During the warm 1920s through the 1950s, almost all European glaciers were retreating. During the cold 1970s most glaciers were advancing.
Alps-glaciers – Retreat of glaciers since 1850 – Wikipedia
According to NASA, glaciers retreat when temperatures are cold, and they advance when temperatures are warm.
Unlike the NASA graph, the 1974 NCAR graph was consistent with the behavior of ice.
