G'day Paul,
The reference to God was to make a point. It was certainly not an attempt to name call at all. That is something I do not agree with on any forum for discussion. I do hope you appreciate there is a big difference between exaggerating to emphasise a point such as the reference to God and actually calling someone a God or believing they think they are.
As best as I could find, there is no evidence for any significant release of methane 11,000 years ago. It is not an area in which I have any particular expertise at all, as it has never been brought up in the area where my fascination lies. Having looked at the information available, methane has the potential to make major climate changes if released in large quantities. It may well have done so, as I previously said 55 million years ago (or the methane might have been released in response to a massive climate change - I do like these chicken and egg questions especially when there seems to be no science to support either argument well).
As to "rivers" on the ocean beds, dehammer is right in respect to massive rises and falls in ocean levels. In this Ice Age (somewhat more than a million years in geologic time), there has been a great many fluctuations in sea levels. They have been around 120 metres lower than they are now and around 40 metres higher. There is less evidence, but still some evidence, to suggest that lower levels have occurred.
Now 160 metres is a very long way indeed. It means the difference between much of the continental shelves being exposed and well underwater. To use a nice simple example, Sydney Harbour, is quite famous for its natural beauty (and the yearly fireworks that are amongst the first in the world - it starts at Tonga, then NZ, then eastern Australia). It is a river bed as are a great many other major world harbours. 20,000 odd thousand years ago, there was a creek running where ferries now travel. The creek could be waded across in drought times. The water edge for the coast was as much as 8 kilometres (about 5 miles) further out that it is now, thus what is seen on most continental shelves are the remnants of rivers, creeks, etc that flowed during the last lower period.
The theory that makes sense to you would be a good theory if any evidence supported it and that is what these forums are for. To discuss the evidence available. The references you provided did not actually suggest that there was a major release of methane 11,000 years ago or that this was the cause of this interglacial period.
As to the far distant past, the evidence is that the world was a pretty hot place indeed. At different periods the world was much hotter than today but generally, and this is a very big generalisation, the earth has cooled over the millennia.
What is not a generalisation is just how recent human habitation has been. Humans did not get swept back down to sea by rising sea levels in the times that climates changed greatly because humans just were not around during almost all of those changes. Human life is pretty much confined to this Ice Age. Before that and our ancestors were more ape like than human like. It was only about 700,000 that the acceleration towards human like creatures began, with the use of fire becoming widespread and therefore, the need to digest raw food being reduced meant that other developments could occur.
Humans have suffered greatly due to the flip flops between interglacial periods and glaciations in this ice age and my guess is that floods caused some losses but most of the losses were the change to environment that made life harsher.
Pretty much all modern human development has been in this one very very small interglacial period. Before that settlements were not permanent. Think of the way of life of the Inuit, American Indians, Australian aborigines, New Guinea tribesman, for an idea of how life was for most humans before the dawn of this interglacial period and the settlement near the Mediterranean that ended up in "civilisation".
You also mentioned deep ocean floor patterns as part of a theory on methane release. This is also not an area of expertise but I understand that there are some really fascinating reasons for the patterns but they were not made because the water is normally warm and into it intruded "rivers" of cold water.
Very cold water is part of the ocean depths. It is near to freezing anyway. Whether the world above the sea is warm or cold makes pretty much no difference to the temperature of the water at significant depths (I say pretty much because the very small differences caused by very slow vertical currents actually do have a significant effect on climate but in terms of what would normally be considered "warm" and "cool", the difference is negligible). So icy waters flowing from above the oceans just wouldn't do it. The icy water entering from the Antarctic for instance, is pretty much the same temperature as the water it eventually reaches at depth, close to zero C.
Paul, you have an interesting perspective on the world and obviously are interested in this topic. It is with evidence that even seemingly outlandish theories have been proved correct or had to be discarded. Plate tectonics is perhaps the classic example in Earth Sciences of a theory that was really taken as a crackpot theory until eventually the evidence was presented that was too overwhelming to ignore anymore (amazingly that took around 60 years after the evidence was available but that is one of the really big drawbacks of theoretical science, peer review and the inertial in scientific thought where it does not conform to the mainstream).
As to methane causing climate change whether in the short term or in the much longer time frame, there does, in the end, need to be evidence to suggest that this is a valid explanation. Certainly in the short term, there does not seem to be any such evidence at all.
Richard
