Former US president Barack Obama met with teenage climate activist Greta Thunberg on Monday, describing her as “one of the planet’s greatest advocates”.

The pair discussed the school strikes for which Thunberg achieved fame, with the Swedish activist praising the enthusiasm of the schoolchildren who gathered to protest in Washington and New York.

Following this seemingly cordial exchange, the 16-year-old attended a meeting of the senate climate change task force, where she rebuffed lawmakers’ praise and accused them of not trying hard enough to address the climate crisis.

Co-sponsor of the green new deal bill, Ed Markey, told the activist: “We need your leadership. Young people are the army politically, which has arrived in the United States. You put a spotlight on this issue in a way that it has never been before, and that is creating a new X factor.”

“Please save your praise. We don’t want it,” Thunberg replied. “Don’t invite us here to just tell us how inspiring we are without actually doing anything about it because it doesn’t lead to anything. I know you are trying, but just not hard enough. Sorry.”

Greta Thunberg inspires climate activists everywhere: In pictures Show all 12 1 /12 Greta Thunberg inspires climate activists everywhere: In pictures Greta Thunberg inspires climate activists everywhere: In pictures In the protest that started a movement, Greta skips school to sit outside of the Swedish parliament in Stockholm in order to raise awareness of climate change on 28 August 2018 Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the World Economic Forum in Davos on 25 January AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta stages a protest at the World Economic Forum in Davos on 25 January Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the House of Commons in London on 23 April PA Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses to the occupation at Marble Arch in London on 21 April AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta meets the pope on a visit to Rome Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the senate in Rome on 18 April Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses a debate of the EU Environment, Public Health and Food Safety committee at the European Parliament in Strasbourg on 16 April AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta receives the Special Climate Protection Award at the German Film and Television awards in Berlin on 30 March AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta attends a children's climate protest in Berlin on 29 March AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses a children's climate protest on 1 March in Hamburg Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta attends a meeting for the Civil Society For rEUnaissance at the EU Charlemagne Building in Brussels on 21 February AFP/Getty

Thunberg emphasised that lawmakers should be looking to scientists for ways to best address the climate crisis.

To highlight this point, she sent congress the IPCC’s 2018 Special Report on Global Warming of 1.5C, with eight sentences of her own, rather than submit the personal statement customary at such testimonies.

“I am submitting this report as my testimony because I don’t want you to listen to me,” she wrote. ”I want you to listen to the scientists. And I want you to unite behind the science. And then I want you to take action.

Those lawmakers gathered at the packed testimony were among the most ardent supporters of climate action in congress, but they have struggled to pass meaningful legislation in a senate controlled by Republicans.

Perhaps surprised by the bluntness of Thunberg’s accusation that they were not doing enough to address the climate crisis, some politicians reportedly laughed while others applauded. Mr Markey vowed that those in attendance would ensure climate change was placed at the heart of US politics.

Greta Thunberg explains why she chose not to fly to US

“We hear you,” Mr Markey responded, vowing that lawmakers “will redouble our efforts to make sure that we inject this issue into the politics of this building and this country because time is running out.”

In addition to Thunberg, a number of youth activists from across the Americas were invited to address the task force in an attempt to build momentum for serious climate action in the run-up to a week of global climate strikes beginning on Friday.

There will be 4,638 events in 139 countries, Thunberg said. In New York City, children will not be penalised for skipping school, while in Australia, the government of Victoria has encouraged people to strike.