Thou sayest and I agree - it's called 'practical'. Of course we need to make quantitative judgments, for all the good reasons. There is also the quite non-linear effect as x-->0 (seen clearly in the prices of ultra-pure materials, as for spectroscopy.) "Ten-nines" captures the spirit.

But the means cited of demonstrating 'risk' I deem to be philosophically trite, especially in the "things sorta like Other things must be sorta equivalent" postulate.

Always there shall be those who really do prefer to live fast, die young and have a good-looking corpse / others shall emulate the Jains (wearing bandages on feet, lest a tiny critter be snuffed.)

"Hey those steroids got me Babe Ruth's record! and ten Rolexes; so what if I look like death warmed-over, at 52? - if I make that."

Homo-sap may be capable of nice distinctions - but we are irrational in all the matters which bear upon 'longevity', and especially on every quality VS quantity 'choice', IMO. Individuation - we may kill over the concept,at the drop of an anthem - while flocking like lemmings to the mall, warz or no warz. Love. It.

Anyway, your sources make a pretty sane case for the expectation that the cost of reducing 5 ppb to 1 ppb - may make no descernible difference; clearly that extrapolation is well within the noise window; we probably Can't afford to see if there's a surprise at that low end.

(Just another reminder of the typ black/white reportage in these cases.)
It's easy to pile-on the US Military, though: 'odds' usually are, that you err on the soft side; that you will be missing the most scurrilous of actual allowed practices. Lots of simply Stupid decisions are made under the rubric "it's wartime, so.." We don't pay these epaulet-wearers to be ecologists. So far, but maybe next..

We could have really used that 1 or 2 $Trillion which this blind stumble into Revelations-geopolitics will certainly cost the descendants. There really is a point in crying over spilt Trillions, I wot. Where are the Wailers?

Shopping?


Ashton