Biogas and Climate Change: The Real Benefits and the Hidden Dangers

The biogas climate change debate spans many considerations. There are undoubtedly many climate-change-reduction benefits that expanding the production of biogas — and the anaerobic digestion process which makes it — will bring. But there are also dangers lurking: produced or managed badly, large quantities of biogas can actually accelerate climate change rather than slow it.

Read on for our balanced view of the biogas climate change benefits and dangers.

First, a few basics worth understanding.

Why is the CO2 from burning biogas said not to warm the planet?

Burning biogas does release carbon dioxide, which contributes to climate change. The crucial difference is that all the carbon in biogas comes from recently living organic material.

That carbon was already part of the fast, natural carbon cycle — plants absorbed it from the air only recently, so returning it does no net harm. What drives global warming is burning fossil carbon that has been locked underground for millions of years and adding it to the atmosphere.

Biogas carbon is quickly replaced by new growth

Because that carbon is reabsorbed by new plant growth — helped along by the nutrient-rich digestate returned to the land — biogas is broadly a carbon-neutral fuel when it is made and used well.

The gas industry has made a determined push to promote “biogas” (also called “biomethane” or “green gas”) as a climate solution. Read that publicity carefully: only genuinely biogenic methane is climate-neutral, not anything derived from fossil natural gas dressed up by association.

So far we have set out the points our readers need to know. Now let us cut through the political rhetoric and get to the facts.

1 – The biogas climate change benefits

The biogas climate change benefits include its ability to reduce methane emissions, cut waste, and provide a useful product in its own right.

Although biogas (and hydrogen) have real potential as energy sources, the gas industry has too often used their existence to mislead the public into thinking fossil natural gas is somehow similar, and therefore benign.

Globally, natural gas companies have leaned on the existence of biogas to suggest, by association, that natural gas is clean and wholesome. It has been something of a smokescreen to extend the life of fossil fuels in our energy system.

Natural gas is a cleaner fossil fuel than coal or oil — but do not let anyone tell you it is a sustainable option to keep burning.

2 – The biogas climate change dangers

Biogas contains methane and must not be allowed to leak

Any serious plan to combat climate change must tackle methane as well as carbon dioxide — otherwise the benefits are easily lost.

Methane is one of the most significant greenhouse gases emitted by human activity. In the United States it accounts for roughly 11–12% of total greenhouse gas emissions, and quantity for quantity it is far more potent than CO₂ over the short term. That share must not be allowed to rise and urgently needs to come down (US EPA, Overview of Greenhouse Gases).

Used properly, biogas capture reduces methane emissions that would otherwise escape from manures and decomposing waste. But all the good done by biogas can be undone if the growing number of businesses and individuals who make and use it allow it to leak invisibly from their plants. Methane is colourless and odourless in the quantities that matter here, which is precisely why leaks go unnoticed without monitoring.

Until recently methane leaks were invisible, but devices are now available that when pointed toward a digester tank pipework and roofing can show leaking biogas in real-time. So it is becoming routine for AD plant operators to commission methane leakage surveys on a regular basis.

The danger from farm biogas plants

Let us be clear: the dangers are not large, but they should not be ignored. Farmers are constantly seeking new income streams while also acting as stewards of the land, and the agricultural community’s commitment to improving farm sustainability is a big reason the on-farm biogas industry matters to rural communities everywhere.

The encouraging news is that regulation is catching up. In Denmark, a 2021 study found average methane loss from biogas plants of around 2.5% — low at large agricultural plants but much higher at some sewage plants. In response, from 1 January 2023 all Danish agricultural, sewage and industrial biogas plants must run a self-monitoring programme and be inspected for leaks once a year by an independent, verified third party (Danish Energy Agency). This is exactly the kind of routine, enforced check the rest of the world should adopt.

For historical context, US on-farm biogas systems were already generating enough renewable energy in 2020 to power roughly 100,000 average American homes — a figure that has grown since and is dwarfed by output in several other nations.

