Bill Gates says reducing greenhouse gas emissions to zero by 2050 "will be the hardest thing humanity's ever done", but could potentially be achieved with the use of nuclear power.

In an interview with 7.30, the Microsoft co-founder set out his thoughts on how to reach zero emissions in 30 years.

"This will be the hardest thing humanity's ever done because the physical economy — cement, steel, transportation, agriculture — all of these sectors will have to make changes," he said.

"Only by being focused on innovation and scaling with the right policies on a global basis can we achieve [that]."

Mr Gates told 7.30 the cost of "going green" globally would be over $5 trillion, unless there is new technology to help.

Like swapping petrol with electricity to power cars, Mr Gates wants to see other emissions-intensive energy sources replaced.

He said that as solar and wind were intermittent and not reliable year-round, nuclear power was a practical option.

"We either need a miracle invention to make batteries that are 20 times cheaper, so you can do that seasonal storage, so when you get a few weeks where [solar and wind] sources aren't there, you still can keep people warm," he said.

"Or, you need 25 per cent of your generation to be available, independent of the weather, and nuclear fission and fusion are really the only things that can work at that scale."

The software developer turned philanthropist wants to see cheaper and safer nuclear power made, but questions whether it would be popular as a solution.

"We'll have to see. If that's the path to solve climate, can we get the public to accept it?" he said.

'Thirty years enough time' to transition jobs

Mr Gates also urged political parties to agree with the goal of net zero carbon emissions, even if they disagree on how to get there.

Prime Minister Scott Morrison recently refused to commit to the target within the next 30 years, despite more than 70 other countries doing so.

"I wish that all political parties would agree with the goal," Mr Gates told 7.30.

"They might disagree about how to put the resources in ... But if you have parties that don't accept the goal, then you know, it's unlikely we'll get there."

Mr Gates acknowledged that industries such as oil, gas and coal will see a downturn from a focus on reducing emissions. But he remains optimistic that a 2050 target allows enough time to transition jobs.

He hopes to see existing skills transferred to making green hydrogen or building new infrastructure.

"We have to make sure communities don't feel like they're completely left out of this plan," he said.

"Thirty years is enough time that we ought to be able to plan that transition."