The Extinction Rebellion movement kicked off a week of marches, demonstrations, and peaceful civil disobedience across the U.S. and around the world on Monday to demand "systemic changes to stop global warming while there's still time left."

"Those who are most vulnerable and least responsible for this crisis are the ones who are suffering the most. People are dying. Species are disappearing. Everything is at stake."

—Bea Ruiz, Extinction Rebellion U.S.

In Scotland, climate campaigners plan to shut down Edinburgh's North Bridge to get their government's attention. Similar disruptions are planned in dozens of cities across the U.S. and the United Kingdom.

According to Extinction Rebellion—which several climate activists in the U.K. launched last year—tens of thousands are expected to take to the streets in nearly 40 countries across six continents.

As the Guardian reported Sunday, American activists "hope the arrival of Extinction Rebellion will be a watershed moment for the U.S. environmental movement, shifting it from what they see as a tepid response to the cavalcade of disasters threatening the livability of the planet."

View a map of Extinction Rebellion regional groups to find an event near you.

"Governments have failed us," Bea Ruiz, national coordinator for Extinction Rebellion U.S., said in a statement. "Those who are most vulnerable and least responsible for this crisis are the ones who are suffering the most. People are dying. Species are disappearing. Everything is at stake."

"It's time to do what's never been done before in the fight against climate change—a collective and coordinated international rebellion that will continue to escalate until our demands are met," Ruiz added.

The international movement issued a set of straightforward demands to political leaders around the world: Declare "a climate and ecological emergency" and act immediately to "halt biodiversity loss and reduce greenhouse gas emissions to net zero by 2025."

"It's time to declare a climate and ecological emergency," Miriam Robinson of Extinction Rebellion Melbourne said in a statement. "We are in the midst of the sixth mass extinction, but the government has been pouring billions of dollars into fossil fuel infrastructure—more gas hubs, ports, coal mines and roads, while sadly neglecting and degrading the natural world."

Petitions, phone calls, and letters to government officials are no longer sufficient to confront the scale of the global climate crisis, Extinction Rebellion organizers said. Only civil disobedience on a massive scale, they argued, can force governments to act.

"Governments prioritize the short-term interests of the economic elites, so to get their attention, we have to disrupt the economy. They have left us with no other option," organizers said in a statement. "This moment demands action that is proportionate to the threat we face."