I'm posting it again, and recommend studying the reference and some of the connecting links. What's very interesting is that they've tracked massive prehistoric climate changes in very short times (less than 100 years.) This is a two-edged sword in the climate discussion. It might mean that the presence of a drastic change does not automatically rule out natural causes. However, it also means that apparently it doesn't take a lot to flip the relay of climate change.

A post-Ice Age cold spell has been tracked fairly closely to a glacial melt incident that shoved a lot of fresh water into the Atlantic Ocean over a short time, and screwed up the current flow.

Another lesson learned is that climate change is not going to be uniform. "Global Warming" is a misleading term. Some places could get a lot colder.

That there is a correlation between temperature, CO2, and methane over history is unmistakable. But again, are we dealing with causes, effects, or some mutual feedback?