If we continue to get the pension at 65, says FSC chief executive Peter Nielson, the cost of superannuation will double to 12 per cent of gross domestic product by the end of the century, requiring a 28 per cent increase in taxes.
As the Prime Minister insisted that there's no need to do anything about the qualifying age before 2020 (by which time he'll be well out of politics), Council of Trade Unions secretary Peter Conway warned that those advocating change were conveniently ignoring the damaging consequences of pushing out the age at a time of discrimination against older people in the workforce.
But if the claims emanating from the twilight zone where science meets science fiction are to be believed, the FSC's life-span projections fall way short of the mark.
Cambridge University gerontologist Dr Aubrey De Grey, a guru to those obsessed with thwarting the ageing process, believes there are people alive today who will live for 1000 years.
Ageing isn't irreversible, he says, because it's an accumulation of damage that we'll soon be able to repair. Think of a Volkswagen Beetle that's been regularly serviced.
De Grey is cautious to a fault compared with US scientist Ray Kurzweil, who reckons immortality is less than 20 years away courtesy of nanotechnology.
He claims nanobots - whatever they are - will replace blood cells, enabling us to scuba dive for hours without oxygen, run at Olympic 100m final pace for 15 minutes without drawing breath and write a book in a few minutes.
Of course such developments would render life as we know it meaningless, with incalculable results, so let's assume De Grey and Kurzweil are to gerontology what Ken Ring is to seismology and focus on what seems indisputable - in future there will be more old people, and they'll be old for longer.
Writer Martin Amis got into hot water for suggesting that the solution to the coming "silver tsunami of demented very old people" was euthanasia booths on street corners where oldies could "terminate their lives with a martini and a medal".
That was a satiric prelude to a serious point about how geriatric science can prolong existence for its own sake, without regard to quality of life: "We need to recognise that certain lives fall into the negative where pain hugely dwarfs those remaining pleasures you might be left with."
Amis had watched two people dear to him succumb to dementia, and anyone who has observed that terrible process will know what he's talking about.
Despite that and the fact that he's a grandfather himself, what he's expressing is still the viewpoint of someone not yet old.
How often have we heard middle-aged people declare that if they ever lose it, they want someone to put a bullet in them, or words to that effect?
But people who've lost it don't know they've lost it, while old people who haven't lost it and remain connected to their families have reasons to soldier on, even when physical decline has narrowed their existence to a point they would have regarded as intolerable when they were hale and hearty.
So while we worry about the economic implications of the silver tsunami, if the Rolling Stones play Dunedin next year we'll witness a uniquely 21st century phenomenon: pensioners shaking their artificial hips to the beat of a geriatric rock 'n' roll band. And we should begin steeling ourselves for the horrible prospect of a 70-year-old Madonna flashing her sagging body parts at audiences in a desperate attempt to prolong the dying of the light.
