There's a great read called 1215 written by Danny Danziger, exploring UK society back at the time of Magna Carta.
I can't remember precisely the number but the climate was 1.5C warmer than 2003 and red wine was being grown as far north as Ely and white wine into Scotland, crops etc far higher up hill slopes as well. In fact, the drinks of choice were wine and mead, beer only coming to the fore when we dipped into the Tudors and the Little Ice Age which changed our crop growing.....Yep, climate change has always happened and has had a number of inputs both human and physical. On the latter, Krakatoa, a medium-large volcano, threw us back into colder winters at a time when we were warming up - look at all those early Christmas cards with pictures of the Thames frozen.
On the human front, the one thing I despair is the Amazon. It's not the first time, the Romans deforested the Libya hills and looked what happened there, the Sahara encroaching through and taking over part of the Roman 'bread-basket'.......