Lessee now---do those "models" account for all the methane it has recently been discovered that plants emit, or the additional CO2 vented into the ocean and atmosphere by the new chain of subsea volcanos just discovered under the arctic ocean?? Do those models factor in WATER VAPOR and CLOUDS??
1. For that, I'm certainly not authoritative. Try this out: Scientists baffled! (though not as much as you might think) Also, make sure to read the clarification.
Note that atmospheric CO2 still dominates the radiative balance calculations.
2. CO2 from volcanic sources is insignificant compared to fossil fuel burning, and so it doesn't affect the ocean-atmosphere exchange rate. CO2 emitted from submarine volcanoes would get converted to bicarbonate and carbonate ion before getting close to the surface anyway. (CO2 dissolves in ocean water into carbonic acid, which has a low equilibrium solubility and breaks down to bicarbonate and carbonate ion in ratios that are dependent on pH. My chemistry degree was useful for something!)
3. The largest uncertainties in the model are related to cloud feedback effects. This doesn't mean that the models don't include them, it means that the certainty on how clouds will respond to warming is less than the certainty on how other factors in the models work. Clouds reflect solar radiation back up but also reflect outgoing longwave back down, and this is dependent on the cloud type. The uncertainty is two-part: one, whether cloud cover will ultimately decrease or increase in a warmer world, and two, where the cloud cover changes will take place. Regarding the former, the house money is on an increase in cloud cover.