Whatever happened to global governance. The Group of 20 was supposed to answer the question of our times – how do rich and rising nations manage competing and coincident interests in an interdependent world? The best that the G20 leaders could come up with the other day was polite agreement to disagree.

Heady talk of a new international architecture stirred by last year's London G20 gathering is long behind us. There have since been three big global challenges on the agenda – about the shape of the financial system and the path of economic recovery, about climate change and about trade.

On the first, as we saw at the weekend G20 gathering in Toronto, governments are mostly going their own ways, albeit with elements of bilateral co-operation. Barack Obama, I heard this week in Washington, thought the summit pretty much a waste of time.