A collection of essays has been published by Age International and, if the roll call of interesting authors is anything to go by, it looks like the issue of ageing has finally arrived at the main hall of the global development conference centre.

As most people know, older people are the most likely to vote, whereas under-18s have no vote at all, meaning that, at the national level, old people tend to be fairly well served by democratic politics.

But the reverse appears to be true in international politics. Think of the plethora of international children’s charities – and then try to name more than one for old people. And though Unicef is a $4bn (£2.7bn) a year megalith at the heart of the UN establishment, there is no UN organisation for old people – although they do have a UN “day”, if that means anything any more.

Old people did not have a millennium development goal, and in the draft of the sustainable development goals, there are 23 references to young people and children, compared with only three to older people. In the words of one of the contributors to the essays: “Sub-Saharan Africa’s older people receive little, if any, consideration in core development agendas.”

Why the lack of concern? One reason may simply be that we naturally focus our sympathies and attention on the new generation rather than the old. There is a human instinct to give a chance to the young, innocent as they so obviously are of past errors, their parents’ or their country’s. The unfairness of their poverty is that much more obvious and inspires us to respond.

Older people are hard workers and relatively productive, and they are crucial to social cohesion and child-rearing

But probably more important, and more concrete, is that threats to progress and stability, national or international, are more often associated with the jobless and disaffected youth than with older people – we simply don’t see many older people hurling chairs into onrushing police cordons. And if they are not part of the problem, nor are they seen as part of the solution – they are past it, in our consciousness, whiling away time, while the youth are actively engaged in change.

So, with old people not eliciting the same level of sympathy, and accounting neither for the world’s problems nor their solution, self-interested strategies as well as charitable instincts seem more likely to be aligned behind supporting youth.

Age International’s impressive collection of essays invests significant effort in challenging this analysis and the myths behind it. The numbers are telling. Though we are all well aware of the youth bulge, the old bulge is not yet part of the development lexicon. But by 2050, the number of people in the world aged 60 or older will be more than twice what it is now (pdf), growing from 868 million to 2.02 billion, according to the UN.

The year 2047 will be remembered, according to UN predictions, as the first year when older people (60+) will outnumber children (under 16) (pdf). Crucially, 80% of these old people will, by that time, live in what we call developing countries.

The case is fairly clear and is made in essay after essay. The failure of the international community to recognise this major demographic shift, a consequence of increased life expectancy – itself one of the finest symbols of the progress of humankind in the past century – is distorting the development narrative and the policies that accompany it.

Far more than just making the moral case for investing in older people, the authors argue that older people are hard workers and relatively productive (even if their contributions to economic development are often informal), and that they are crucial to social cohesion and child-rearing. Investing in their health and wellbeing is not only a duty, therefore, but sound economic and social policy.

Two thoughts. First, should those focused on children’s welfare view this as a rearguard action from the grey lobby, as competition for limited budgets and political energies? A facetious question to which, obviously, the answer is no. The most important policies required to help old people to thrive and contribute are likely, mostly, to be very similar to those that young people need, eg better basic services (free at the point of use) and better infrastructure. A deeper focus on older people would not be to the exclusion of others, but would ensure that their needs are contemplated as better systems are rolled out in fast-changing developing countries, for the good of old people and the rest of society too.

Second, this issue further undermines the post-colonial us-and-them, we-help-you mentality. In one of my first blogs for the Guardian how I tried to provoke British readers by suggesting that visitors from Africa might be horrified by the way we treat our old people. You may or may not agree, but, apart from social policies in the global north being, naturally, far better funded, there is no sense in my mind that northern countries are nearer to solving the problem of how to respond to ageing societies than any other part of the world.

This is an area where all countries have much to learn, and much to offer. The issue of old people is then, perhaps ironically, a thoroughly modern one in the spectrum of global development problems.