The message from the protesters is clear. Too little, too late and far too slow.
The marchers I spoke to at the Fridays For Future march - the school strike movement initiated by Thunberg and now famous around the world - were angry.
Deborah Halonen, a 29-year-old from on an exchange from Sweden, dismissed the COP announcements as "mostly just greenwashing".
The leaders are "not taking the [climate crisis] seriously... it would be nice if some countries even bothered to show up," she said.
Eilidh, Katie and Sive, all 17 years old, have been striking for a couple of years in Edinburgh and travelled in by train to join today's march.
"Nothing is changing," said Sive. "We get words and no action."
Leaders have left the conference because the World Leaders Summit part finished on Tuesday - but "nothing is more important than this," she said.
Isla is 11 and from Glasgow.
"We are angry," she said and is here because she wanted to "stand up".
"No one is doing anything for climate change," she says.
"In 30 years Glasgow is going to be flooded." These are her fears.
But she also said it was fun to "come here today and be with everyone" as she marched in the crowd at the front, everyone packed in mostly shoulder-to-shoulder, amid songs, chants and banners.
But it was also noticeably calm, as parents, strikers and supporters made their way from Kelvingrove park to George Square.
And it was creative. One of the march's anthems was: "What do we want? Climate justice! When do we want it? Now!"
But this one soon caught on, to the tune of "Hey Baby" by DJ Otzi.
"Heeeey, hey Boris. Oh ah. I wanna kno-oo-ow how you sleep at night."
The march took a long time to get going as there were so many members of the news media at the front, walking backwards with cameras focused on the group of speakers leading the way.
The group know how to get publicity - and indeed a crowd. At the end organisers claimed 20,000 people had turned up for it, though that number has not been confirmed by Police Scotland.
Organisers had formed a human "bubble", with people and blue rope around the speakers and activists from MAPA - Most Affected People and Areas.
"A better term for the global south" as one of the bubble-formers told me.
When the march arrived in George Square, the activists from around the world - including Uganda, Mexico, Papua New Guinea and the Philippines - took their turns to speak on stage.
Their message? Firstly, that indigenous people are the best guardians of their land.
"We the indigenous people are the main defenders of the environment," said a member from a group of indigenous protesters from Brazil and Ecuador.
Secondly, the promises made at COP26 are not genuine, or not enough. Mostly the former.
An activist from Pakistan delivered a litany of accusations against predominantly white western countries for plundering lands for fossil fuels.
"We are here because we know that COP26 won't do anything," said a protester from Namibia.
Greta Thunberg, who spoke last after almost two hours of speeches, told the crowd that COP26 was a "greenwash festival" full of "empty promises".
"A two-week-long celebration of business as usual and blah blah blah," she said.
Whatever has been achieved in the conference halls and negotiating rooms so far either isn't getting through to these protestors or isn't enough. Or perhaps it's both.
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