Green MSPs have said they will not back climate change legislation going through Holyrood unless ministers set tougher targets for curbing greenhouse gases.
The Climate Change (Emissions Reductions Targets) (Scotland) Bill faces a key vote in the Scottish Parliament on Wednesday.
Scottish Greens climate spokesman Mark Ruskell confirmed he and the party’s five other MSPs would not support it, unless ministers make changes.
The Bill sets the goal of “net-zero” greenhouse gas emissions by 2045 and a 90% reduction by 2040.
It is facing its final vote at Holyrood, days after thousands of young Scots marched in Edinburgh and Glasgow, demanding more action to tackle climate change.
The protests were part of a global day of action, inspired by activist Greta Thunberg after a series of school strikes last year.
Scottish Greens want the Holyrood legislation toughened up to include a target of an 80% reduction in emissions by 2030 – with organisations including Stop Climate Chaos and Friends of the Earth Scotland backing the call.
Mr Ruskell said: “Climate scientists have been clear that we have just a decade to turn this around.
“Championing eye-catching targets that won’t bite for decades while continuing to spend millions on new motorways and back maximum extraction of fossil fuels just won’t cut it anymore.
“The most important part of this Bill is the 2030 target because it will have a direct impact on what we do now, and because scientific evidence tells us the next 10 years are absolutely crucial.”
He added: “Talk of ‘world-leading targets’ is cheap. If Scotland is to lead it needs to be bolder.
“Look at Finland, which has pledged to be completely carbon neutral by 2035. That’s what happens when Greens are in government.
“Unless the SNP listens to young people and climate scientists and uses this Bill to provoke transformative action now by adopting an 80% target by 2030, Scottish Greens cannot in all good conscience back the Climate Bill.”