Scotland can become a world leader in tackling climate change, ministers claimed yesterday as they launched the consultation on which they will base a bill in September.

However, it would be "foolhardy" to believe that every wind farm plan would meet with government approval, Finance Secretary John Swinney warned.

And, although environmentalists and opposition politicians backed the broad thrust of the bill, widespread concern remained about the detail, in terms of transport policy and the setting of regular targets on carbon emissions.

Mr Swinney predicted that the Scottish Government's decision to set a target of 80% reductions by 2050 would be followed by Westminster. "Watch this space," he said.

"The bill charts the course, not for the next six months or the next 12 months, it charts the course for the next 40 years. Scotland, in every component of our economy - individuals, business, government, public sector and the private sector - drawn together to focus on how we can reduce carbon emissions and make our contribution towards tackling climate change.

"It is a hugely ambitious agenda, one that the government is determined to pursue in the course of the period that lies ahead and one in which we want to engage the whole of Scotland," he said.

But environmentalists and opposition parties said the bill would have to include regular targets as well as a specific commitment for an interim goal in 2020.

The Stop Climate Chaos Scotland umbrella group gave broad backing to the consultation document yesterday.

Mike Robinson, of that coalition, said: "In order to meet overall targets it is essential that there is a commitment to annual reductions of at least 3% per year in statute. Without it, this is a departure from the SNP manifesto commitment.

"We will also be disappointed if the Scottish Government rules out the inclusion of emissions from international aviation in its targets."

Green MSP Patrick Harvie also welcomed the bill as a good first step, but said there had to be clear legal duties for ministers, the right long-term targets and the policies in place to achieve them.

"This won't just mean tinkering with policy in transport, energy, housing and agriculture. It will mean nothing less than the transformation of our economy, our society and our politics," he said.

Labour and the Liberal Democrats also gave a qualified welcome to the document but said aspirations had to be matched by action.

Mr Swinney refused to discuss the specifics of the controversial 181-turbine wind farm project in the Western Isles which is believed to be in the balance, but did say: "We have approved the second largest wind farm in Scotland in the course of our limited period in office "It would be foolhardy to believe that every single wind farm that comes forward for approval is going to get approval because not all will be in suitable locations.