Cloud cover over land reduces global warming but not over oceans?

Why?

Think of the oceans as a giant hot water heater. Once heat goes into the oceans it stays and stays and stays.

However, over land it is a completely different story?

Why?

Because at most the heat of the sun only penetrates down 3 to 6 inches or to a foot at most. If you dig a hole in the ground and feel it before it has direct sunlight you can test this for yourself anywhere on earth. However, in loose sand in deserts this can be different because of the air that stays around the grains of sand. But, in dirt or mud the 3 inches to 1 foot is pretty normal around the world except in extreme heats and extreme colds which might be deeper than this.

Whereas heat in the oceans that is received from the suns over blue waters goes at least 30 feet deep or more depending upon factors like currents etc. that tend to mix heat even deeper into the oceans.

This is why it is perfectly feasible to have an ice age on land with waters surrounding that land which are 90 to 100 degrees Fahrenheit. The ice age would be caused by extreme evaporation from oceans causing extreme clouds and extreme precipitation. Then because of the cooling of the lands from extreme cloud cover you get conditions where the lands are cold enough not to melt the snow for long periods of time. This is what creates a short or long term ice age. Then the air is refrigerated by the ice on the ground and perpetuates the cycle sort of like a freezer unit in a refrigerator.

So, I was thinking how do you reduce the heat in waters over oceans?

But, here's the problem now.

If you reduce the heat over oceans by occluding sunlight in some way you also risk creating an ice age over lands because of the above dynamics I'm writing about here.

So, there is no one fix (likely)  that will work reducing heat in oceans and on land at the same time.

So, efforts to reduce heat in oceans likely would tend to create an ice age on lands.