If you ask people what they do for the environment at home, recycling is almost always the first thing mentioned. It is the headline activity, the one with kerbside bins and council leaflets and supermarket loyalty points. Composting, if it comes up at all, is mentioned second, often with a note of mild apology, “I should compost, but…”
The order should probably be reversed. For most households, in terms of what actually reduces emissions, composting matters more than recycling does. Not by a small margin. By a significant one. And the reason is buried in the way landfill works, which most people have never had explained to them. US Composting Council on compost benefits
The landfill problem nobody mentions
When food waste goes to landfill, it doesn’t simply rot. Landfills are designed to bury waste, sealed under layers of soil and plastic, which means there’s no oxygen reaching most of what’s buried. Without oxygen, food waste doesn’t decompose aerobically (producing CO2 and water). It decomposes anaerobically, and anaerobic decomposition produces methane.
Methane is a far stronger greenhouse gas than CO2. Over a 20-year period, it traps about 80 times more heat per kilogram than CO2. Over 100 years, around 28 times more. The difference matters because methane breaks down in the atmosphere over decades, so its short-term warming impact is enormous.
UK landfills now have methane capture systems, pipes that draw the methane up and either flare it (burning it to CO2) or use it for electricity. These systems capture roughly 60 to 75 percent of emissions on average, leaving the rest to escape. So every kilogram of food in landfill that isn’t captured produces a methane equivalent of roughly 50 kilograms of CO2 over its short-term lifetime in the atmosphere.
Compost it instead, aerobic decomposition, and the same kilogram produces essentially CO2 only, much of which is the carbon the food contained anyway and would have released eventually as part of the natural carbon cycle.
How much food a household actually throws away
The UK average household throws away around 100 kilograms of food a year that could have been eaten or composted. WRAP, the waste reduction organisation, puts it slightly higher, closer to 140 kilograms per household when you include trimmings, peelings, and items past their best.
If half of that ends up in landfill (the figure is improving as more councils introduce food waste collection, but it’s still common), that’s roughly 50 to 70 kilograms of food in landfill per household per year. The resulting methane emissions, after capture systems do their best, work out to somewhere between 100 and 200 kilograms of CO2 equivalent annually per household. From food waste alone.
That is more than the average household saves by recycling all of its paper, plastic and glass. By quite a margin.
What recycling actually saves
Recycling does save emissions, of course. Recycling a tonne of aluminium versus producing virgin aluminium saves around 9 tonnes of CO2. Recycling a tonne of paper versus virgin pulp saves about 1.5 tonnes. Glass saves about 0.3 tonnes per tonne recycled. Plastic varies wildly depending on type, from 1 to 2 tonnes per tonne recycled.
The catch is that average households don’t recycle tonnes of anything. The average UK household generates around 400 kilograms of dry recyclables a year, paper, cardboard, plastic, glass, metal. Of that, perhaps half is genuinely recycled (the rest is contaminated, the wrong material, or ends up incinerated). The total annual saving from household recycling, weighted across the mix of materials and capture rates, lands somewhere around 150 to 250 kilograms of CO2 equivalent.
Composting all of your household food waste saves roughly the same, around 100 to 200 kilograms. And here is the key point: the two are additive, not alternatives. Doing both saves more than doing either. But for the household that wants the highest impact for the lowest effort, composting often beats incremental recycling improvements.
A side-by-side, plainly
| Action | Average annual CO2e saved | Effort level |
|---|---|---|
| Recycling everything possible | 150-250 kg | Already automatic for most |
| Composting all food waste | 100-200 kg | Modest, once set up |
| Switching to peat-free compost | 30-50 kg | Low |
| Reducing food waste by 25% | 120-180 kg | Medium |
| Drying laundry instead of tumble drying | 200-400 kg | Medium |
| Flying one fewer short-haul return | 250-400 kg | Lifestyle |
None of these are huge in the global scheme. Together they add up. Composting belongs firmly on the list, comparable to actions that get much more attention.
Why isn’t this more obvious?
A few reasons.
First, the gas itself is invisible. You can see a kerbside recycling truck. You can’t see methane rising from a landfill ten miles away. Recycling is a visible activity; landfill emissions are not.
Second, the council narrative around recycling has been louder for longer. Local authorities have spent thirty years building recycling habits. Food waste collection is comparatively new and not yet universal.
Third, the way food waste decomposes is genuinely confusing. Most people assume that food rotting in landfill produces CO2 (the same as composting), and aren’t aware that anaerobic conditions produce methane instead.
And fourth, composting feels old-fashioned and outdoorsy. Recycling looks modern and council-managed. The cultural marketing has tilted one way.
The other reasons composting matters
The methane case is the strongest single argument, but it isn’t the only one.
Compost replaces bought soil improvers and peat-based products. Peat is dug from peatlands that store enormous amounts of carbon, extracting it releases that carbon over years. Every bag of home compost used means a bag of peat-based compost not bought. UK peat sales are being phased out for amateurs, but transition is ongoing.
Compost reduces the volume of general waste collected. Less weight in lorries means less fuel; smaller landfills means less methane capture infrastructure needed in future.
Compost builds soil. Healthy soils sequester carbon. A garden routinely fed with home compost is, in a small way, holding more carbon in its soil than it would otherwise. The amounts are modest per household but real.
And it changes how you see waste. Once you’re composting, you start looking at your bin differently. The kitchen rubbish becomes mostly packaging, which leads, often, to reducing the packaging too. The systems reinforce each other.
The honest framing
None of this means recycling is unimportant. Recycling matters. It saves real emissions and real raw materials, and it should keep happening. The point isn’t to choose between the two; it’s to notice that composting has been undersold.
If we redesigned home environmental advice from scratch, food waste handling would probably be the second or third item on the list, after reducing flying and switching home heating. It would certainly come before “wash out your yoghurt pots”.
I started composting because my partner was tired of the food waste smell in the kitchen bin. The climate maths came later. The original reason is still valid, the kitchen does smell better, but the bigger reason is that the daily peelings, multiplied by years, multiplied by households, add up to a problem worth solving at the source. Quietly, in a heap at the bottom of the garden, or a bucket under the sink, or a council caddy at the gate. However it gets done, it gets done.
Frequently Asked Questions
Does food in landfill really produce methane?
Yes. Buried under layers in modern landfills, food decomposes anaerobically — without oxygen — and produces methane rather than CO2. Methane is around 80 times more potent than CO2 as a greenhouse gas over 20 years.
How much CO2 does composting actually save?
For an average UK household composting all food waste, roughly 100 to 200 kg of CO2 equivalent per year compared to landfill. The figure depends on local landfill methane capture rates and how much food the household produces.
Is it really more impactful than recycling?
Comparable to it. Recycling saves around 150-250 kg of CO2 per household annually; composting saves 100-200 kg. They're not alternatives — do both — but composting is often undersold relative to recycling.
What about council food waste collection — is that as good as home composting?
Almost as good, sometimes better. Industrial anaerobic digestion captures the methane and uses it for electricity. Industrial in-vessel composting produces standardised compost. Both keep food out of landfill, which is the main point.
Does it matter if I only compost a little?
Yes. The maths is proportional. Composting half your food waste saves roughly half the emissions. There's no threshold below which it doesn't count — every kilogram out of landfill is a kilogram's worth of methane prevented.
What if my council doesn't collect food waste?
You have alternatives — home composting, bokashi, worm bins, community drop-off schemes. The lack of council collection raises the bar slightly but doesn't remove the option. Find a route that fits your home and use it.
