This has seen public concern skyrocket, and it's essential that this concern translates at the ballot box in December.
Tens of thousands of children across the UK have bunked off school on Friday as part of a global climate strike, campaigners said.
The international movement, Fridays For Future, which was started by teenage activist Greta Thunberg in 2018, encourages pupils to protest against governments' lack of action on climate change by not attending school on Fridays.
Around 120 demonstrations are being staged around the UK, as well as over 3,000 worldwide in 150 countries.
The protests come following a cross-party leaders' debate on climate change that was broadcast on Channel 4 on Thursday evening.
Activists say it is vital that the environment is pushed to the top of the political agenda.
Jake Woodier, campaigner with the UK Student Climate Network, said: "The idea is to make sure that there is enough pressure on the electorate and to highlight that this is not any ordinary election, it's a climate election.
"Over the past year young people have been taking to the streets on a monthly basis to highlight the urgent need for action on the climate crisis.
"This has seen public concern skyrocket, and it's essential that this concern translates at the ballot box in December.
"We've got incredibly limited time to address the climate crisis and the next government will be in charge for five vital years that we can't afford to lose."
Hundreds of young people gathered in Parliament Square in central London on Friday morning.
Among them was 12-year-old Niamh, who travelled from Guildford to attend the demonstration with her brother Finn, 10, and father Simon.
Speaking to the PA news agency, she said: "It's not fair. It's going to affect my generation who won't know what a polar bear is.
"If we're off school it will make a difference. I think the government is doing a bit but we're being idiots about it."
Simon, 43, added: "I think it's good to get them involved and be socially aware, to get involved to fix this for everyone. "If we don't, we're buggered."
Similar protests are taking place in other UK cities such as Cambridge, Bristol, Manchester, Newcastle, Glasgow and Aberdeen.
The UK Student Climate network says that although the majority of attendees are young people there are an increasing number of adults at Fridays For Future events.
Gwen, 48, from north London, said: "They [the kids] need to be empowered. They need to know they can make a difference. They need to know that they can change the world for the better."
Her son Tariq, 12, said: "We're here because we want democracy and [the Government] to give us a Citizens' Assembly and to end climate change.
"They are the ones with the power to give us what we want. His friend Tom, 13, added: "It's important stuff."
The young activists were joined at Westminster by other groups and chanted "where the **** is the government?"
When asked about the language used, Gwen said: "They're going to be exposed to it at some point - I'd rather it was at a protest march."
Activists in London plan to unfurl a 30-metre long banner with a "message to the electorate" on Westminster Bridge on Friday afternoon.
Greenpeace UK's chief scientist Dr Doug Parr said that youth demonstrators were the "moral conscience not just of their generation but the whole of our society".
"These young people are walking out of school to teach us a big lesson on what it means to be responsible adults," he said.
"Because there's no running away from a nature and climate emergency that's erupting all around us.
"Whoever's going to be the UK's next prime minister must realise the gravity of the situation and be willing to take the radical action needed to address it."
During the Channel 4 debate Labour leader Jeremy Corbyn, Liberal Democrat leader Jo Swinson, Scottish First Minister and SNP leader Nicola Sturgeon, Plaid Cymru's leader Adam Price and Green co-leader Sian Berry discussed their party's plans for climate action.
Prime Minister Boris Johnson and the Brexit Party's Nigel Farage declined to take part in the debate.
Their absence was represented by two circular ice sculptures engraved with maps of the world which stood melting on stage throughout the hour-long programme.
The Conservatives have complained to Ofcom about the sculpture.
Tory minister Michael Gove also posted a video on Twitter, saying he asked to take part in the debate but was refused.
Mr Gove, a former environment secretary, said that the snub was a "denial of debate" and that the other parties were "running scared of debating the Conservatives".
Mike Bedigan is a reporter for PA.