There are other theories around the PETM and the details remain
uncertain. However it can be said with some confidence that the
PETM started with a warming due to CO2 emissions that was then
amplified by a low carbon13 source, methane seeming the least
problematic option. In most areas of science one can afford to
remain agnostic about issues in doubt, however Anthropogenic
Global Warming (AGW) and the risks it poses, methane hydrate
being just one, do not allow for a 'wait and see' approach. So
my working assumption is that the PETM was indeed a warming
amplified by methane, with marine hydrates being a likely
candidate for a major player in the amplification. Working on
the assumption that methane emissions were the amplifying
factor, the next issue is whether the geological record can tell
us the speed of the emissions. McInerney & Wing's 2011 Review
paper states that the onset of the negative excursion of
carbon13 took less than 10,000 years, that being the time from
the non-depleted samples to maximum de