Democrat presidential candidates on Monday lauded Swedish climate change activist Greta Thunberg’s scathing speech targeting world leaders for what she described as their inaction against ecological self-extermination.

In a tweet, Sen. Bernie Sanders (I-VT) wrote it was a “disgrace” that a teenager had to speak out against purported global warming.

“What a disgrace that it takes a 16-year-old to tell world leaders what they won’t acknowledge: We cannot continue with this type of ruthless capitalism that is destroying our planet. This is why we need young people leading our climate justice movement,” he said, sharing a video snippet of the 16-year-old’s remarks.

What a disgrace that it takes a 16-year-old to tell world leaders what they won't acknowledge: We cannot continue with this type of ruthless capitalism that is destroying our planet. This is why we need young people leading our climate justice movement. pic.twitter.com/uKpMUc2CMw — Bernie Sanders (@SenSanders) September 23, 2019

“We need to do better—for Greta, for the students marching for our lives, and for all of the young people who will inherit our planet from us in worse shape than we found it, unless we act,” tweeted former Rep. Robert Francis “Beto” O’Rourke (D-TX).

We need to do better—for Greta, for the students marching for our lives, and for all of the young people who will inherit our planet from us in worse shape than we found it, unless we act. https://t.co/3z8gAtscea — Beto O'Rourke (@BetoORourke) September 23, 2019

Sen. Kamala Harris (D-CA) also praised Thunberg’s harsh criticisms, tweeting that “we are currently failing our nation’s youth.”

.@GretaThunberg is right: we are currently failing our nation’s youth by not taking swift action to combat the climate crisis,” Harris tweeted. “We owe it to them to stand up to polluters and stop poisoning our planet,” wrote Harris, who also shared a clip of the climate alarmist’s speech.

.@GretaThunberg is right: we are currently failing our nation's youth by not taking swift action to combat the climate crisis. We owe it to them to stand up to polluters and stop poisoning our planet.pic.twitter.com/coGN5JQOmA — Kamala Harris (@KamalaHarris) September 23, 2019

Thunberg, who has become the de facto leader of the youth climate movement, addressed attendees of Monday’s Climate Action Summit at U.N. headquarters.

“You are failing us,” Thunberg told the politicians and policymakers assembled at U.N. headquarters. “But the young people are starting to understand your betrayal. The eyes of all future generations are upon you. And if you choose to fail us I say we will never forgive you. We will not let you get away with this. Right here, right now is where we draw the line. The world is waking up. And change is coming, whether you like it or not.”

Later Monday, Thunberg and 15 other children filed a lawsuit against five countries over the climate change crisis.

According to the suit, Germany, France, Brazil, Argentina, and Turkey have violated the activists’ rights as children. The five named countries are parties to the Convention on the Rights of the Child, a treaty signed by dozens of nations 30 years ago.

The UPI contributed to this report.