Voting blunder: Jamie McGrigor and Margaret Mitchell
A Climate Change Bill was defeated in Holyrood on Thursday after two Conservative MSPs pushed the wrong button.
Margaret Mitchell and Jamie McGrigor pressed "no" instead of "yes" for the Bill which would have seen a 0% reduction in emissions this year, followed by cuts of 0.5% in 2011 and 1% in 2012.
But due to the blunder the MSPs voted 64 to 62 against the proposed cuts and the Bill was narrowly defeated.
According to Conservative sources the Highlands and Islands MSP Mr McGrigor and Central Scotland member Ms Mitchell voted against the Tory whip by "mistake".
Labour, the Liberal Democrats and the Greens had combined to defeat the SNP administration.
After the defeat Climate Change Minister Stewart Stevenson pledged that a body would be set up to look at the issue.
Mr Stevenson told Holyrood the Scottish Government would establish a short-life working group, before bringing forward a new order setting out what the year-on-year reductions should be "in due course".
But Green MSP Patrick Harvie said the result of the vote meant there were now "serious questions" about Mr Stevenson's future as Climate Change Minister.
In its 2007 election manifesto the SNP had promised annual 3% cuts in emissions.
After the vote Labour environment spokeswoman Sarah Boyack said: "Instead of getting 3% annual targets when the SNP Government finishes its fourth year in office, it will have only put in place a reduction of 0.05%."
She added afterwards: "The SNP's efforts to cut carbon emissions have been a dismal flop. They didn't get support because they failed to set their sights high enough.
"Setting a 0.5% target next year is embarrassingly unambitious and their concession of increasing the target in two years' time from 0.5% to 1% is a one-off which will not be enough to make a substantial difference.
"At this rate the SNP will have made no progress on cutting carbon before the elections next year. The time for warm words is over, we need action."
After the vote the Scottish Government spokeswoman said the result of the vote was "disappointing given the Government has gone the extra mile in setting the standard for emissions reductions internationally as well as going above and beyond the recommendations of the UK expert Committee on Climate Change".
She added: "Early and sustained cuts in emissions are essential if Scotland is to meet its world-leading target of a 42% reduction by 2020.
"This Government has shown the leadership demanded to create this target and it would undermine the credibility of the Climate Change Act if we were to set ambitious climate change targets in the next few years which cannot be met."
She added: "We intend to engage with other parties through a short-life working group and will reintroduce the annual targets order to Parliament. We will then be able to begin the pressing challenge of setting an example to the rest of the world and delivering results."
