For the Climate Classroom Wall: ocean heat content observed and predicted

Note the predicted trend (straight red line) compared with some actual observations. 

Quote 'If the model mean continues to diverge from the observations, how many years are required until the models can be said to have failed?'

This is a good statistical question, but it also serves an honest rhetorical purpose as a comment on this chart.

 (Source: Bob Tisdale              Hat-tip: C3)

Compare it with this material aimed at 'kids' on the NASA site:

'The ocean does an excellent job of absorbing excess heat from the atmosphere. The top few meters of the ocean stores as much heat as Earth's entire atmosphere. So, as the planet warms, it's the ocean that gets most of the extra energy.

But if the ocean gets too warm, then the plants and animals that live in it must adapt--or die.
Algae and plankton are at the bottom of the food chain. Plankton includes many different kinds of tiny animals, plants, or bacteria that just float and drift in the ocean. Other tiny animals such as krill (sort of like little shrimp) eat the plankton. Fish and even whales and seals feed on the krill. In some parts of the ocean, krill populations have dropped by over 80 percent. Why? Krill like to breed in really cold water near sea ice. What would happen if there were no sea ice? What would happen if there were very little plankton or krill? The whole food web could come unraveled.'

Quote 'The whole food web could come unraveled.' 

Do you think by any chance they want to scare the 'kids'?
Q. How can they justify this?
A. Because the model projections look alarming

Might be enough to persuade you to read Bob Tisdale's article linked to above.
Or research into what kind of of temperature rise would mean 'the ocean gets too warm'.