On the day of the pre-budget report my teenage son was listening to a news item about the huge expansion of government borrowing, and the debt being built up for the future. "I don't understand - who's going to pay for all this?" he asked. I thought for a millisecond. "You are," I said.

The fallout from the financial crisis is just the latest burden we are about to place on the shoulders of the younger generation. For the past 50 years or so, our society's been having a party. It's true that not everyone was invited, but those who were had a very good time. There is, for instance, the golden generation. That's the term for the people lucky enough to retire, often early and with final-salary pensions, around the start of the decade. They had free university educations and hit a rapidly expanding market for middle-class jobs. They walked into employment, rode the property booms as inflation made nonsense of their mortgages, and could even fly to Asia or Antarctica without knowing they ought to feel environmental guilt.

The people 10 or 20 years younger than them didn't do badly either; spending and consuming in abandon while watching the value of their assets grow. But now the bills are coming in, and people who are young now will face a much tougher future.

Take education. Students already expect to pay for university, but they do so because they have been assured that it will be an investment. A shrinking economy threatens that. In a tough job market, those who get offers come from the most prestigious universities and most taxing courses. The thousands of people who have been urged into new universities and narrow courses are already finding it harder to get jobs, and it will get worse. The general graduate premium is dwindling fast - Swansea University recently estimated the lifetime value of the average degree at no more than £22,000.

Bob Worcester, of the polling firm Mori, thinks the overhang from the hole in public finances could affect young people's lives for decades. "I'm very conscious that students are leaving college owing between £12,000 and £20,000, and while the debts are there, the jobs aren't. Especially for the soft-touch degrees, the ones that don't teach wider skills."

The economist Bridget Rosewell is equally worried by the pressure on young people to go into training rather than work. She has sat on quangos whose purpose is to get people into colleges and improve their skills so that Britain can compete internationally. "We've created a system that's better at producing courses than skills that are useful to the individual or society."

Even falling house prices aren't automatically good news for the young. Homes are still expensive compared with salaries; loans without high deposits are impossible to find; and those who buy at a time of very low inflation are going to find their mortgages won't shrink as they did in the past. The only people exempt from this will be those whose parents can spare some capital. In other words, generational inequality is going to further entrench social inequality.

While college leavers delay their entry to the job market and accumulate debt, they are shortening the period in which they are available for productive work. That's serious, because in their lifetimes they are going to be expected to build up their own pensions and save for them in a way that previous generations were not obliged to. Simultaneously they are going to have to pay, either through taxes or by producing profits, for the lifestyles of all the people who have retired before them.

Rosewell thinks we still haven't faced up to the burden this will lay on future workers. This week the Office for National Statistics described the rise in the number of over-85s as "a time bomb". Longevity and demography will combine to increase the ratio of over-65s from 16% now to almost 23% by 2032. That shift will make today's long retirements unsustainable for future generations. Why, then, should the young agree to labour for ours?

It is quite possible that they will simply refuse to do so. They may rewrite the terms of the generational bargain. In recent years those getting older have become increasingly demanding of government, and indignant about its failure to provide more for them - in campaigns for free social care and against the selling of homes to fund old-age care, for instance. The feeling is that making individuals pay isn't fair, and that the state should provide. But the state is only a collection of individuals, and if I want free care, some younger, fitter person will have to pay for it.

Politicians find these questions of intergenerational conflict very difficult. They would prefer to evade them, especially when they involve large and politically active constituencies. That's why the government was slow to introduce even Adair Turner's relatively modest proposals; why it backed away from substantial reform of public sector pensions; and why it decided to make students pay for university, rather than impose a retrospective graduate tax on those who had already benefited. But we can't afford this kind of myopia. What's the right balance over our lifetime between working and dependence, and how should we balance the competing interests of generations at a time of chaos, cuts and profound change? We all have a profound interest in the answers.

jenni.russell@theguardian.com