Glenn Thomas Trewartha

Glenn Thomas Trewartha (1896 – 1984) was an American geographer and climatologist of Cornish American descent. He is best known for his eponymous Trewartha climate classification, an expanded and modified version of the Köppen–Geiger system.

He graduated from the University of Wisconsin–Madison, with a Ph.D. in 1924. He taught at the University of Wisconsin.

He gave an address to the Association of American Geographers, "A Case for Population Geography", in which he argued that "fundamentally geography is anthropocentric, and if such is the case, that numbers, densities and qualities of the population provide the essential background for all geography. Population provide the essential background for all geography. Population is the point of reference from which all other elements are observed, and from which they all singly and collectively derive significance and meaning". He also wrote about climate, explaining that the atmosphere was like "a pane of glass in a greenhouse... thus maintaining surface temperatures considerably higher than they otherwise would be."

Awards 1926 Guggenheim Fellowship

Works "The earliest map of Galena, Illinois" Wisconsin Magazine Of History. Volume: 23 /Issue: 1 (1939–1940) A Reconnaissance geography of Japan, University of Wisconsin, 1934 Elements of geography physical and cultural, Glenn Thomas Trewartha, Vernor Clifford Finch, Mc Graw-Hill, 1942 Japan, a physical, cultural and regional geography, University of Wisconsin press, 1945 An introduction to climate, McGraw-Hill, 1954 Japan, a geography, Milwaukee: University of Wisconsin press, 1965 An introduction to climate McGraw-Hill, 1968 The More developed realm: a geography of its population, Editor Glenn Thomas Trewartha, Pergamon Press, 1978, The Earth's problem climates, University of Wisconsin Press, 1981,