Glaciers speed up in summer, slow down in winter—here's why it matters

Technology Dec 07, 2025

A global study found that almost every large glacier moves faster in summer and slows down in winter.
This happens because warmer temperatures create meltwater that acts like a slippery layer under the ice, letting glaciers slide more easily.

Different regions, different rhythms—and rising seas

Not all glaciers peak at the same time.
Since 2000, melting glaciers have added about 18mm to sea levels—roughly 6,500 billion tons of lost ice.
The bigger the seasonal speed swings, the more likely a glacier is to lose ice quickly as our planet warms.
Tracking these changes helps scientists predict future sea-level rise.