Agricultural biogas must not reduce food output

Agriculture faces rising food demand and a changing climate at the same time. Many climate strategies also lean on farming to store more carbon in soils and to supply feedstock for bioenergy. Anaerobic digestion can help on both counts — by returning nutrient-rich digestate to improve soils and by turning wastes into energy.

But the biogas industry must never be seen to reduce food production, even slightly. The sector should adopt its own good-practice rules to rule out food-production losses, prioritising wastes, residues, manures and sequential crops over purpose-grown food crops.

Policy is already moving this way. Denmark now caps energy crops at just 4% of biogas feedstock from 2025 and prohibits the use of maize, with tighter limits expected. At EU level, the Renewable Energy Directive caps the contribution of food- and feed-based crops towards renewable targets. The direction of travel is clear: biogas should be fed by what would otherwise be wasted, not by the harvest.

The danger of methane leaking from landfills

Keeping organic waste out of landfill is good for the climate. When organic materials rot in landfills, methane is released into the atmosphere. Even the best landfill-gas extraction schemes rarely capture more than about half of the methane produced. Extraction runs while the waste is generating gas at a high rate, then is switched off as volume and quality fall — typically after no more than 20 years — yet buried waste can keep producing landfill gas for a century or more. Diverting that organic material to an anaerobic digester, where the gas is captured in a sealed vessel, is far better for the climate.

Conclusion and recommendations

It is widely accepted that biofuels can contribute to a cleaner global energy mix, but the net climate benefit of bioenergy has real limits that deserve respect.

Improving the efficiency of biogas production, adding new bioenergy sources and expanding others — such as food-waste recycling — will deliver substantial additional output. Even so, few countries will ever match Denmark’s ambition of green gas equal to the bulk of national gas demand.

Some argue biofuels are not sustainable because converting non-agricultural land to grow energy crops can cause a large upfront loss of stored carbon — a so-called “biofuel carbon debt”. We do not see that as inevitable, since approaches such as biochar production can offset such deficits, and a waste-and-residue feedstock strategy avoids the problem altogether.

The biogas industry also needs to keep reducing its own use of fossil fuels for farm machinery and transport. It is doing so, and will continue to improve.

Above all:

• Biogas production need not and never should reduce the production of food for human consumption; industry and governments should legislate against the use of food crops.
• All biogas producers must take great care to prevent accidental methane leakage from facilities of every kind. Governments should set stringent targets to minimise fugitive methane, with routine, enforced inspections — as Denmark now requires.

Anaerobic digestion and biogas are essential to global decarbonisation, but they are not the magic solution many would like them to be.

They are one important technology that every government should be developing as rapidly and fully as possible to counter the climate emergency.

From the archive (2018): Biogas Benefits Essential as Climate-Change Carbon Hits Record High

The section below is preserved from our article first published on 15 August 2018. We have kept it as a historical snapshot because its central argument — that decarbonisation is fundamentally an engineering challenge — has aged all too well. Figures and office-holders named are those of the time.

The biogas benefits of reducing carbon emissions and the effects of climate change became more essential than ever in 2018, as climate-change carbon hit a record high and northern-hemisphere summer heat peaked at temperatures never before recorded.

At the time — two and a half years on from the historic COP21 Paris deal — global carbon emissions were higher than ever.

What is going to force society into action?

The Paris deal was described as a “monumental triumph for people and our planet” by then UN Secretary-General Ban Ki-moon, and as a wake-up call to the industry by then ICE vice-president and long-term climate campaigner Keith Clarke.

“Now we need a revolution in the structure of engineering,” he said.

Because the science tells us it is the level of greenhouse gases in the atmosphere that is unquestionably driving climate change — and that is driven by our carbon-dependent society. Decarbonisation is fundamentally an engineering problem — a civil engineering problem at that. (via New Civil Engineer)

False hope

The three flat years of 2014–16 had raised hopes that emissions had peaked.

Lead researcher Corinne Le Quéré, director of the Tyndall Centre for Climate Change Research at the University of East Anglia, described the rise as “very disappointing”.

“Time is running out to keep warming well below 2°C, let alone 1.5°C,” she warned.

