“We have two weeks to set Congress’s agenda for 2019. I’m writing to ask that you join me in doing something big to help change history.”

That’s how I announced our vision, on November 28, calling for a 500-person action on December 10 in Washington, D.C., to call on Democratic leaders to back Representative-elect Alexandria Ocasio-Cortez’s (D-NY) select committee on a Green New Deal before Congress closed for the holidays.

A Green New Deal is an umbrella term for a set of policies and programs to help stop the climate crisis, fight poverty, and improve the lives of millions of working Americans. It includes bold action like massive investment in communities on the frontlines of poverty and pollution (which often go hand in hand), a jobs program where the federal government would guarantee a good job to anyone who wants to get to work transforming our economy, and a complete overhaul of major industries in the country to end our nation’s dependence on fossil fuels and ensure a livable future for our generation.

It’s more clear than ever how urgent it is that we combat this crisis: Two months ago, the United Nations Intergovernmental Panel on Climate Change (IPCC) released a ground-breaking report that warns that we as a global society have 12 years to transform our economies and politics and a much shorter timeline to decarbonize all sectors of the economy or risk climate catastrophe. That would mean stronger storms and more-devastating wildfires and droughts and would jeopardize the food supply of more than a billion people.

Now is the moment. Sunrise Movement, which I helped found with seven other young people in 2017, is building an army to stop the climate crisis and create millions of good jobs for our generation in the process. We’re working to build the people power and the political consensus for the real solutions to climate change, like a Green New Deal.

Young people are increasingly joining the movement for climate justice and are on fire about a Green New Deal. Why? Because this is perhaps the first time in our country’s history that a document lays out a comprehensive plan for what it will take to protect human civilization and our planet from the ravages of climate change and to transition our country off fossil fuels. It sounds hyperbolic, but life as we know it is at stake. We need politicians to stand up to the fossil-fuel billionaires who bankroll Congress and rally behind a Green New Deal now.

But, I’ll be honest — on November 28, as I was announcing an action 12 days away, I was terrified we wouldn’t be able to make it happen. This would be the biggest one we’d ever tried to put on, more than twice the size of our action at Representative Nancy Pelosi’s (D-CA) office a few weeks prior, when Representative-elect Ocasio-Cortez — one of the youngest and most popular new lawmakers elected in the midterms — joined us to call for a select committee on a Green New Deal. The next time around, we had just 12 days to get everyone to D.C., and on a school day no less.

But at 8 a.m. that Monday morning, I found myself speaking to the more than 1,000 young people who showed up in our nation’s capital to hold a sit-in at the offices of Democratic leaders. They came to put pressure on the lawmakers who have the power to make the select committee on a Green New Deal a reality, and who we are calling on to have the courage to stand up to the fossil-fuel billionaires who bankroll Congress and take action on climate change in line with what science demands. Young people came from across the country, including a bus full of high schoolers who skipped school and drove 12 hours from Kentucky. There were vans from Florida, Michigan, and Maine. Nearly 150 people were arrested in what was one of the biggest youth-led actions at the Capitol in recent memory. In the 36 hours following the protest, 13 additional representatives backed the select committee, all of whom we’d met with on Monday.