Why does the transformation from firn to glacier ice take much longer in Antarctica than in warmer regions?

The transformation of firn into glacier ice is a process of densification that depends heavily on temperature and wetness. In warmer, wetter environments, such as in Washington state, this transition can occur in just three to four years at shallow depths.12

In contrast, the process takes significantly longer in Antarctica—often thousands of years—because the extremely cold temperatures inhibit the mechanisms that drive densification. The transformation relies on processes like evaporation, condensation, and the presence of liquid water, which allow ice grains to round, sinter, and pack together more efficiently. These processes proceed much more rapidly at temperatures near the melting point.1

In the frigid, dry conditions of the Antarctic plateau, these effective densification processes are slowed, requiring the weight of significantly more accumulated snow to compress the material. Consequently, the transition to glacier ice in Antarctica typically occurs only after burial to depths of approximately 150 meters.1