Reuters: A cut-throat battle is emerging to dominate trade in permits to emit greenhouse gases, which could grow to rival the $3 trillion oil trade, with dominant exchanges eventually expected in Europe, the U.S. and Asia. Emissions exchanges are the hubs of a growing, $60 billion carbon market, where companies buy and sell permits to emit harmful greenhouse gases like carbon dioxide, and are expected to consolidate as a global market emerges, analysts say. London will remain the …