“Last year we saw more evidence of the likely consequences of climate change, with more intense rainfall, higher sea levels and warmer ocean conditions favouring more powerful storms, amplifying the impacts of hurricanes and cyclones.”

“We need to reach a peak in global emissions in the next few years and drive emissions down rapidly afterwards to address climate change and limit its impacts.”

At the time, the annual bill for repairs and recovery following climate-related events was put at US$300bn in the United States alone (via New Civil Engineer). That this figure would rise rapidly has only been reinforced since, in the light of repeated extreme-weather events — an assertion that now appears uncontested.

What is being done to accelerate climate-change action?

One might argue that planners, designers, consultants, engineers and architects should join together globally to offer only the most sustainable, least climate-damaging solutions to their clients. In practice that rarely happens: throughout capitalist economies, professionals work to the “briefs” their clients set. They can advise on lower-carbon design, but it is clients who hold the power to accept higher short-term costs for long-term societal gain.

In reality, professionals can do only so much, and change is not coming fast enough. Yet all hope of holding climate change to tolerable levels is not lost. The pressure is increasingly coming from the financial system itself, rather than from governments — many of which have become more reluctant to subsidise the renewable-energy and waste-to-resource industries (biogas among them) that can help.

A lead on cutting carbon has come from outside the civil engineering profession

Institutional investors are acting to understand and address the risks that climate change poses to their investments. Companies that fail to advise clients on those risks expose themselves to the threat of litigation.

This scrutiny followed an early, high-profile warning from Bank of England governor Mark Carney, in his role as chair of the Financial Stability Board, delivered at Lloyd’s of London in 2015. It spelled out the potential scale and severity of climate-related risks to global financial markets and led to the creation of voluntary, consistent climate-related financial disclosures for companies to use when informing investors, lenders and insurers (via New Civil Engineer).

Looking back from today, that direction of travel has only strengthened. Climate-related financial disclosure has moved from voluntary to mandatory in many jurisdictions, and the civil engineering profession has formalised its own response — the Institution of Civil Engineers now frames reaching net zero as a core duty for the sector it serves. The 2018 call for “a revolution in the structure of engineering” has, in part, been answered.

This is where professionals have a duty to inform their clients about the anaerobic digestion process, and about how the biogas benefits help cut carbon emissions and therefore the effects of climate change. Some of the main benefits are summarised below.

Benefits of anaerobic digestion as an energy producer

Businesses of every kind — agricultural or industrial — can diversify their income by installing anaerobic digestion facilities for their organic waste, or by sending that waste to AD plants. Because the AD process yields an energy source, it is ideally suited to broadening and strengthening a business’s income. Society benefits too, through the reduced carbon emissions that well-implemented projects deliver.

Benefits of anaerobic digestion as a waste-management technique

Running a business more holistically — and avoiding the waste of a resource, namely its organic waste — is one of the important benefits of anaerobic digestion. This matters increasingly to businesses seeking shareholder investment, precisely because of the climate-related risks to those investments described above.

Why the biogas benefits grow more important with each passing year

The biogas benefits of recycling waste material have added a new dimension to waste management. In response, the supportive legal framework being put in place across Europe to harness waste better is a vital boost to the wider biogas industry. Within that circular-economy framework, the large-scale development of anaerobic digestion (AD) and its biogas benefits is an essential component.

AD is not only a renewable energy source. It is also an environmentally friendly, cost-effective way of dealing with much of what we think of as waste.

Waste is a massively underestimated cause of carbon emissions, as the former CIWM President, Professor David C. Wilson, has pointed out:

“One could make a case that better resource and waste management has the potential for reducing GHG emissions across the world economy by 15, 20 or 25 percent, or even more. Such numbers by their nature are ‘guesstimates’, and as such are anathema to climate scientists. However, whatever number we choose to use, the message is still the same. Our sector provides a useful entry point to make very significant contributions to climate mitigation targets. And some of those reductions could be seen as ‘low-hanging fruit’, and/or offer significant reductions over a short timeframe.” (via Don’t Waste Our Climate)

