The trouble with these are that they are all, as the finance guys like to say, "priced in." In other words, investors and money managers have some sense of the magnitude of risk involved and are hedged accordingly.

Are there any low-probability, high-impact events the markets might be missing? I can think of five big ones that aren't "priced in" as much as they might be:

1) Another 9/11.

2) An avian flu pandemic.

3) A computer virus that shuts down Google.

4) A U.S.-China clash over Taiwan.

5) A worldwide political shift to the left.

It's No. 5 that really interests me because it's actually a high-probability, high-impact event. Indeed, it's not just high probability. It's already happening.

The headline event has been the decision by newly elected Bolivian President Evo Morales — predicted in this column Feb. 13 — to nationalize his country's energy sector.

But the swing to the left is not a purely Latin American story. The left won last month's Italian elections. The French government recently caved in to street protests by trade unions and leftist students. And in the United States, the Democrats are poised to make gains in the November midterm elections.

The reason so many commentators are missing this political shift is that, as relatively high earners, they are mostly cut off from its social drivers.

Driver No. 1 is inequality, which has risen quite markedly within most economies in the last decade, mainly because tax systems have become less progressive and the fruits of the world's rapid growth have been disproportionately distributed to the owners of corporations and the executives who run them.

Income distribution in the U.S. has not been this unequal since before World War II — the last time that the top 1% of earners accounted for more than 14% of all income (excluding capital gains). The average pay for a chief executive in the U.S. increased 27% last year to more than $11 million. By contrast, the average wage earner took home less than $45,000 in 2004, up roughly 3% from the year before.

In 1940, the average top executive's salary was about 68 times the average worker's earnings; now, it's more like 200 times higher.

The second driver of the swing to the left is ethnic conflict. Take the issue of immigration. You might think rising immigration would lead to a backlash on the right, not the left, and you'd be right. But the net effect of xenophobia — which is most likely to be felt by blue-collar, indigenous voters — is often to benefit the left because it tends to split the right.

That's already detectable in North America and continental Europe. It could prove to be true in Britain too.

Granted, last week's front pages in Britain were dominated by Labor's heavy losses in local elections. But the real story was that the far-right British National Party won 11 of the 13 seats it contested in East London.

According to opinion polls, about a third of British voters now regard immigration as the most important issue facing the country. Polls taken before last week's elections revealed that 24% of likely voters had considered, or were considering, voting BNP. If there had been more BNP candidates last week, it seems certain, there would have been more BNP votes. And not all of them would have been taken from Labor.

No trend is ever universal, of course. But history would lead us to expect that a period of widening inequality be followed by a bout of political populism.

There are many reasons to be cheerful these days, as I said. But not everyone is cheerful, especially the further down the income pyramid you go. And that's an opportunity for a new generation of political leaders.