[Pollster1]

The "Medieval Warm Period" (950-1250 AD), also known as the "Medieval Optimum" was one of the best times for agriculture in history. The name "Optimum" was obviously not chosen because global warming caused the worldwide disasters that big government alarmists are predicting. We are unlikely to reach those optimum temperatures in the next two centuries under realistic climate models. Polar bears and other allegedly delicate species did not go extinct in that time frame.

The "Little Ice Age" (1350-1850 AD) was a far more difficult time for agriculture. While evidence clearly shows that temperatures warmed as the earth left the Little Ice Age, the modern response to that observation should be "duh!" and not "oh noes!"

[SES1066]

Of course taking this graph into earlier times would show how a good warm climate apparently led to a population spurt in the mid-Asia Steppes that forced the Hun/Goth/Vandal migrations into Europe that pressured an aging Rome and then the 400-900 cold snap that killed agriculture and Pace Romana.