Much of the climate debate of the last few weeks has been characterized by a sense of growing consensus and agreement.

Charlotte Wolff-Bye, Statoil’s Head of Sustainability Strategy told us she was looking forward to the UN talks as a chance to listen and engage with others. Left-wing New York based magazine Jacobin advised its readers to put concerns with Climate Week’s Lockheed Martin sponsorship deal on hold, and still attend Sunday’s march. Scientists stood under banners declaring “the debate is over”.  Media coverage was full of  words like “chorus” “broad” “momentum” “joining” and “coalition”.

But as the People’s Climate March started to disperse near the Lincoln Tunnel, a local activist could be heard over a microphone advertising direct action the following day: “Today was all very friendly, but.”

The next morning, the consensus started to crack. “Flood Wall Street” activists met at 9am in Battery Park and, after a series of speeches and some non-violent direct action training, moved on to the nearby Financial District. Dressed in blue and carrying a 300 foot banner to represent rising seas and the “river” of people globally protesting, they blocked streets around the stock exchange for much of the day.

Further uptown, an event showcasing women on the frontlines of climate change held at the Church Center of the United Nations brought out some anger and disagreement within the highly patrolled areas of the UN (guns, uniforms, ID-checking and police dogs abound). The idea of 2°C warming as a safe limit was dismissed as still condemning too much of the world, and not nearly ambitious enough. Expressions of solidarity were made for the Wall Street protestors. Nobel Laureate Jody Williams ridiculed the so-called global leaders meeting at the summit: “They are not leading. We’ll kick their butt.”

Patricia Gualinga – Kichwa leader, Saryaku, Ecuador – received a large round of applause when she spoke of speaking back to those wanting to drill for oil: “They say you are poor and we’ll develop you. But you are poor, you are the ones who bring poverty. We are the ones with clean water and clean air.” Casey Camp-Horinek, of the Ponca Nation, then took the floor, and changed the tone dramatically. With a mischievous look she nodded to the pulpit at the back of the room, raised far above the audience and other speakers: “Can I speak from there?”. From her newly lofty position she cracked jokes about immigration laws and poked fun at “this fictitious thing called money” before expressing visible anger at the idea of carbon trading. In minutes, she’d totally shifted the power dynamics and emotional cadence of the room.

Back to Wall Street, where a polar bear and a couple of Captain Planets were being arrested. As the Guardian reported, the crowd’s relations with police were considerably less adversarial compared to those of Occupy Wall Street, but there were several reports of pepper-spraying late in the afternoon. Renewable energy campaigner and entrepreneur Jeremy Leggett tweeted from a Climate Week event that he was drinking fine wine, feeling sickened by the closed self-congratulation of his fellow delegates. Some of the divisions of New York City – and the climate debate it aims to encapsulate this week – felt a bit more obvious.

This is one of the reasons why “the debate is over” makes for a lousy climate change slogan. If this new momentum is anything, it is an opportunity to open up spaces for new, better debates than whether climate change is happening or not. Words like consensus, engagement, chorus, momentum and coalition have a way of glossing over marginalised voices. Disagreement can delay, but it can also help unearth previously under-acknowledged injustices and productively inspire new solutions.

There’s a growing sense that change is coming. How much of this change is – to paraphrase Sunday’s placards – climate change over system change is yet to be seen, as is who gets to set the terms of any new systems. Roadmaps are being written, and a range of people want to influence the route. The people at Flood Wall Street want a voice in this process as much as those with access to the various invite-only Climate Week events.

As the evening closed, the Empire State Building lit up green. A beacon of something, though what exactly is still unclear.