An opposition MP says humans are not causing climate change, and pointed to Adolf Hitler as an example of how scientists can be wrong.

Liberal MP Dennis Jensen's comments come days after his leader Malcolm Turnbull promised a greener climate change policy than the government's.

Dr Jensen cast doubt on the apparent scientific consensus that humans are affecting the climate.

"Albert Einstein was very much criticised by Hitler, and Hitler actually had a group of 100 top scientists in Germany write a book called 100 scientists against Einstein," Dr Jensen told reporters in Canberra.

"Einstein was asked: 'Doesn't it bother you Dr Einstein that you've got so many scientists against you?'

"And he said: 'It doesn't take 100 scientists to prove me wrong, it takes a single fact'."

Dr Jensen, who has a PhD in the physics of ceramics, said he was a climate change sceptic.

Mr Turnbull says humans are affecting the climate and the problem must be addressed.

Dr Jensen said he differed with his leader on that.

Mr Turnbull has promised to set a deeper target to cut greenhouse gas emissions than the government.

"This is something that's still got to be discussed in the party room," Dr Jensen said.

When asked how reporters should sum up the opposition's climate change policy, the West Australian MP said: "I'll leave that to you to determine".

Dr Jensen on Wednesday launched an online petition which says the world is not warming at an unusual rate, and emissions trading should not go ahead.

Climate Change Minister Penny Wong called on Mr Turnbull to deal with Dr Jensen.

"Mr Turnbull knows it's the right thing to do to act on climate change," she told reporters in Canberra.

"It's up to Mr Turnbull to pull his people into line."