WASHINGTON/BANGKOK: World leaders pledged last week to step up efforts to reach a UN deal to fight climate change, but they will have to match rhetoric with rapid action to break a crippling deadlock before a December deadline.

With only two and a half months to go before 190 nations gather in Copenhagen to forge a successor to the emissions-capping pact known as the Kyoto Protocol, urgency for a breakthrough on key topics of disagreement is growing.

Progress on those outstanding roadblocks did not emerge from meetings at the UN climate change summit or at the G20 summit in Pittsburgh. Industrial and developing nations remain at odds over how to spread out greenhouse gas emission curbs. Besides, the issue of climate finance - aid from industrial countries to developing nations dealing with climate change - went largely untouched.