SCOTLAND is growing older.

For the first time, there are more people aged 65-plus than there are under-15s. This nugget from the 2011 census is the first tremor in the "agequake" about which demographers have been warning since well before the previous census in 2001. The prospect of millions of us spending at least a third of our lives in retirement has caused successive fits of collywobbles in social policy units, so the scenario is usually painted in apocalyptic language of the pensions bomb ticking.

And that harbinger of doom is upping the tempo. The number of older working-age adults (those between 40 and 64) has increased by 32% over the last 30 years, indicating a rapid rise in the number of pensioners over the next couple of decades.

But how big a problem is this? The equation of how much older people receive against how much they contribute is not simple. Payment of the state pension of £107.45 a week is more than offset by the value of unpaid care for elderly relatives that might otherwise fall to the public purse. Those who look after grandchildren make a vital contribution to family wellbeing. In economic terms, this makes them worth a bus pass and a winter fuel allowance. Pensioners, however, no more fit into one income category that any other age group: in many ways they provide the best illustration of the growing gulf between the haves and the have-nots. Today's pensioners and those about to join them, particularly from the public sector, will be the last who can count on retiring on a fixed proportion of their final salary.

That gives many of them a greater disposable income than younger people with hefty mortgage payments who are bringing up children, or those in their 20s and early 30s on low salaries or with student loan repayments. It was only the retired who spent more money eating out in restaurants in 2010 than in 2000, according to a recent study for the Intergenerational Foundation. In some cases, they might be accused of flaunting their wealth and new-found freedom. While younger age groups are economising on leisure activities, the over-50s are spending more on travel, restaurants and tickets for the theatre and cinema. Against such intergenerational inequality, the proposal from LibDem leader Nick Clegg that wealthy pensioners should lose the £200 winter fuel allowance, free bus travel and television licences for the over-75s appears a logical move in the pursuit of fairness, but raises far bigger questions of who is wealthy and whether means-testing would merely substitute one form of unfairness for another.

David Cameron's commitment to protecting all pensioners' benefits for the duration of this parliament is the result of the political clout older people now have. One calculation makes four pensioners worth seven young adults in terms of votes. This explains why the Coalition Government's knickers are in an almighty twist over age-related benefits. Clegg deserves credit for trying to disentangle the dirty washing in public, but has not begun to tackle the much bigger problems of decent care for elderly people or the shamefully large number of pensioners still living on inadequate incomes. In Scotland, how long we can afford free care for the elderly is the question politicians must stop dodging. Our lengthening lifespans mean we must re-appraise the social contract. The prospect of living in an increasingly elderly community is dispiriting only if being old means being cold and lonely. Benefits should be determined by need, not age. Bus passes are an example of one size fitting too few when cheaper fares would most benefit the oldest and youngest.

If old age brings physical slowing down, the wisdom gained from experience has traditionally been recognised as a reasonable trade-off. An older society ought to be a wiser one and a wise society would surely invest in its young, not only because we will all depend on younger people to care for us in old age but because a society with a good proportion of young people will be interesting, lively and full of new ideas. The good news is that as well as an increase in centenarians, there is a rise in the number of children under five. Long may they live.