WATCH: Greta Thunberg says leaders' legacy is at stake if they keep 'ignoring the climate crisis'

Swedish teen climate activist Greta Thunberg addressed the US House of Representatives on Thursday, telling legislators that if they don't work to reduce emissions and lower the global temperature they will not be remembered well by their children. This was part of Biden's two-day Earth Day summit.

Thunberg said that history would hold the leaders accountable, and that it would be her generation of historians who will decide how to frame the legacy of these leaders and their contributions to the "climate crisis."

"Do this," she said, "or you're going to start having to explain to your children and the most affected people why you're surrendering on the 1.5-degree target. Given up—without even trying."

"Well, what I'm here to say, is unlike you, my generation will not give up without a fight. And to be honest, I don't believe for a second that you will actually do this. The climate crisis doesn't exist in the public debate today. And since it doesn't exist and the general level of awareness is so absurdly low, you will still get away with continuing to contribute to the destruction of present and future living conditions.

"And I know I'm not the one who is supposed to ask questions here, but there is something I really do wonder: How long do you honestly believe that people in power like you will get away with it?

"How long do you think you can continue to ignore the climate crisis, the global aspect of equity and historic emissions without being held accountable?" She asked.

"You get away with it now, but sooner or later people are going to realize what you have been doing all of this time, that's inevitable. You still have time to do the right thing and to save your legacies. But that window of time is not going to last for long. What happens then?

"We, the young people, are the ones who are going to write about you in the history books. We are the ones who get to decide how you will be remembered. So my advice to you is to choose wisely," she concluded.

President Joe Biden ran his presidential campaign on the premise that there are three major crises facing the American nation: the climate crisis, the racism crisis, the economy, and the coronavirus crisis. The climate has been Biden's favorite crisis, however, because of the leeway it gives his administration to enact broad, sweeping changes to every sector of the economy and society.

As part of his plans to tackle the climate crisis, Biden has jumped aboard the progressive plans for a Green New Deal, meaning that vast sums of government funding will go to create and enhance industries in sustainable energy sectors while moving the economy away from fossil fuels.

Thunberg has been an activist for climate change since she was 15. She skipped school to protest the lack of global leadership on climate change, and traveled to the US by boat to protest air travel.

Biden has pledged to cut US greenhouse gas emissions by 2030.