Well, we know from UK geology that the climate during the Jurassic, in central England, was akin to the modern climate of Florida and the Caribbean. Why?
Some geologists think this is actual evidence of a higher level of co2 in the atmosphere back then – what else could cause the climate to warm? What, indeed.
At http://phys.org/print299258421.html … we read how scientists have theorised there was no polar ice sheet in the Cretaceous because the climate was much warmer. Obviously, this has more to do with CAGW and the necessity to keep the meme going that all the ice in the Arctic is going to melt (even though it has increased considerably this year). Should something like this be part of a geological paper?
The claim is it was 1000ppm – a lot more than the current 400ppm, co2 levels that we have all been told will be absolutely disastrous, not just for humans but for the wider world at large, which includes all that inconvenient ice up north. They also used the fossil shells of foraminifera plankton to measure the ratios of oxygen isotopes, in the sea off the coast of East Africa. Here they found no evidence of cold water oxygen isotopes – but is that all that surprising, as after all it is not too far from the equator and in the Cretaceous may have been somewhat closer still. No evidence of the kind of cool water that would be expected if there was ice at the poles – does have a certain ring to it. Foraminifera are regularly used to check out oxygen isotopes, especially in the Atlantic. They are tools that are used in the Ice Age debate – said to be firm evidence of the existence of the Ice Ages. Hence, there is a long history of using these tiny shells.
The same story from the same paper in the journal Geology pops up at Anthony's place – go to http://wattsupwiththat.com/2013/09/26/study-the-late-cretaceous-period-w… … and begins by saying that for years scientists and geologists thought there was ice at the poles during the Dinosaur Age. Now, a new group of researchers are telling everyone this isn't true – but how much of the CAGW meme was part of the press release associated with the paper and how much is it part of the paper itself. Many such papers pay lip service to global warming as it pays the bills – and encourages the next grant. Some of the comments are worth reading – if you have the time and inclination.