MSPs have agreed a target of a 42% cut in emissions
Landmark legislation to help Scotland tackle the threat of climate change has been passed unanimously by MSPs.
Ministers have set a target for a 42% cut in greenhouse gas emissions by 2020, rising to 80% by 2050.
The SNP has claimed its climate change plan was more ambitious than Westminster proposals.
As well as meeting targets, ministers said other action was vital, such as boosting renewable energy and a leap in energy efficiency.
The Scottish Government's Climate Change Bill cleared its final parliamentary hurdle, after ministers upped their 2020 target from 34%.
The climate change issue affects all of the peoples of our planet
John Swinney Scottish finance secretary
But it will only be set at 42% if European governments agree to reduce emissions by 30%.
SNP ministers acknowledge an 80% cut in emissions in itself would make no difference on a global scale.
But they hope Scotland can take a lead on the issue - one of the most serious threats facing the planet - for others to follow.
The Scottish Government has set out a wide-ranging vision to address climate change, including a drive to boost renewable energy such as wind and wave power.
Ministers also want to see significant progress in boosting the energy efficiency of buildings, an increase in the number of electric vehicles on the roads and cuts in emissions across the farming and rural sector.
Finance Secretary John Swinney told MSPs that passing the "world-leading" legislation was a historic day for the Scottish Parliament.
"The climate change issue affects all of the peoples of our planet," he said.
"However large or small our relevant contributions are in terms of emissions we have a duty to make a contribution to that process at this stage."
Lib Dem and Green Party attempts to strengthen the bill by setting annual targets for emissions cuts between 3% and 4.5% were rejected by MSPs.
And a Green Party attempt to include a 90% target for 2050 - instead of 80% - was overwhelmingly rejected.
Green co-leader Patrick Harvie said: "If we are going to include specific targets in this bill, they should be the right targets, not the wrong targets.
The move drew praise from California Governor Arnold Schwarzenegger
"Those who have studied the subject in detail understand now that 80% is a target which is already out of date."
However, the party was successful in strengthening the bill's provisions to include greenhouse gases emitted by planes and ships in the pollution-reduction targets.
Labour environment spokeswoman Sarah Boyack warned the government must not back down on targets, adding: "Our challenge is not passing this bill, it is implementing it."
The Liberal Democrats' Alison McInnes said: "Disappointingly, the 2020 goal of 42% has strings attached to allow government to tamper with the target."
Alex Johnstone, the Tory MSP, told parliament: "This is indeed a great day."
"When I come across people who might instinctively be supporters of my party who have grave doubts about the nature of climate change or the requirement to deal with climate change, the position I have taken has allowed me to argue the case for this bill," he said.
Hollywood star and Governor of California Arnold Schwarzenegger endorsed the move by the Scottish Parliament.
He said: "Scotland's ambitious and comprehensive targets encourage other nations to step up to the plate as we look toward an international agreement in Copenhagen, and it sends a message to the world that we must act now and we must act swiftly."
International talks on climate change are due to take place in Copenhagen in December.
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