Planning for worst-case scenarios depends on a lot of 'ifs'.
In a climate-change context, that means if temperature rise is as fast as feared, if actions are insufficient to halt it, if the consequences are as drastic as predicted, and if we can't protect ourselves from those outcomes.
If - two little letters which lie between comfort and chaos. It's such a small word with such huge implications that it is tempting to push it aside and adopt the far more appealing 'it might never happen' attitude.
But if it does happen, the modelling carried out by Gamma Location Intelligence is worth attention.
Flood modelling has been carried out before and this one doesn't stray too much from previous exercises, but what makes it different is that it counts the number of homes and commercial premises likely to be affected.
More than 70,000 addresses fall within the risk zone, the vast majority residential and many enjoying natural amenities that landlocked, locked-down households have envied these past two months.
But there may be a high price to be paid for the privilege of proximity to the sea in future - and not just at the purchase stage.
We have become used to seeing householders along the Shannon frantically pumping day and night to keep flood waters at bay when the now near-annual deluges hit them.
The sight of a weary family tearfully surveying the ruins of their belongings in the wake of a flood which couldn't be kept back never fails to pull on the heart strings.
This latest modelling doesn't even include them, but tells us that whatever the hardship suffered by riverside dwellers, it is likely to hit their coastal counterparts too - only worse and in far greater numbers.
Yet despite all we know of floods and all the warnings we get, most of the home-building and commercial development in Ireland is still taking place in our main cities, all of them coastal.
For example, 3,500 new homes are planned for the former Irish Glass Bottle site in Dublin, which has a super location beside the sea.
Under the Gamma modelling, a good part of that site would withstand an extreme storm surge but not all of it. The new neighbourhood would become a temporary island, with waters rising rather alarmingly all around it.
Maybe that's OK. With some clever design and build techniques, future housing could be built to withstand at least ground-floor flooding.
With some similar psychological adaptation, we might even become as cool with the idea of regular flooding as the hurricane-hardy Floridians who routinely ignore evacuation warnings.
Or maybe it's time to revisit those long-promised plans to rebalance development to our regional and provincial towns.
Maybe none of this will be necessary but, if it was your home at stake, wouldn't you like to think it was being considered?