Your source is a "Reference guide for primary", it clearly states "Europe's average temperature", and grapes have been grown in Britain continually from the Rom

Your source is a "Reference guide for primary", it clearly states "Europe's average temperature", and grapes have been grown in Britain continually from the Roman occupation up until WW2. Global temperatures were not warmer in the past, because there was less energy retained due to lesser amounts of greenhouse gases in the atmosphere.