I) The world's climate is not and never has been constant. II) Climate, the long-term behaviour of weather, is inherently changeable. III) Not only are there gross changes over geological time scales (ice ages and interglacial warm periods) but smaller changes occur, too. IV) This was the time of the so-called -"Little Ice Age". V) Temperatures in Europe during the -medieval warm period were on average 0.50C warmer than they are now.