He dedicated himself to geomorphology and climatology, and he raised the international profile of the Vienna school of physical geography.

[2] With Eduard Brückner, he coauthored Die Alpen im Eiszeitalter, a work in which the two scientists identified the four ice ages of the European Pleistocene (Gunz, Mindel, Riss, Würm); these being named after the river valleys that were the first indication of each glaciation.

During World War I he supported German expansionism, helping to develop the existing concept of Lebensraum (living space: territory necessary for a nation state, specifically for its prosperity and security).

[11] This led the American geographer Davis to write: "He used to be liked as much as admired, but during the war some of his statements have lessened the esteem formerly felt for him: into that matter we do not enter farther here".

For instance, the annexation by Germany of the Reichsgau Wartheland after the 1939 invasion of Poland was justified using Penck's concept of kulturboden (or "German soil").