Young people must be prepared to continue striking to call for action on climate change for a long time and not back down, Swedish climate activist Greta Thunberg told a climate strike rally in Denver on Friday.

Thunberg said she and fellow youth activists won't beg those in power to act because she expects leaders to keep ignoring them.

“We will instead tell them, if they won’t do it, we will,” the 16-year-old said to loud cheers.

“The world is waking up and we are the change. The change is coming whether you like it or not.”

Thunberg spoke for less than 10 minutes to a crowd of several thousand at Civic Center Park near the state Capitol.

The rally highlighted Colorado activists, like Madhvi Chittoor, 8, who has campaigned in the state against plastics. Thunberg again scolded leaders for not doing enough to fight climate change and for ignoring science.

Echoing a line from an angry speech at the UN last month that drew global attention, she said several times of leaders, “How dare they,” with some in the crowd repeating the line.

Thunberg began holding solitary demonstrations outside Sweden’s parliament in August 2018, skipping classes once a week to protest climate change. Her “Fridays for Future” demonstrations have inspired millions across the world.