In simple terms
Methane is the simplest hydrocarbon: one carbon atom bonded to four hydrogen atoms, written CH4. It is colorless and has no smell of its own, so gas suppliers add one.
It is the main ingredient of natural gas. It is also a greenhouse gas, meaning it traps heat that would otherwise leave the planet.
How it works
Methane absorbs infrared heat radiating from the surface. Weight for weight it traps about 80 times more heat than carbon dioxide over a 20 year period.
It does not linger. Methane breaks down in the atmosphere in roughly a decade, while carbon dioxide lasts for centuries. That short life is why cutting methane shows up in the climate quickly.
Levels are measured in parts per billion. NOAA recorded 1,921.79 ppb in 2024, up from 1,915.73 ppb the year before.
Countries do not all score it the same way. Most national greenhouse gas reporting uses a 100 year comparison with carbon dioxide, which gives a far smaller multiplier than the 20 year figure. The same tonne of methane can therefore look very different in two official documents.
Why it matters
The UN Environment Programme attributes roughly a third of the warming the world is feeling today to methane.
Methane also feeds ground-level ozone, a pollutant linked to about a million premature deaths a year and to lost crop yields.
Because the gas is worth money, many leaks can be sealed at low or even negative cost, which is why methane is treated as the fastest available brake on warming.
Where you’ll see it
- Gas stoves, boilers and pipelines, where methane is simply the fuel.
- Livestock digestion and flooded rice fields, the largest farm sources.
- Landfills and wastewater treatment, where waste rots without oxygen.
- Satellite reports naming large leaks at oil and gas sites.
Example
A satellite spots a methane plume drifting from a gas field. Engineers trace it to a leaking valve and close it, which cuts emissions and saves gas the operator can sell.
Often confused with
Methane is a single gas. Natural gas is the mixture sold to customers, mostly methane but with other hydrocarbons and impurities mixed in.
Key facts
- Methane is the primary component of natural gas and a potent greenhouse gas.1
- Methane is responsible for approximately a third of the warming the world is experiencing today.1
- Methane stays in the atmosphere for about a decade but traps roughly 80 times more heat than carbon dioxide over a 20 year period.1
- Human-driven methane comes mainly from agriculture, about 40 percent, fossil fuels, about 35 percent, and waste and wastewater, about 20 percent.1
- NOAA measured atmospheric methane at 1,921.79 parts per billion in 2024, up from 1,915.73 ppb in 2023, making it the second largest human-emitted contributor to global warming.2
Related concepts
In the news
Quick checkWhy does cutting methane affect the climate faster than cutting carbon dioxide?Show answer
Methane breaks down in the atmosphere in about a decade, while carbon dioxide persists for centuries, so reductions in methane show up in the atmosphere much sooner.
Sources
- UN Environment Programme. Facts about methane. Undated (accessed 18 September 2026)
- NOAA Climate.gov. Current greenhouse gas levels. Undated (accessed 18 September 2026)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed September 21, 2026Researched and drafted with AI assistanceReport an issue