If waste materials are not recycled and are left to decay in landfill, the methane and carbon dioxide they release cannot all be collected, and the remainder escapes into the atmosphere. Worse still is the open burning of waste in backyards where no proper collection exists, as is common in many developing nations. Again quoting the CIWM President, on his own work to measure real emissions from waste:

“…early results suggest that the CO₂ equivalent of black-carbon emissions from uncontrolled burning in backyards in Mexico was 15 times larger than the methane released from the decomposition of equivalent amounts of combustible biodegradable waste disposed at a final disposal site. This suggests that urgent action is needed to reduce domestic open burning of waste, and that this would have a significant impact — both on improving local air quality and respiratory health, and on reducing climate change.” (via Don’t Waste Our Climate)

We would add that those very same backyards could reduce emissions far more effectively if they had the benefits of biogas plants installed in them.

Biogas production can play an important role in reducing emissions from rotting manure, farm wastes and slurries, and in replacing petrochemical-derived artificial fertilisers. In doing so, this proven technology abates significant carbon emissions, and by displacing fossil-fuel energy it greatly reduces climate-damaging greenhouse-gas emissions.

Stop Press! News

What might the 2026 US mid-terms mean for America’s return to global climate targets?

The US mid-term elections of 3 November 2026 were watched closely by anyone who cares about global emissions, because the world’s second-largest emitter had, once again, stepped back from international climate cooperation. Following the second withdrawal from the Paris Agreement and the unwinding of a swathe of federal emissions rules, the direction of US policy had (at the time of writing) reversed sharply from the commitments made in the previous decade.

Early coverage of the result of the US 3 November Mid-Term elections has pointed to a strong Democratic showing, with the party reported to have taken both the Senate and the House of Representatives. At the time of writing the final numbers are still being confirmed, so this should be read as the most likely picture rather than a settled outcome.

It would be easy to assume that a Democratic Congress means an automatic American return to the global carbon-reduction fold. The reality is more constrained, and worth understanding:

• Treaty re-entry is not Congress’s decision. Rejoining the Paris Agreement, setting a new national emissions pledge and steering foreign climate policy are powers that rest with the President and the executive branch, not with the House or Senate. A Democratic Congress cannot, on its own, put the US back into Paris while a reluctant administration holds the White House.
• What Congress can do is control the money and slow the rollback. With majorities in both chambers, the Democrats could protect clean-energy funding, resist the repeal of remaining climate measures, hold departments to account through oversight, and refuse to pass legislation that would entrench fossil-fuel dependence. That is a defensive rather than a transformative role, but it matters.
• The real inflection point is the 2028 presidential election. A full US return to global targets — formal re-entry to Paris, a credible new pledge and the federal rules to deliver it — realistically depends on who occupies the White House from 2029. A strong mid-term result can shape that contest, but it does not decide it.

There is a more durable reason for cautious optimism, however, and it has little to do with Washington. Much of America’s actual decarbonisation is driven by state governments, cities, utilities and private investment, together with the simple economics of cheaper renewables. States such as California have continued to set their own ambitious targets regardless of federal mood, and institutional investors — as we noted earlier in this article — are pricing climate risk whatever the politics of the day.

Our view is unchanged by any single election. A friendlier Congress improves the odds that the US will protect its climate progress and, in time, rejoin the global effort in earnest. But the deeper shift — the one that will actually bring emissions down — comes from the economics of clean energy and from the thousands of local decisions, biogas plants and waste-to-energy projects among them, that carry on regardless of which party holds Capitol Hill.

Help us publicise the benefits of anaerobic digestion and biogas production

Professionals need to inform their clients about anaerobic digestion. Yet the benefits of anaerobic digestion and biogas are still not appreciated by all professional opinion-formers as they need to be, before the technology can realise its potential.

We hope that, in a small way, reading this article has improved your understanding of the biogas benefits in reducing carbon emissions — and therefore the effects of climate change that AD technology can help reduce.

If so, please join us in helping to publicise the potential of anaerobic digestion and biogas-plant development worldwide, for its many climate and societal benefits.

[Archived article originally published on 15 August 2018. Updated content added July 2022. Thoroughly updated and re-verified in November 2026. ]