There have been in the past periods of unexplained Abrupt Climate Shift. The only way to explain them was if there was a rapid change in the planetary thermohaline circulation. Perhaps there has always been a suspicion that earthquake induced releases of oil from sub sea oil bearing rocks in the right place could disrupt the circulation. Whether or not the jolt to the system results in a equilibrium state of a radically different state of circulation is of course conjecture, but the historical record does point to rapid temperature shifts in the time space of less than 10 years. Some have even speculated even a couple of weeks. i.e. it gets substantially hotter or colder and just remains that way for the next few thousand years. It is extremely difficult to model non linear and heterogeneous systems especially with regard to the interaction of the climate and the heat flows within the world oceans.