It was wetter in Roman times but the UK was also warmer, we were the bread basket of the Roman Empire. Grapes were commonly grown here too. The water table may well have been higher but we are unlikely to see it return to that level due to the phenominal amount of groundwater extraction that goes on now. don't forget all the drought orders as the aquifers are empty.
It got cooler in Medieval times then to the extreme of the Thames freezing over in Victorian times. Its quite probable that Man's use of fossil fuels warmed the climate up from then on.
We are, as far as we can tell, still in an ice age, there have been longer & warmer interglacial periods than the present 10,000 year one. Ice ages are not just about atmospheric CO2 levels, but more likely to be caused by Solar output. We've only been measuring Solar output for 50 odd years and both heat and radio output have been falling in that time. We won't know for another year and a half if the Sun is going into a Hibernation Period. If it does, then its more than likely that the ice sheets will start to roll across Europe and North America again.
This was bad enough last time but now there are Millions of People in the way. Where will they all go?
I've got my own theories as to why we are being told Global Warming is such a bad thing. You never hear a Politician start a Global Warming speach with the truth.
The truth is, CO2 levels now are at their lowest point since the Coal Measures removed loads of it from the atmosphere in the Carboniferous Period. They have been thousands of times higher in the past.
If Global Warming continues, we will loose low lying land, The Fens, Holland, Bangladesh & so on.
If the ice sheets extend as far south as they did last time we will loose half of Europe, all of Canada & a bit of North America.
Puts it into perspective really.