Swedish climate and environmental activist Greta Thunberg denounced the world’s “so-called leaders” during a speech at Italy’s Youth4Climate summit on Tuesday, accusing politicians of failing to act on climate change and describing their promises as 30 years of “blah blah blah.”

Removing her mask so she could deliver an impassioned speech on the podium in Milan, 18-year-old Thunberg said that despite countries around the world vowing to meet “ambitious targets,” the climate crisis was continuing to escalate.

“Build back better, blah blah blah,” she said, referencing the words of President Biden and British Prime Minister Boris Johnson, who have often used the phrase when talking about their visions for the future.

Thunberg also resurfaced past remarks from French President Emmanuel Macron, who said in a warning to Congress during the Trump presidency in 2018 that there “is no planet B,” while calling on countries to “work together” to reduce carbon emissions and save the planet.

Mimicking Macron during the conference Tuesday, Greta said: “There is no planet B. There is no planet blah.”

Such words uttered by leaders, she said, sounded “great” but had so far led to “no action.”

“Our hopes and dreams drown in their empty words and promises,” she said, addressing an audience of an estimated 400 activists ages 15 to 29. She encouraged world leaders to find a “smooth transition towards a low-carbon economy.”

The activists at the youth summit will create a list of recommendations that will be reviewed by government officials and taken to the 2021 United Nations Climate Change Conference, or COP26, in November.

Ugandan climate activist Vanessa Nakate also spoke at the summit, saying that vulnerable countries were “still waiting” on funds of 100 billion euros, or $117 billion, that were promised by officials in 2020.

“It’s time to show us the money. It’s time, it’s time, it’s time,” she said before breaking down in tears after sharing that she had recently witnessed police in Uganda removing a body from floodwaters.

The younger generation has repeatedly called on those in power to meet climate targets, citing reports that deem their futures uncertain amid an ever-warming planet. A survey earlier this month found that more and more people saw climate change as a looming threat — with young people particularly worried about it harming them.

Thunberg’s blistering attack comes following a period of extreme weather that wreaked havoc globally this summer, claiming more than 150 lives during massive floods in Germany and Belgium and forcing temperatures to climb into triple digits as a heat wave swept the Western United States and Canada.

In an August review of climate science, a panel from the United Nations warned that this summer’s extreme weather had been intensified by human-caused climate change and that heat waves, floods and fires would worsen in the coming decades.

In the same report, scientists projected that the Earth could warm up to another 6 degrees by the end of this century if emissions of heat-trapping gases are not reduced.

“With every additional increment of global warming, changes in extremes continue to become larger,” the report said.

On social media Wednesday, many praised Thunberg’s speech, calling her “brave” and “brilliant.” Some critics, however, labeled her “blah blah blah” comments as “absurd.”

Thunberg has long campaigned for a better future for the planet and called out politicians for not acting swiftly enough to tackle the crisis. She encouraged those listening to her speech to remain hopeful, adding that change was “not only possible, but urgently necessary.”

COP26 is set to take place in Glasgow, Scotland, in November. The conference will welcome leaders, scientists and campaigners as they address the climate crisis and the goals of the Paris agreement.

At COP26, officials are expected to present 2030 emission reduction targets, which include curtailing deforestation and working to phase out coal. Countries are also being asked to work toward protecting the world’s ecosystems and building defenses that protect communities impacted by climate change.