Protesters from Extinction Rebellion have told talkRADIO they are rallying today because they are “scared” and feel they have “no other option”.
Thousands of demonstrators from around the country gathered at Westminster to call on the government to “act now” on climate change.
A total of 135 people have already been arrested at the London protests so far.
The two-week-long action - taking place internationally - is set to be five times the scale of the London demonstrations in April, which saw 1,100 arrested.
Twenty-two-year-old George, a first-time Extinction Rebellion protester, told talkRADIO: “I’m scared, everything’s messed up and I don’t know what else to do.
“There’s no sense of recognition that everything’s messed up.”
It is George's first demonstration with Extinction Rebellion
Another demonstrator, who wished to remain anonymous, said “our lives are on the line”.
“Why should I care about a pension, why should I care about a mortgage if the generation above us, who have really done very well, aren’t taking action to make sure that we inherit a world that’s liveable?".
He added: “We’ve tried everything else, we’ve tried politics, the Green Party, we’ve tried campaigns like Greenpeace, Friends of the Earth, none of it has worked. We feel like there’s no other option so this is why we’re here doing this now - for our future. I’m scared. I want to live.”
Bridges and roads were blocked in central London as demonstrators cried for action.
Asked whether the government were listening to the protesters, 24-year-old Emma said: “They like to pay it lip service and say that they are but then the actions don’t quite align with what they’re actually saying."
Emma said she would 'fight for every single person on the planet'
She continued: “They are listening but they’re not taking direct action and that is what’s needed at this time.”
And fellow demonstrator Kate, from Land’s End, said this round of protests was "more important" than the ones that took place in April.
“I was here in April, there’s a very different atmosphere - this feels much more anxiety-making and more important because change isn’t happening," she said.