Methane (CH₄) — τ ≈ 11.8 yr, decays fast CO₂ — long tail, ~20% still airborne after centuries Horizon marker (drag on chart)
Shaded regions = cumulative warming ("area under the curve") from year 0 to the horizon marker for each gas — their ratio is the Global Warming Potential at that horizon. Drag the yellow line, or use the horizon slider, to see why GWP isn't one fixed number.
Area CH₄ (0→H)
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Area CO₂ (0→H)
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GWP-20 (fixed ref)
≈ 80×
GWP-100 (fixed ref)
≈ 28×