[brutusborn]

It’s not really a problem, you just adjust the size of your assumed storm. We have lots of climate models and data to adjust predicted sizes.

Climate change effects are already being included when calculating wind and wave loading in many codes.

The real issue is that engineering codes use frequentist methods which make it hard to consider uncertainty, which often makes it unclear what the real safety factors are. This issue is being solved by using probabilistic engineering techniques, and in future, more sophisticated causal inference.

[s1artibartfast]

Climate. Models aren't really specific enough to predict a new 500 year storm in a specific location.

Those thresholds and definitions are based on the data record, and already encoded into regulation and a 100 years of construction.

What we see instead is Regulators simply increasing the requirements from a X year storm to a 2X year storm, and leaving the definitions. This is what I have seen with the California building code

[beerandt]

You're on the right track, but your framing is still off wrt how the engineering design process works.

Assuming that designing for a 500-yr storm has anything to do with 'predicting what a 'future 500-yr storm' (or 25-yr or 100-yr) looks like is dead wrong. Irrelevant.

The 'definitions' are not left alone, they are updated as time goes on. But with historical data, and they are not extrapolated/predicted out into the future.

Engineers (PEs) design by taking known criteria and then applying probabilities and factors. They do not predict criteria. It's a subtle but important distinction.

A 500yr event, by definition, is actually the one year probability of a 1/500 chance event.

And it's up to the designing engineer to choose and state whatever the assumptions are that go into that.

But a levee designed this year will use this years current 'storm definition' just as it uses this year's building code. Not a future one.

(Sometimes the storm/ event definitions seem stale because things like flood maps might only get updated every few decades.)

[CGamesPlay]

> It’s not really a problem, you just adjust the size of your assumed storm.

Adjusting how you call the storm doesn't make the wall bigger: that's the problem. (It also makes their statement untrue in the present day, regardless of if it was true when the wall was designed.)

[beerandt]

It's not 'adjusting how you call the storm'.

It's the engineer defining his design criteria (the 'design-storm'), based-on and benchmarked-to local historical data, including recurrent intervals.

The wall doesn't need to be bigger if next years data changes. It was designed for a (this year) 100yr- or 500yr-storm, not a guess of hypothetical future one.