Reuters: The world’s largest exchange for carbon emissions trading is caught in the crossfire of a battle between two of its business partners that could result in it losing a substantial portion of its trade to rivals. In recent days some of the largest carbon credit brokers have come out in favour of two new challengers to the European Climate Exchange (ECX), which does around 80 percent of the exchange-based trade in carbon credits. One of ECX’s partners, its clearinghouse provider …