But isn't it usually the case that forecasts are normally proven wrong, mostly because some unrealized third factor was not considered (or known) at the time the prediction was made? Seems like every day there's a heretofore unforeseen factor that has accelerated metric X beyond initial forecasts, and these forecasts need to be recalculated to account for X, as well. (Ice cap melting speed, foliage regrowth after disasters like Mt St Helens or Chernobyl, etc...) Or is this just my impression, and not reality...? For the record, I am not at all expert in sea level change. I’m entering the bet on the basis that your forecast appears to exceed most official projections, which if anything have a tendency to exaggerate the threat IMO.
In this case, one forecast will be right and one will be wrong, depending on whether the final value is above or below 402. Some unanticipated factor could influence the result, or a known factor could have unexpected effects. There is always uncertainty in predictions; if everything were known in advance there would be no value in making forecasts.