Swedish climate activist Greta Thunberg stunned the audience at the recent Youth4Climate conference and people all over the internet with her speech at the gathering, held in Milan earlier this week.

In her comments, Thunberg lambasted world leaders, including Democratic President Joe Biden and U.K. Prime Minister Boris Johnson, accusing them of being all talk and no action with their climate change policies.

Riffing on famous quotes and catchphrases from the two leaders, Thunberg openly mocked the two men in a way that had many people cheering.

See her comments below.

In her speech to some 400 15-29-year-old attendees from 186 countries, Thunberg began by calling for green economic policies and assuring the 400 attendees, all between 15 and 29 years old and hailing for 186 countries, that we can tackle climate change if we all pull together.

That sentiment provided a perfect segue into speaking truth to power, criticizing54 world leaders' who seem forever resistant to tackling the problem of climate change with anything other than lip service.

As Thunberg put it:

"There is no 'planet B.' There is no 'planet blah.' Blah blah blah, blah blah blah."

She then laid into U.K. Prime Minister Boris Johnson, mocking his now infamous quote from President Biden's virtual climate summit earlier this year, which many interpreted as patronizing lip-service about fighting climate change.

"This is not about 'some expensive, politically correct act of bunny hugging' or blah blah blah."

Thunberg then took aim at Biden, mocking his signature budget and economic recovery legislation, "Build Back Better."

"Build Back Better, blah blah blah."

While "Build Back Better" does include climate change initiatives, activists and scientists alike have roundly criticized it for exactly the same shortcomings Thunberg pointed out in her speech: Biden's initiatives are too little, too late and don't at all accord with the level of crisis even Biden himself admits is befalling the world.

Or, as Thunberg went on to say:

"Green economy. Blah blah blah. Net zero by 2050. Blah, blah, blah."

"This is all we hear from our so-called leaders. Words that sound great but so far have not led to action.

"Our hopes and dreams drown in their empty promises."

On Twitter, many applauded Thunberg's straight-talking truth-to-power approach.

Thunberg's speech went on to issue a dire warning to world leaders, who are set to meet in Glasgow in November for the COP26 conference, the largest gathering of world leaders to address the climate change emergency since the 2015 Paris agreements.

"We can still turn this around – it is entirely possible. It will take immediate, drastic annual emission reductions. But not if things go on like today."

"Our leaders' intentional lack of action is a betrayal toward all present and future generations."

Here's hoping they take her words to heart.