Global Warming?

I'm going to stray into dangerous waters here.  I've always been a little sceptical about global warming - particularly when the proponents of it tried to alter the name to climate change.  It seems that the argument is based around having to pay more in fines and taxes, or be labelled a "denyer" or worse some type of heretic.  The fact remains that in my seven decades, I've not noticed a lot of change and I've never heard a serious debate on the subject.  Once again believers are only interested in shutting down any opposition.

I read an article in the British paper The Daily Telegraph on the subject the other day.  It showed this graph, which I'm sure is accurate.  A number of commentators at the bottom of the article swore the facts had been manipulated with doubtful start and stop dates.  But as with any religion, and this seems to have reached that level, advocates will never accept counter theories.  So the argument goes on.  But in the meantime could someone tell me how in Medieval times, England produced so many wine grapes that the French had to put an embargo on them.  England's climate is not warm enough to grow wine grapes without glasshouse heating, which they didn't have in those far off times.  They also had many fewer people and no evil fossil fuels.  Beats me!