Public debt: The biggest bill in history | The Economist:
"Not since the second world war have so many governments borrowed so much so quickly or, collectively, been so heavily in hock. And today’s debt surge, unlike the wartime one, will not be temporary. Even after the recession ends few rich countries will be running budgets tight enough to stop their debt from rising further. Worse, today’s borrowing binge is taking place just before a slow-motion budget-bust caused by the pension and health-care costs of a greying population. By 2050 a third of the rich world’s population will be over 60. The demographic bill is likely to be ten times bigger than the fiscal cost of the financial crisis."
One simple answer ... raise the retirement age.