By Jean Pisani-Ferry

As the collapse of the trade talks in Geneva in July made clear, there is no longer any meaningful trade negotiation without the main nations from the emerging world. The year 2008 may go down in history as the one in which rich countries discovered that this applies to macroeconomic policies, too.

In January it looked as if the opposite lessons could be drawn from events. For a while, Ben Bernanke at the US Federal Reserve and Jean-Claude Trichet at the European Central Bank seemed to be the only relevant policymakers in the world – and they were, as far as liquidity strains were concerned, if only because the US and Europe account for about two-thirds of the global supply of financial assets.

But as months went by, it became clear that countries affected by the shock represented merely a half of world gross domestic product, two-fifths of global energy demand and not even a third of world cereal consumption. Furthermore, rich countries have significantly less weight at the margin: their contribution to world growth is about half their share of world GDP, so one-quarter of the total, and the same rule of thumb applies even more to the demand for oil and foodstuffs. So in the market for scarce commodities, the effects of the slowdown in the US and Europe were offset by domestic booms in the emerging world.

The remainder of this column can be read here. Debate from our expert panel appears below.