The Worlds Oceans Boiling

As you go higher into the atmosphere (and further from the Earth’s core), it gets much colder. As most of the oceans floor are closer to the core (about 10 km thick) yet as you get closer to the core it also gets much colder. Why are the oceans temperatures not warmer?

I tend to envision a large pot of water being heated on both ends by the sun and the core, churned by the current.

90 % of the total volume of ocean is found below the thermocline in the deep ocean. Much of this deep ocean water is between 0-3 degrees Celsius (32-37.5 degrees Fahrenheit)! It’s really, really cold down there!

Why is this?

Because cold water is denser. It wants to go to there.

So is it hot near the bottom?

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This seems like a lot of heat for the ocean to absorb. Does this heat disturb ocean currents?

For one thing, the deeper you go in the ocean, the less light and heat from the sun get through. But on land, where there’s nothing obstructing the sun light and heat, it does get warmer the farther down you go. There’s a noticeable difference between the rim of the Grand Canyon and the bottom.

Nitpick: As this chart shows, this is only true up to a point.

No, because heat is what drives ocean currents, whether directly (warm water rising and evaporation, which also affects salinity) or indirectly (wind, which is driven by convection and imbalances in the atmosphere).

Also, the water at the seafloor stays cold because any heating, such as from an underwater volcanic eruption, would warm the water and cause it to rise, while cold water, in the polar regions, is sinking (here is a good article on why the ocean bottom is cold).

Not only that, the thermosphere gets MUCH hotter than what that chart shows, at higher altitudes:

Also, note the last sentence, which is one reason why it can be so hot yet not make the surface of the earth hot; similarly, the Sun’s corona can be millions of degrees, far hotter (much more so than with Earth) than the surface, but is also about a trillion times less dense.

Because rock is a very good insulator. Visit Yellowstone National Park sometime. The magma reservoir is possibly as close as four miles from the surface.