One Nation leader Pauline Hanson has taken aim at 16-year-old Swedish climate activist Greta Thunberg after she berated world leaders at a UN climate summit.

Ms Thunberg gave an impassioned speech at the United Nations Headquarters on Monday, urging countries to take stronger measures to combat climate change.

READ MORE Watch Greta Thunberg’s full speech to world leaders at the UN

But Senator Hanson dismissed the speech on Wednesday, saying she "wasn't impressed".

"I think that she's basically a teenager who has had no life experiences. She was actually voicing what other people have put into her head," Senator Hanson told Sky News.

"I blame the adults around her for allowing this to happen."

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The One Nation leader also criticised the masses of students who held climate strikes around the world last week, including hundreds of thousands in Australia.

"What children are being taught in schools is very biased, it's not a balanced view ... This should be stopped in our education system," she said.

READ MORE Australia’s climate protesters get creative with their signs

"Especially in the climate change rally that they had, how much effort would these kids put into it if they had to go on a weekend, their own time?

"It was great to take a day off from school. It was hyped up by the media, by everyone, but I think it's disgraceful."

Government MPs criticise Greta

A number of government MPs have also slammed the 16-year-old.

Queenslander George Christensen changed his Facebook profile picture to a photo of Ms Thunberg crossed out, with the text "GRETA FREE ZONE".

Facebook

And Sutherland Shire MP Craig Kelly posted on Facebook, "this child has no comprehension or understanding whatsoever of how free markets and fossil fuels she condemns".

"Her childhood has been stolen by alarmists that have brainwashed her."

In another post, he wrote, "SOMEBODY SHOULD BE ARRESTED FOR CHILD ABUSE".

"The eyes of all future generations are upon you. And if you choose to fail us, I say we will never forgive you."



-- @GretaThunberg at UN #ClimateAction Summit. https://t.co/g4uXzT9aRM pic.twitter.com/2nBzFxsnxP — United Nations (@UN) September 23, 2019

Speaking from New York, Prime Minister Scott Morrison cautioned against imposing "needless anxiety" on children when dealing with the concerns of climate change.

"We have got to caution against raising the anxieties of children," he said.

"But I do understand that people do feel strongly about this ... I want children growing up in Australia to feel positive about their future."

'How dare you'

Ms Thunberg's speech made headlines around the world, with some hailing the only four and a half minutes as a major moment for the climate movement.

"I shouldn't be up here. I should be back at school on the other side of the ocean," she told the UN.

READ MORE 'Seems like a happy young girl': Trump slammed for mocking Greta Thunberg

"You come to us young people for hope. How dare you?

"We are in the beginning of mass extinction, and all you can talk about is the money and fairy tales of eternal economic growth. How dare you."

Last Friday over 4 million people striked for the climate.

This Friday we do it again!

170 countries and 6383 events so far in #weekforfuture

Find or register your strike at https://t.co/G06WbXNvl1 or local websites.

Spread the word!#FridaysForFuture #ClimateStrike pic.twitter.com/VXCnPQzw6a — Greta Thunberg (@GretaThunberg) September 25, 2019

The world's top scientists believe long-term temperature rise must be limited to 1.5 degrees Celsius over pre-industrial levels to prevent runaway warming with catastrophic effects.

But rather than peaking, the level of emissions being released into the atmosphere are at an all-time high, triggering global weather hazards from heat waves to intense hurricanes and raging wildfires.

Additional reporting: AFP