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Comment by throwyweather | Hacker News Reader

Correctness of numerical codes is a huge and under-appreciated concern in climate models. There have been some attempts to apply software correctness techniques to climate models. For example, https://people.engr.ncsu.edu/jwb/papers/altuntas-correctness...

Much more work in this direction is needed.

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... but if you think, "hey, so the models could be wrong, how reassuring", think again. It's just as likely that reality is worse than predicted.

> It's just as likely that reality is worse than predicted.

This cannot possibly be correct; it's the same reasoning as the argument "Either the sun will rise tomorrow or it won't. These two possibilities exhaust the entire space. Therefore, the odds of the sun rising tomorrow are 50%, one in two." The premises are completely correct -- and unrelated to the conclusion.

It isn't the same reasoning at all. Our prior for what could possibly happen should be informed by what has happened before, and we know to the best of what geology can tell us, that many mass extinctions on earth were caused by CO2 mediated warming, including the one that wiped out 95% of all species at the end of the Permian. https://www.nytimes.com/2018/12/07/science/climate-change-ma...

How can you say that unless we know how to sort good models from bad ones before observations kick in? As far as I know its always very easy to fit historical data with thousands of models but very few will actually be useful for prediction and we have no idea which ones.

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