upgrading to biomethane by removing carbon dioxide and trace contaminants so that the gas meets pipeline or vehicle‑fuel standards.
By displacing fossil fuels such as natural gas, oil or coal, well‑managed landfill gas utilisation projects can reduce net greenhouse‑gas emissions. The climate benefit comes from two effects working together: avoiding methane emissions from the landfill and avoiding emissions from the fossil fuels that are no longer needed.
Residual emissions and limitations
Even with well‑designed systems, it is difficult to capture 100% of the gas generated at a landfill. Some emissions may occur before collection systems are installed, from the landfill surface between wells, or after gas yields fall too low for active extraction to be viable. These diffuse emissions can still contribute to climate change.
Because of these limitations, many countries now combine landfill gas control with policies that reduce the amount of biodegradable waste going to landfill in the first place. Measures such as separate food‑waste collection, composting, anaerobic digestion and waste‑to‑energy plants all help to cut the long‑term potential for landfill gas generation.
Relevance for the UAE
For the UAE, the climate role of landfill gas links directly to broader decarbonisation and sustainability strategies. Existing landfills containing high proportions of organic waste are likely to be significant methane sources unless they are actively managed. Capturing gas from these sites and either flaring it or using it for energy can offer a relatively quick way to reduce emissions.
At the same time, new waste‑to‑energy facilities and increased diversion of organics can limit the amount of future waste that ends up in landfill. For clients and decision‑makers, understanding how landfill gas contributes to climate change, and how capture and utilisation can mitigate this, supports more informed choices about investment, regulation and technology deployment.