University of Kansas professor Dr. Barney Warf received global recognition for his in-depth study “High Points: A Geographical History of Cannabis” published in 2014 by Geographical Review. Dr. Warf, who works in the Geography and Atmospheric Science department, wrote in the study that the Ice Age glaciers affected the early biogeography of cannabis. We asked the good doctor to elaborate.
“In all its forms, cannabis is a plant that likes hot temperatures, especially when it's getting ready to breed,” Dr. Warf explained. “It thrives in the summers and goes dormant in the winters. It may have grown way up into Siberia at some point, and then we know that there were a series of glacial periods, about four major ones, that covered much of northern Eurasia with these huge ice sheets. They basically changed the whole climate of that area for quite a long period of time. No plant could grow on the glaciers, but even in the areas just south of them, it was still cold and cloudy and not hospitable for a plant like cannabis. It may have moved farther south, like refugees from these glaciers, into the southern part of Mongolia and even into China. In a sense, a plant doesn't move except by growing differentially in different places. It just couldn't survive in the areas that had become so cold because of Pleistocene glaciers. We know it's distinctly an Asian plant in origin. It was humans who brought it into Europe. It didn't exist in Europe before or during the period of the glaciers there.”