Methane is produced by anaerobic digestion, which I would think is much more likely to happen when a whole area is flooded at once. The same biomass bring broke

Methane is produced by anaerobic digestion, which I would think is much more likely to happen when a whole area is flooded at once. The same biomass bring broken down in atmospheric oxygen would have a significantly lower effect. Agree the mix of ongoing and one-off effects is confusing.