The federal opposition's climate change spokesman says the coalition will never introduce an emissions trading scheme.

"I don't see it's ever likely to happen," Liberal frontbencher Greg Hunt told ABC TV on Monday night.

Mr Hunt said Canada had recently rejected a carbon tax and China "is not going anywhere near this".

He said the Gillard government's scheme to address climate change was an "electricity tax and gas tax" and he denied it was reducing carbon emissions.

"I can guarantee you that China will not be imposing a nationwide electricity, energy and gas tax," Mr Hunt said.

China has announced a progressive rollout of pilot emissions trading schemes, including Beijing, Shanghai and Guangdong, which cover more than 100 million people.

Health Minister Tanya Plibersek said Opposition Leader Tony Abbott "described himself as a weathervane on climate change and then said it was bull***."

"This is the man who wants to be prime minister, take that with a grain of caution," she told ABC TV.

She said emissions had come down by 8.6 per cent since a price on carbon pollution was introduced.

Ms Plibersek said by the end of the year one billion people will be living in a country, city or state with an emissions trading scheme or carbon price.

Last week, US President Barack Obama urged Congress to introduce a market-based mechanism to tackle climate change.