Australia isn't just squandering its unique economic opportunity from emissions reduction, economist Ross Garnaut says it is also discouraging other countries from ambitious action on climate change.

The eminent economist, writing in The Sydney Morning Herald and The Age on Friday, said Prime Minister Scott Morrison's recent remarks about "evolving" climate policies were a welcome progression in public debate, but tangible reform is needed to overturn Australia's negative influence on international climate action.

Professor Ross Garnaut says Australia is squandering economic opportunities in emissions reductions. Credit:Wayne Taylor

"Those favouring strong action everywhere are helped by the knowledge that other countries are doing their fair share. Those resisting strong action in all countries make much of the inadequate efforts of Australia," Professor Garnaut said.

"Australia's 2030 target is the weakest of the developed countries and that makes us a drag on the global effort."