The world’s coldest countries, Antarctica, Russia, Canada, Greenland, Mongolia, and others, still endure sub-zero temperatures year-round. But scientists warn that their climate is no longer steady.

Polar regions are warming nearly four times faster than the global average. Melting snow and ice reduce Earth’s reflectivity, meaning darker land and ocean absorb more heat, speeding up warming. This shift is disrupting long-established patterns of freezing and thawing.

The jet stream, which normally keeps Arctic air locked north, is weakening as sea ice retreats. As a result, icy winds can dip further south while warm air pushes north, causing extreme swings, record blizzards one season and delayed winters the next.

For communities, wildlife, and ecosystems that rely on stable cold, this unpredictability is more disruptive than the warming itself. Winters are still bitter, but less reliable, reshaping daily life in the world’s coldest places.