The world looks different from the east than from the west. One thing is clear following the G20 summit in Seoul. It is that the perceptions of the causes of the recession in the emerging economies and in the developed world are quite different. Indeed for much of the developing world there has been no recession at all.

It is an important difference because it leads to different policy prescriptions. Is the principal problem that the west went on a consumption binge financed by borrowing? Or is it that the east used the fact that many of its currencies are undervalued to boost its own growth at the expense of the rest of the world?

Everyone agrees there are global trade and payments imbalances that are unsustainable, but until you can agree on the causes it is impossible to agree on a treatment. But if you start from the data, some things do become evident. One is that current account imbalances are a problem for the US more than for the developed world as a whole. The US current account has not been in surplus since the early 1990s and it deteriorated in pretty much a straight line until 2006, when the deficit exceeded 6% of GDP. As the recession stuck and import demand was curbed there was a sharp improvement but the gap remained above 2% of GDP. Now that the economy is growing again the deficit has started to widen.

The rest of the developed world has remained close to balance or in modest deficit for the past 20 years. This is remarkable because that period has included the early 1990s recession, the early 2000s slowdown and the most recent crisis.

If you take the emerging economies over the same period there was a gradual shift from deficit to a large surplus but that surplus has now come right down. You could make a case that the emerging countries exploited their position as exporters during the boom, but it is rather harder to make that case now.

But before anyone concludes that the adjustment is well and truly under way, note the different amounts of slack in the economies of the developed world vis-à-vis the emerging world. The developed world, apart from the US, is running way below capacity and the US is running with even more slack than the rest. But the emerging world is, if anything, running ahead of sustainable capacity.

Now the point here is that, as we in the west return to full demand, we will tend to suck in more imports. Meanwhile the east is in surplus even when running at pretty much full speed. The imbalances have been corrected to a fair extent but only because we are still way below full output. So there is still a structural problem.

What should be done? One option would be a further dollar devaluation, particularly against emerging market currencies. A second shift would be a sustained boost to US and other developed market demand, which will presumably require continued easy money policies. And the third would be some modest curb on demand in the emerging world.

That all sounds hunky-dory until you look at the practical difficulties. For a start, the emerging markets, particularly China, will resist a revaluation. China is desperately anxious to avoid what it sees as the mistake of Japan in allowing its currency to become overpriced. The other difficulty is how to boost demand in the developed world, given the debt we are all carrying. The least indebted of the G7, Germany, is carrying nearly double the debt of the most indebted of the large emerging countries, China.

Put this way, there is no easy solution. Whatever else happens there will have to be a rise in the emerging market currencies. But there is also a responsibility of the developed world to boost demand.

A decade ago, after the Asian and Russian debt crises, the west could assume it would be listened to. That has changed. Why should countries that have had a good crisis take lessons from those that have had a bad one?