- Video report by ITV News Science Editor Tom Clarke
I’ve reported on quite a few of these UN Climate summits.
They tend to move at what feels like a glacial pace - ironic given that in the 20 years the talks have been happening, the world’s real glaciers have only speeded their melting into the sea.
But on Tuesday, at the COP25 meeting in Madrid I witnessed something completely new.
A huge queue of people barging and arguing trying to get into a talk being held by climate scientists.
Among those speaking at the conference was Licypriya Kangujam, she’s and eight-year-old from New Delhi who spoke on Tuesday at a session alongside John Kerry.
She told ITV News: "This is the time to do action."
"What I want is not today or tomorrow but what needs to be done now."
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Kangujam was joined by other activists from around the world, namely Xiye Bastida from New York and Daisy Jeffrey from Sydney.
Shortly after meeting climate champion Al Gore, Batida spoke to ITV News about what a huge impression he has made on her life.
Her fellow delegate from Sydney then spoke about the need for action to tackle climate change, instead of just words.
Usually, events like that are only attended by a few specialist journalists like me.
But this meeting was different: it had been convened by Greta Thunberg, now the undisputed figurehead of the global youth movement to halt climate change.
Since her Youth Strike for Climate Action started last summer, Greta Thunberg has repeated the same message of uniting behind the science of climate change.
But the view at the summit here is that that’s still not happening.
The science makes it pretty clear that emissions of greenhouse gasses need to be more or less halved within a decade to prevent global warming exceeding 2C.
They then need to fall to zero by 2050 or so.
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But there’s nothing happening at this meeting in Madrid to suggest the more than 190 signatories to the Paris Agreement are anywhere close to that level of ambition.
In fact, current pledges put the world on course for more than 3C of warming.
Also, countries here are still negotiating line by line detail of how to implement certain tricky parts of the Paris Agreement which was signed four years ago.
Many of the youth climate strikers have green stripes painted under their eyes - to tell the leaders meeting here they are watching them.
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But will that be enough to deliver the change that’s needed?
Some tell me if the negotiations were up to them, they’d have the problem solved in a year or two.
But as Greta Thunberg pointed out on Tuesday: “We can’t wait for the children of today to grow up and be in charge so we also need to educate the people in charge today.”