There was a climate change showdown on Q&A last night when Professor Brian Cox and One Nation Senator Malcolm Roberts were guests on the panel.

Here's the best bits from their exchanges for you.

The night began with an audience question to the British physicist, asking him to address Senator Roberts' request for proof of a human element in climate change.

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Here's how Professor Cox responded:

"This is now a clear global problem. The absolute, absolute consensus is that human action is leading to an increase in average temperatures. I know you (Roberts) may try to argue with that, but you can't."

Round 1: A pause in global warming

Here's how Senator Roberts began his response:

"We've had a pause in this so-called warming for now 21 years, depends how you measure it, 21 years. "Now I'm absolutely stunned that someone who inspired by Richard Feynman, a fantastic scientist who believes in empirical evidence, is quoting consensus."

Professor Cox:

"I brought the graph. "Let me tell you where the pause is. The pause that's often quoted, if you take this point here, which is about 1997, I think, and you ignore 2015-2016. You can choose that point and you can draw a slightly straighter trend line on there. But that's a misunderstanding."

Professor Brian Cox wasn't kidding. He brought the graph.

Round 2: A NASA conspiracy?

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After some back and forth between the two, Q&A host Tony Jones stepped in:

"Malcolm, you are hearing the interpretation of a highly qualified scientist and you're saying, "I don't believe that" — is that right?"

Senator Roberts:

"I'm saying two things. First of all, that the data has been corrupted and we know..."

Professor Cox:

"What do you mean by corrupted? What do you mean?"

Senator Roberts:

"Been manipulated..."

Professor Brian Cox:

"By who?"

Senator Roberts:

"By NASA..."

Professor Cox:

"NASA?!"

The audience began to laugh.

Tony Jones

"We have to hear what is being said here. It is all very well to laugh but we have to hear what is being said."

Senator Roberts:

"Steve Goddard has shown the NASA figures and the graph was originally showing the 1930s were warmer than recent decades and that is correct. People have recognised that for many years. In the recent years they've been reversed so that the 1930s were reduced in temperature and the later periods were inflated in temperature. That's a fact. The Bureau of Meteorology is exactly the same. Greg Hunt squashed an investigation of the Bureau of Metrology earlier this year."

Professor Cox asked Senator Roberts if he believed in the moon landing before delivering his point:

"The idea that NASA — I should say to people, by the way, the Australian Academy of Science have done a brilliant — you can never get any sense on programs like this (Q&A), they're adversarial, but the Australian Academy of Science report is superb. I've brought it because I'm going to come and give it to you in a minute for you to have a read. The accusation that NASA, the Australian, the Met Office in the UK, everybody is collaborating to manipulate global temperature data..."

Malcolm Roberts:

"Are you accusing me of saying they're collaborating?"

Professor Cox:

"What, they've all manipulated it in the same way and accidently got to the same answer? Is that what you're saying?"

Round 3: The models

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Professor Cox says we need to know what will the world be like in 2050, 2075, 2100:

"If you don't model it. How can you go about trying to answer the question?"

Senator Roberts:

"You answer the question by making projections based on models providing the models are validated and proven to be accurate. And the models have already been proven to be inaccurate and the IPCC (Intergovernmental Panel on Climate Change) has recognised that and admitted it." "Now what we need to do is look at the empirical data. And the empirical data says quite categorically that the levels of carbon dioxide in the atmosphere are a result of temperature changes, not caused."

Professor Cox:

"That's flat out wrong. That's a deception. It is flat out incorrect. "I took a snapshot of the different bits of evidence for 2015. Global upper ocean heat content highest on record in 2015. Global sea level, highest on record in 2015, 70mm higher than that observed in 1993. Global surface temperature highest on record, El Nino something like a 10-40 per cent contribution to that. Tropical cyclones well above average overall. "The key point is if you don't accept that the only way to try to formulate policy on what we do with emissions is to build models, that's the only way you can predict the future otherwise you have tarot cards and tea leaves."

Who are they?

Professor Brian Cox is a particle physicist and science communicator, best known for his BBC shows including Wonders of the Universe and Wonders of Life. (He's also a former pop musician but that's by the by.)

One Nation's Malcolm Roberts will represent Queensland in the Senate. He's worked in coal mining and has an honours degree in engineering and a masters degree in business administration.