Eli5: If the ocean moderates temperatures and prevents extreme cold or extreme heat, why is the arctic ocean so cold?


I just find it strange haha

In: 2

The ocean as a whole serves as a heat battery. It can warm up or cool down and this absorbs much more heat energy than the same change would in just the atmosphere.

Some of it may heat up or cool down before another part of it. The arctic ocean is around arctic air, both of which are cold. If the air above that water warms up, the water must also warm up and evaporate and help slow the change.

The ocean has a huge capacity to store heat, and releases it at a relatively steady rate. This does a lot to even out temperatures between night and day, and summer and winter. The ocean also has currents, [which go from hot places to cold places and vice versa](https://www.smithsonianmag.com/smart-news/ocean-current-keeps-europe-warm-weakening-180968784/), which evens out temperatures geographically. Like the article says, Western Europe is as warm as it is due to a warm current bringing heat from South America.

Anyway, [the Arctic ocean is mostly surrounded by land, and only gets one warm input current, the same one that went by western Europe](https://www.whoi.edu/know-your-ocean/ocean-topics/how-the-ocean-works/ocean-circulation/arctic-ocean-circulation/). And being at the pole and covered by ice and snow, there isn’t a lot of sunlight to warm up the water either.

The poles get a lot less sunlight than the equator does. So they will be colder than the regions where the sun is overhead. During the norther hemisphere winter, the north pole gets no sunshine at all. So it cools down to below freezing and the seawater forms an ice layer. Which isn’t all that thick, submarines can surface through it.

The Arctic ocean is much, MUCH warmer than the surrounding land, particularly in winter.

Russia, the far northern reaches of Alaska and Canada, and Greenland are all extremely cold places. The *average* January low in [Deadhorse, Alaska](https://en.wikipedia.org/wiki/Deadhorse,_Alaska), on the coast of the Arctic Ocean, is -42 F (or C, doesn’t really matter at that temperature). Even the average high is well below zero F. The ocean, meanwhile, sits at around -2 C, the freezing point of seawater.