THE SCOTTISH Executive deliberately fixed an unambitious target for cutting climate-wrecking pollution so that it would be easy to meet and the success would make a "good news story".

Internal documents obtained by the Sunday Herald reveal officials advised the previous administration to play safe by aiming low. The revelation has prompted environmentalists to attack the climate target as "an accountant's trick". Officials, however, have defended the target as "realistic and ambitious".

Liberal Democrat and Labour ministers announced in March last year that Scotland would aim to cut carbon emissions by one million tonnes more than the "Scottish Share" of UK emissions by 2010. The Scottish Share, they said, was calculated to be 1.7 million tonnes of carbon savings in 2010.

But documents released under freedom of information legislation betray the thinking behind those figures. A memo from January 2006 says the target should be "a benchmark to measure success", not one "to indicate ambition" to people inside and outside the Executive.

"The Scottish Share gives us a solid theoretical foundation and we know we can set a target that exceeds this level, meet it and therefore have a good news story," wrote an official from the Department of Environment and Rural Affairs. "If we set a more ambitious target (either at national or sectoral level) we risk turning a good news story into a bad one."

An internal Executive study from 2005 showed that devolved policies would save 1.33 million tonnes of carbon by 2010. This is double a Scottish Share of 0.68 million tonnes, based simply on Scotland's relative population, and significantly higher than a Scottish Share of 0.94 million tonnes based on a more sophisticated sector analysis.

"The main finding is that, regardless of the method used, the available data indicates that Scottish carbon savings from devolved policies are greater than that required to deliver a proportional share," another official told colleagues in an email. "It certainly looks very positive!" responded one.

Dr Richard Dixon, the director of WWF Scotland, accused officials of trying to cover up the limitations of the Scottish Share. "These internal papers reveal the timidity with which the last Executive approached the subject of setting a climate target," he said.

Dixon also criticised the Executive for a prolonged delay in publishing projections of greenhouse gas emissions, originally scheduled for two years ago.

The absence of projections made it impossible to judge how hard it would be for the new SNP government to meet its "excellent" target, he said. The SNP has said it wants to cut greenhouse gas emissions by an average of 3% a year.

The Green MSP Patrick Harvie said: "The Scottish Share has always looked like an accountant's trick. It only measures the effect of positive policies and ignores negative policies like road-building and airport expansion. The previous Executive was always more concerned with image than action."

But he added: "With road-building and airport expansion still on the agenda, the priorities of the new Executive remain to be seen."

According to the Executive, the "Scottish Share" quantified the emission reductions that Scotland needed to achieve to make an equitable contribution to UK efforts to fulfil international obligations.

A spokeswoman said: "The share and target was a novel approach, developed after careful analysis and consultation using the best mix of data and policy options available at the time to produce a realistic and ambitious target."