Labour is forcing a vote in parliament to declare an environmental and climate emergency, following mass protests over political inaction.
It could see the UK could become the first in the world to declare a climate emergency when MPs vote on the issue on Wednesday.
The move was one of the key demands of the Extinction Rebellion (XR) movement, which held demonstrations and paralysed travel routes across London in recent weeks.
Labour leader Jeremy Corbyn praised "the inspiring climate activism we've seen in recent weeks" and said it was a "massive and necessary wake-up call for rapid and dramatic action".
He also said he hoped other countries would follow suit in declaring an emergency.
Teenage climate activist Greta Thunberg, who has been nominated for a Nobel peace prize for her campaign to tackle climate change, welcomed the move and said she was "hopeful".
She said: "It is a great first step because it sends a clear signal that we are in a crisis and that the ongoing climate and ecological crises must be our first priority.
"We cannot solve an emergency without treating it like an emergency."
The 16-year-old had backed the XR protests, which saw key parts of central London occupied by activists and Mr Corbyn's home targeted.
Speaking about the upcoming vote, Mr Corbyn said: "For young people, the climate emergency is the cause of their generation. And we in older generations must face up to this seriously.
"We have to have a much more focused and serious approach towards climate change and the damage we're doing to our planet.
"We want a world for those in countries worst affected by and least to blame for climate change and our young people."
Labour's policy is for the UK to achieve net zero emissions before 2050 - far later than Extinction Rebellion's call for a 2025 deadline.
The opposition party said official figures which showed a 2% reduction in emissions last year suggested that net zero emissions could not be achieved until 2100.
It will use a motion to push parliament to urgently act to avoid more than 1.5C (34.7F) of global warming, which would require worldwide emissions to fall by about 45% from 2010 levels by 2030.