#FridaysforFuture leader Greta Thunberg addressed the UK parliament this week, attended a roundtable with national party leaders that included an empty seat for absent Prime Minister Theresa May, and backed a general strike as the next step in mobilizing public response to the “existential crisis” of climate change.

“People are slowly becoming more aware, but emissions continue to rise. We can’t focus on small things. Basically, nothing has changed,” Thunberg told an Earth Day event in London, adding that the student movement sweeping the world needs the support of older generations to hold elected officials accountable.

“This is not just young people being sick of politicians. It’s an existential crisis,” she said. “It is something that will affect the future of our civilization. It’s not just a movement. It’s a crisis, and we must take action accordingly.”

In her speech at Westminster Tuesday, Thunberg took aim at the “very creative” accounting that has enabled the UK to claim carbon pollution reductions while pushing ahead with shale gas fracking, new oil production from the North Sea, and gas fields and expanding airports.

“This ongoing irresponsible behaviour will no doubt be remembered in history as one of the greatest failures of humankind,” she said, noting that the country’s vaunted 37% emission reduction since 1990 falls to 10% after factoring in aviation, shipping, imports, and exports.

UK Environment Secretary Michael Gove admitted that “we have not done nearly enough”, adding that “the time to act is now, the challenge could not be clearer—Greta, you have been heard.” In her speech, Thunberg told parliamentarians that “you don’t listen to the science because you are only interested in the answers that will allow you to carry on as if nothing has happened.”

At the Earth Day event hosted by the Quakers and Guardian Events, while participants focused on various lifestyle changes to reduce personal carbon footprints, Thunberg “put the focus on challenging the companies and governments that are responsible for the bulk of emissions,” The Guardian reports. “How to deal with people in power was a frequent subject of questions to the panel. Thunberg said her autism helped her filter out much of the greenwashing.”

“We are more likely to see through lies,” she said. “We don’t follow the stream. You can’t be a little bit sustainable—either you are sustainable or you are not.”

Asked how she deals with climate deniers, Thunberg was succinct: “I don’t.” Asked by the BBC what she would say if she met Donald Trump, she replied that “I can’t really say anything to him that he hasn’t heard before. Obviously, he’s not listening to the science and to what we have to say, so I wouldn’t be able to change his mind.”

During the Earth Day event, Thunberg fielded questions from younger children, who asked how much time humanity has left and whether there’s still time to stabilize the climate. “Of course we can,” she replied. “It’s physically possible, the scientists say. It’s up to us. If we do this now, then of course we will. But if we don’t, we might not do it. But yes, definitely we can.”

Thunberg’s visit to London came during a wave of Extinction Rebellion (XR) protests that blocked streets, bridges, and local landmarks and resulted in more than 1,000 arrests. Earlier today, five men and women clad in black suits and red ties glued themselves to the entrances of the London Stock Exchange as part of a demonstration at the London financial district, The Independent reports.

In a final day of protests, XR announced roadblocks in different parts of the city, while calling off its blockades at Parliament Square and Marble Arch.

“We would like to thank Londoners for opening their hearts and demonstrating their willingness to act on that truth,” XR said in a statement. “We know we have disrupted your lives. We do not do this lightly. We only do this because this is an emergency.”

The group added that, “around the planet, a long-awaited and much-needed conversation has begun. “People have taken to the streets and raised the alarm in more than 80 cities in 33 countries. People are talking about the climate and ecological emergency in ways that we never imagined.” And “it is now time to go back into our communities, whether in London, around the UK, or internationally,” ahead of another round of protests in the near future.

The Guardian reports that public backing for XR quadrupled during the nine days of action, with the group drawing 30,000 new supporters or donors and raising £200,000, mostly in increments of £10 to £50. “What this shows is that Extinction Rebellion has spoken to people who have been wanting to act on this for such a long time but haven’t known how,” an XR spokesperson stated. “The debate on this is over—ordinary people are now saying it is time for politicians to act with real urgency.”

The protests gained support in an open letter from 21 UK business leaders, including a former Unilever CEO, the corporate social responsibility director at The Body Shop, and green energy entrepreneurs Dale Vince and Jeremy Leggett.

The head of Nordea Bank, one of Europe’s biggest ethical investment funds and the Nordic region’s third-largest corporation, said the week of protest was just the start. “If we talk about the number of millennials in Europe and in countries all over the world, they are very concerned about the situation and I don’t think they feel that they have too many other tools in their hands to approach this,” Sasja Beslik told the BBC.