🧊 The ocean freezes too

This animation shows sea ice concentration on the Spilhaus projection: the proportion of the ocean surface covered by ice at each point. It does not show thickness, but coverage, from nearly open water to areas where ice covers almost the entire surface.

🌍 Spilhaus lets us see the ocean as a single connected body of water, without any region disappearing behind the globe. Here, that perspective reveals the pulse of both poles: while one gains ice through its winter, the other loses it through its summer.

❄️ Watch the edges. That is where the seasonal change is most visible: ice advances across the ocean and then retreats, turning vast stretches of open water into an ice cover and back again. It is not a fixed boundary, but a transition zone that is constantly changing.

🧭 The two poles work differently. The Arctic is an ocean surrounded by continents; Antarctica is a continent surrounded by ocean. That geographical difference shapes where the ice can spread and how winds and currents redistribute it.

⬇️ One distinction worth keeping in mind: this is sea ice, formed when ocean water freezes. It is not icebergs calved from glaciers or ice shelves, nor the ice that covers the continents.

📊 Data: ERA5, Copernicus Climate Change Service (C3S)