Dani Rodrik in Project Syndicate:
The G20 has its origins in two ideas, one relevant and important, the other false and distracting. The relevant and important idea is that developing and emerging market economies such as Brazil, India, Indonesia, South Africa, and China have become too significant to be excluded from discussions about global governance. While the G7 has not been replaced – its last summit was held in May in Sicily – G20 meetings are an occasion to expand and broaden the dialogue.
The G20 was created in 1999, in the wake of the Asian financial crisis. Developed countries initially treated it as an outreach forum, where they would help developing economies raise financial and monetary management to the developed world’s standards. Over time, developing countries found their own voice and have played a larger role in crafting the group’s agenda. In any case, the 2008 global financial crisis emanating from the United States, and the subsequent eurozone debacle, made a mockery of the idea that developed countries had much useful knowledge to impart on these matters.
The second, less useful idea underpinning the G20 is that solving the pressing problems of the world economy requires ever more intense cooperation and coordination at the global level. The analogy frequently invoked is that the world economy is a “global commons”: either all countries do their share to contribute to its upkeep, or they will all suffer the consequences.
More here.