THE G20 group of nations, which is meeting this week in the French city of Cannes, is a big improvement over the G7 because it takes emerging economies seriously. But do the emerging economies themselves take the G20 seriously? At last year’s summit in Seoul, members made a host of commitments on exchange rates, trade, financial reform and so on. Some countries stuck to these commitments better than others, according to the latest ranking by the G20 Research Group, based at the University of Toronto’s Munk School of Global Affairs. Five of the top seven countries in their ranking are members of the G7. Conversely, the bottom six places were all occupied by emerging economies. This suggests the members of the old club are taking the new club more seriously than the countries it was designed to include. The gap between word and deed was greatest in Argentina, which has imposed no fewer than 21 trade barriers since the Seoul summit, covering a range of imports from apples and pears to Christmas trees and burglar alarms.