Questions, good ones

1. How long does CO2 stay in the atmosphere
It makes a big difference. If it stays 100 years, then each year 1% of the 400ppm drops out, or 4ppm. If 25 years, that's 16 ppm. 400, 1ppm.
Mona Loa data shows CO2 concentration going up and down seasonally. Surely, in natural seasonal variation, down must be greater than up, since some carbon is "sequestered" in the tree rings.

2. How much of emitted CO2 goes into the Ocean?
If it goes in the ocean, it does not go into the atmosphere.

3. How much heat goes into the Ocean?
How long does it take for the ocean to get hot enough to reject all attempts to stash heat in the ocean? I suppose when the ocean reaches atmospheric temperature. But the ocean can't change temperatures as fast as the atmosphere can. The atmosphere can drop 20 degrees in the blink of an eye, as you know.
El nino, which is a larger than usual hot patch in the pacific, blocks heat from going into the ocean. If the air can't cool down, it stays hotter. The standard problem.

4. How much energy will the world need in 2030?
How many 1G nuclear plants would we need to build each year? Many.

5. Solar radiation to land seems so different from solar radiation to ocean.
Different level of re-radiation from ocean, as ocean is cooler than land. Delayed reaction.

6. They say, here, "Without this natural greenhouse effect (but assuming the same albedo, or reflectivity, as today), the average surface temperature of the Earth would be about 60°F colder."
This means, doesn't it, that 300 ppm has a 60°F temperature effect.

7. Simplest solution is to consume less. A good discussion here: [1]