Sarah Harper sums up the this century's greatest challenge in a single sentence: In 20 years' time half the population of Europe will be aged over 50.
And, the US won't be far behind.
Having said that, 50 ain't what it used to be. Fifty isn't the new forty, it's the new thirty. The sooner our state-funded pensions (like social security) figure this out and appropriately increase the retirement age, the better off we'll all be.