A motion declaring Australia is facing a climate emergency has passed the upper house of the South Australian parliament.

Moved by Greens MP Mark Parnell, the motion also recognises that climate change is already costing lives and destroying vital ecosystems around the world.

In the video above: PM hits back at climate change critics

"The call for governments to do more to tackle dangerous climate change is growing around the world including from hundreds of thousands of school children around Australia who went on strike last week over climate inaction," Parnell said.

The Greens will continue to push the state government to wean SA off fossil fuels, starting with a ban on all new fossil fuel projects, including in the Great Australian Bight.

"The first step is to recognise that you have a problem, the next step is to do something about it," Parnell said.

Morrison hits back

Scott Morrison has warned against creating "needless anxiety" in children about climate change.

The prime minister says he always likes to make sure his own daughters, aged 10 and 12, have perspective and context on the issue.

"I think there's a lot of disinformation out there about, frankly, what Australia is doing," he told reporters in New York overnight.

"I want children growing up in Australia to feel positive about their future.

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"And I think it's important that we give them that confidence that they will not only have a wonderful country and pristine environment to live in but they'll also have an economy they can live in as well."

Youth climate activist Greta Thunberg lambasted world leaders in her address to the UN summit this week, which Mr Morrison missed while he gave a speech in Chicago.

"People are suffering. People are dying. Entire ecosystems are collapsing. We are at the beginning of a mass extinction - and all you can talk about is money and fairytales of eternal economic growth," she said.