Greta Thunberg tells climate march: 'I will not be silent while the world is on fire – will you?'
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Thunberg, 17, told the crowd, estimated at 30,000 by organisers: "This emergency is being completely ignored by the politicians, the media and those in power.
"Basically, nothing is being done to halt this crisis despite all the beautiful words and promises from our elected officials.
"So what did you do during this crucial time? I will not be silenced when the world is on fire."
Thunberg continued: "They are behaving like children so it falls on us to be the adults in the room.
"Once again, they sweep their mess under the rug for us - young people, their children - to clean up for them.
"But we must continue and we have to be patient. Remember that the changes required will not happen overnight since the politics and solutions needs are far from sight."
Thunberg was joined on a march around Bristol by thousands of people carrying placards.
She walked at the front of the crowds in the rain, behind a green banner reading Skolstrejk for Klimatet, which translates from Swedish as School Strike for Climate.
Protesters of all ages waved flags, placards and banners and chanted as they made their way around the city centre.