Temporary carbon dioxide removals to offset methane emissions

Unlike CO₂, methane emissions have a particularly large short-term effect on temperature. We argue that these largely temporary temperature effects of methane emissions are apt to be offset by temporary CO₂ removal. Temporally matching offsetting temperature reductions to the temperature impulse of methane eliminates the sizable intertemporal welfare transfers that occur when methane is offset by equivalent permanent CO₂ removals. Assessing equivalence based on avoided economic damages suggests that about 87 temporary CO₂ removals over a period of 30 years are needed to offset 1 t of methane. Agreement on the appropriate quantity of temporary CO₂ offsets is insensitive to controversial parameters such as the social discount rate, climate damages and future emission scenarios. Short-term monitoring periods of 20-30 years are likely to be more credibly enforceable for various nature-based CO₂ removal projects than long-term monitoring requirements.