Is that from the book? If yes it is another bullshit part of it. True that methane will disappear over time as it is consumed by the biosphere and the extreme spike of warming will end. But that would not cause an ice age. When indstrial CO2 emission ceases the best that would happen over time is that the atmospheric CO2 level declines slowly as the oceans and plants suck it up. Pre industrial levels won't cause an Ice Age. Other external influences might but there are irreversable effects. No ice at the north pole means the ocean will absorb sun heat in the summer that an ice cap would reflect back into space. So once the north polar ice cap has gone it will not come back.Originally Posted by beazalbob69