Activists gathered for a town centre Climate Strike protest.
Some 50 joined the demonstration in King's Lynn's High Street today.
They included school children - some of whom had been given the day off to attend.
Margaret Purves, 11, from Watlington, said: "I'm here because I care about saving all the animals and I don't want plastic to kill them all."
Her mother Maria said: "The school was very supportive. She goes to a school in Cambridge and they gave her the day off."
Springwood High School pupil Thomas Archer, 12, said: "It's our future and if the adult politicians aren't going to do anything about our future we're going to have to do it."
The protest was also attended by staff from nearby RSPB reserves at Titchwell and Snettisham.
Public affairs manager Steve Rowland said: "The RSPB is supporting it because climate change is the biggest threat to the natural environment we face."
Campaigners hoped to bring presssure to bear on West Norfolk council to declare a climate change emergency.
They say the borough has the highest emissions of any area of Norfolk, while Lynn and the low-lying Fens are vulnerable to rising sea levels and tidal surges.
Ian Devereux, cabinet member for environment at the borough council, said: "Climate change has recently been raised at full council meetings and there is an agreement to consider the impact of climate change within west Norfolk.
"We are currently establishing the baseline carbon footprint of the borough council alongside the footprint for the whole of the west Norfolk area. This will be followed up with developing and adopting a strategy, and targets, for climate change mitigation and potentially carbon offsetting.
"There are many examples of council activities that contribute towards climate change mitigation, next week I will be signing the Courtauld agreement which aims to reduce food and drink waste, as well as reduce greenhouse gas emissions and a reduction of water use in the supply chain."
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