The People’s Climate March (PCM) was a large-scale activist event to advocate global action against climate change, which took place on Sunday, September 21, 2014, in New York City. With an estimated 311,000 participants, it was the largest climate change march in history. Described as “an invitation to change everything,” the march was called in May 2014 by 350.org, the environmental organization founded by writer/activist Bill McKibben, and it was endorsed by “over 1,500 organizations, including many international and national unions, churches, schools and community and environmental justice organizations.” It was conceived as a response to (but not a protest against) the scheduled U.N. Climate Summit of world leaders to take place in New York City two days later, on September 23.

Although based in New York, the event was intended to be global in scope and implication, and there were “companion demonstrations” worldwide. Organizers intended the march to be “the largest single event on climate that has been organized to date… one so large and diverse that it cannot be ignored.” The entire PCM project consisted of “numerous events, actions, symposia, presentations, and more organized over the course of the days leading up to the Summit, and in the days following,” of which the march was intended to be “the anchor event.”

The UN climate summit in Paris this December will be the biggest global climate summit this decade. The national and global stages work in tandem, either dragging each other upward in ambition, or spiralling downward. We must make Paris a moment to seize and build on the momentum. A powerful way to do that would be for the entire world, for the first time, to agree to the goal of a decarbonised global economy powered by clean energy. That would send an immediate signal to clean and dirty energy investors everywhere, accelerating the energy transition that is already underway.

Hope is growing, momentum is with us, but we’ve been here before. From the Earth Summit in 1992 to the Kyoto Protocol in 1997, the world has surged forward in the past, only to be knocked back by the toxic politics of the fossil fuel lobby with its junk science and well-funded climate denialism. Each time, the gap between the action we’re taking and the action our survival requires widens. We need a movement that is built to last, built to win and keep winning, over decades to come.