Heat waves are on everyone’s mind, and while we lack the expertise to accurately predict the impact of climate change on agricultural production, history offers some interesting observations. The Medieval Warm Period between 750 and 1350 AD involved an unusual temperature rise that melted glaciers and led to a revolution in European agriculture. There was also less moisture. Crop yields tripled and the farms of Northern Europe outperformed their Mediterranean counterparts. Three-field crop rotation along with other agricultural technologies developed.  Winter grains previously turned into whisky or beer were replaced with grapes and increased wine making. However, warming in the modern era has a different market situation. Globa...