I once interviewed a brilliant 101-year-old Edinburgh woman called Phyllis Ramsay who told me that one of the reasons for her longevity was her daily diet (porridge for breakfast, sandwich for lunch, something nice from M&S for dinner). She’d also never smoked and had been drunk only once in her life, when her son passed his accountancy exams.

I mention Mrs Ramsay because I’ve been thinking about the year 2072 which is when I (with a bit of luck) will be 101 years old myself. Mrs Ramsay’s assessment of the world she was living in as a centenarian was mixed it has to be said: the British, she believed, were too obsessed with the past, which was why Brexit happened. She also worried that, because of technology, people weren’t as happy as they used to be. And like all wise old people, she was shocked by the state of the youngsters’ grammar.

But what, I wonder, will it be like for me, and others of my generation, when we hopefully reach 101 years old too? To some extent, Mrs Ramsay obviously benefited from the post-war, baby-boom economy and I suppose I was at the fag-end of it too. When I went to university in the 80s, I got a bit of grant. And in the 90s I was able to buy a flat in Shawlands (for £44,000!) with a 100% mortgage. Happy days.

By contrast, the situation for young people in 2072, when I will, God willing, be enjoying a relaxed retirement at 101, will not be so good, according to the latest predictions. The Scottish Fiscal Commission says that by 2072 there will be 900,000 fewer Scots than there are now, the equivalent of a 16% fall. It also said that only 56% of people will be aged between 16 and 64 in 2072 compared to 64% in 2022.

And they’re not the only ones making these kind of predictions. According to the National Records of Scotland, by 2045 the number of pensioners in Scotland will have increased by 22%, while the number of workers will have fallen by two per cent. Esther Roughsedge, their head of population and migration statistics, said: “If past trends continue, we project that by 2045, Scotland will have a smaller and older population.”

The potential consequences of all of this are pretty obvious I would have thought. More demand for health and social care from the likes of me at the age of 101. Fewer working-age people paying tax. Result: the shrinking number of young people will have to pay taxes for longer to care for the large number of old people. From the future, I say sorry to you all.

Lots of countries, of course, face these kind of pressures, but the Scottish Fiscal Commission says the problem will be particularly acute in Scotland – in fact, we might call the projected difference between the young and old the “Scottish Gap”. One of the reasons for it is the low and dropping number of births, a trend I certainly see in my contemporaries, who’ve had many fewer children than our parents did. A decrease in net migration is also blamed.

But if we accept the premise here – the projected Gap – an important question is the political consequences of it, because there’s a chance, isn't there, that in 2072, at the age of 101, I will be voting in indyref9. On the face of it, the dilemma we’d face is clear: a country with lots of old people and not enough young people would surely mean bigger bills and less money coming into Holyrood so what’s the best political way of dealing with it?

I guess nationalists would say an independent Scotland with vastly boosted migration would be the solution, but that’s easier said than done. It’s interesting that as well as predicting an overall drop in the population, National Records Scotland also noted a recent rise in the population in rural parts of the country. Sadly, I fear this is mainly down to middle-class townies looking for a sort of perfection they’ll never find rather than lots of people flooding into rural Scotland from abroad. Truth is: living in large parts of the Scottish countryside is difficult and expensive which is why non-UK migration there is low.

We also need to be cautious about saying the Scottish Gap would necessarily mean less money for Holyrood because of the peculiarities of the UK set-up. The Institute of Fiscal Studies said this week that a decline in population would actually mean a benefit to Holyrood because of the way the Barnett formula works to protect Scottish budgets from population-driven shortfalls. The IFS analysis suggested slower population growth would in fact mean 8.5% more funding per person by the 2070s. Woo-hoo: all the more to spend on the centenarian that I will be then.

Of course, you’ll have noticed that this uplift depends on us still being in the UK. The idea of a shrinking and ageing Scottish population actually being better off also depends on us accepting, first, that the population projections will come true and, second, that the Barnett formula conventions would remain in place. There’s no reason to suggest they wouldn’t I guess, although it might surely also become increasingly awkward politically if much more money was being spent on many fewer Scots.

All of these factors are difficult to predict, but it does raise the interesting prospect of Scotland being effectively “trapped” in the UK by its demographic trends. Assuming mass migration couldn’t fix the problem – and I don’t think it could – we’d have a shrinking nation that needs to stay in a union with a much bigger nation that isn’t shrinking by nearly so much. And I think I’m okay with that. Sounds like a pretty good deal to me.

I’d also like to think that the wisdom of a century would lead us to the same conclusion. The brilliant Mrs Ramsay told me that she was opposed to Brexit because of her sense of internationalism and she was opposed to Scottish independence for the same reason. She was also, as I said, deeply suspicious of looking back on old glories or forward to mythical future ones. I do not know, obviously, what 2072 will really be like, or whether I will be there. But I’d like to think that Mrs Ramsay’s common sense would still apply. I agree with her, now and for the future.

Our columns are a platform for writers to express their opinions. They do not necessarily represent the views of The Herald.