Are 'Return Periods' being recalculated? If so, how?

The concept of 'return period' (= 'average recurrence interval', or ARI) is widely used in hydrology, and to a much lesser extent in geology, geomorphology, geophysics, etc. Whatever the application, the traditional analysis is predicated upon 'stationarity of the data-set'. However, in this new era of climate change the hydrologic data set is, by definition, no longer 'stationary'. That is, the underlying statistical parameters are no longer consistent. Therefore, a new methodology is required to take account of the drift in climatic means, extremes, revised frequencies, etc. Are there any first attempts to deal with this problem?

• You'd probably have to look at different literature for each type of event. Stationarity is fairly hard to show even with stationary datasets, and any calculation of a return period of an event is going to be highly dependent on the dataset(s) used for the analysis. – naught101 Nov 3 '15 at 2:09
• I'm not sure if return period and average recurrence interval are truly equatable. As far as I understand return period relates to the chance an event has of occurring in any given year, which is subtly different. As for whether such concepts are stationary, you'd have to look into the scientific consensus as to how much regional and global climates have changed since such concepts were formalised. Personally at present I think with regards to insurance industry use of the terms, any climate change value change will be massively dwarfed by the increased value of property which is now insured. – Siv Nov 4 '15 at 20:47
• – Siv Nov 4 '15 at 20:58
• This is a big controversial topic in hurricane season prediction. Sometimes, when environmental conditions are in flux, there is simply no answer. IOW, statistical return period can not be calculated to better than a factor of a few. Almost all climate predictions, based on records of occurance, are up in the air. We no longer have a good statistical handle on El Niño versus La Niña, basic predictions for the coming season, the jet stream, even monsoons in some locations. There is no consensus on how to deal with this. Models now carry more weight than past statistics. – Eubie Drew Nov 5 '15 at 1:42
• @Aabaakawad I suspect that the last sentence of your comment may be the core of a good answer. If you'd care to expand, I'd certainly upvote it :) – Semidiurnal Simon Jan 10 '16 at 12:39