The G20 has served its purpose and should be replaced

The G20 - a self-selected oligopoly
The G20 is unsustainable as a global governance body. With 174 UN member states permanently excluded, the G20 fails to meet widely accepted criterion of representation. In the absence of objective criteria for membership, the G20 is little more than a self-selected oligopoly.

But criticism of the G20 - whether in terms of its lacking representational legitimacy or its limited effectiveness in dealing with global economic governance issues - is often met with 'there is no alternative'.

An alternative to the G20
In these papers, Jakob Vestergaard and Robert Wade step by step outline a promising alternative, namely a Global Economic Council. The council should be created by starting from the constituency system of the Bretton Woods organizations (World Bank and IMF).

This system contains a representational mechanism incorporating all the member states. However, it has some evident flaws, and the authors describe how it should be modified to make it more equitably representative. All three bodies should then have the same constituencies. With its constituencies being congruent with those of the Bretton Woods organization, the Global Economic Council would have stewardship of the Bretton Woods organizations, enabling it to move beyond the current G20's 'talk shop' role.

Embedding a Global Economic Council in the Bretton Woods system - and at the same time updating the voting system of the Bretton Woods institutions - would significantly improve the legitimacy and effectiveness of global economic governnance.

Note the DIIS Seminar on this subject:
G20 at a Crossroads
Wednesday, 2 November 2011, 14.00-16.30