China and Brazil agreed on Tuesday to swap up to the equivalent of $30 billion in each other\'s currencies if need be so that their fast-growing commercial ties will not suffer if a new banking crisis causes dollar trade finance to dry up, Reuters reported. The three-year agreement, signed before the start of a BRICS nations summit in Durban, South Africa, marked a step by the two largest economies in the emerging powers group to change global trade flows long dominated by the United States and Europe. Brazil, Russia, India, China and South Africa represent together a fifth of global GDP but have struggled to convert their economic weight into political clout in the international arena Bilateral trade totalled around $75 billion last year. Of Brazil\'s $41.2 billion exports to China, iron ore accounted for 34 percent, while soy and soy products made up 29 percent and crude oil 12 percent. Electronics, machinery and manufactured goods figured heavily in Brazil\'s $34.2 billion of imports from China. Brazilian officials have said they hope to have the trade and currency deal operating in the second half of 2013.