Two gases do most of the warming, and they behave nothing alike.
One is a slow, relentless accumulator; the other is a short-lived but intense burst. Understanding the difference is key to understanding climate strategy.
TL;DR
- CO2 has contributed more than 60 percent of the warming to date and lasts in the atmosphere for centuries.
- Methane caused about 0.5°C, roughly 30 percent, of observed warming from recent emissions, but lasts only about 12 years.
- Methane is far more potent per tonne, with a warming effect 28 to 36 times CO2 over 100 years and 84 to 87 times over 20 years.
The comparison here draws on the IPCC’s Sixth Assessment Report, NOAA, and the IEA’s methane analysis.
Two gases, two very different profiles
| wdt_ID | wdt_created_by | wdt_created_at | wdt_last_edited_by | wdt_last_edited_at | Property | CO2 | Methane |
|---|---|---|---|---|---|---|---|
| 1 | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | Share of warming | more than 60% | about 30% |
| 2 | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | Atmospheric lifetime | centuries | ~12 years |
| 3 | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | Potency vs CO2 (100 yr) | baseline | 28 to 36 times |
| 4 | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | Potency vs CO2 (20 yr) | baseline | 84 to 87 times |
| 5 | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | emmanuel-ashemiriogwa | 06/08/2026 10:11 AM | Concentration vs pre-industrial | 1 | more than 2.5 times |
Methane has a much shorter atmospheric lifetime than CO2, but it is a much more potent greenhouse gas, absorbing far more energy while it exists.
That combination, powerful but short-lived, makes it fundamentally different from CO2.
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Why the difference shapes strategy
The lifetimes are the whole story. CO2 is the long-run problem: it accumulates and warms for centuries, so it is the ultimate target.
Methane’s concentration is already about two and a half times pre-industrial levels and rising.
But because it clears in roughly a decade, cutting methane cools the planet quickly, which makes it the fastest available lever to slow near-term warming. CO2 is the marathon; methane is the sprint.
ELI5
Two main gases warm the planet. Carbon dioxide is the big one: it builds up and stays for hundreds of years.
Methane is much stronger for its size but disappears in about a decade.
So carbon dioxide is the long-term problem, and cutting methane is the fastest way to cool things down quickly.
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