SCOTLAND yesterday set itself the goal of becoming the greenest nation in the UK, with a pledge to slash greenhouse gas emissions.

Ministers called on every household and business to play a part in reducing emissions equivalent to 2.7 million tonnes of carbon a year by 2010 compared to 2000.

Over the next four years, Scots will be pressed to cycle to work, use low-energy lightbulbs and buy more efficient cars in an effort to help achieve the goal.

Critics claim that Scotland's programme will do little to affect climate change globally - Scotland's greenhouse gas emissions comprise just 0.2 per cent of the world's total. But Ross Finnie, the environment minister, said Scotland's small size was no excuse for doing nothing.

Environmental groups were sceptical that significant progress would be made while the Executive continues to support air and road transport and has no power to choose methods of energy generation or punish carbon-emitting industries with taxes.

Launching the strategy yesterday, Mr Finnie said: "The commitment we are making today is a serious response to the threat that climate change poses to our communities, our environment and our economy.

"Climate change requires an urgent global response. Scotland may be a small country but size is not an excuse for inaction."

The Scottish commitment comes as Margaret Beckett, the Westminster environment minister, admitted the UK was likely to miss its self-imposed target of reducing emissions by 20 per cent between 1990 and 2010.

To play its fair share in cutting UK greenhouse gas emissions, the Scottish Executive needs to make savings equivalent to only 1.7 million tonnes of carbon a year between 2000 and 2010.

But Mr Finnie said a saving of

2.7 million tonnes could be achieved through policies already introduced since 2000 and through a number of new initiatives in renewables, transport, agriculture and waste management.

In addition, another 1.1 million tonnes could be saved in Scotland through environmental policies controlled by Westminster, such as the introduction of renewable energy.

Mr Finnie added: "It is something that has gone up the agenda in recent years, but we still have a long way to go for people to instinctively act in ways to reduce climate change. But we can do it."

In 2003 - the latest year for which figures are available, Scotland was responsible for producing 14.9 million tonnes of greenhouse gases. Bizarrely, because of the way the figures are calculated, the Executive can meet its savings target even if the quantity of greenhouse gas emissions increases.

Critics yesterday questioned the significance of the new programme. Dr Sonja Boehmer-Christiansen, reader in geography at the University of Hull, said the contribution of Scotland will have little effect on worldwide climate change.

Robin Harper, of the Green Party in Scotland, said the Executive was unlikely to meet the target while it continued with current policies such as building new motorways, expanding airports and removing tolls, that all contribute to climate change.

"Ministers are to congratulated for the language used, but it is bereft of significant policy initiatives other than to consult here and there and hardly touches on the key issues of traffic reduction, air travel and energy efficiency.

"Ministers may express a commitment to tackle climate change but the reality is that their policies are currently set on course to increase emissions, and fail to meet those targets," he said.

Richard Lochhead, the SNP environment spokesman, said the target was no good while the powers over energy generation are held by Westminster. "Only with the full powers over issues such as energy policy, industry regulation and taxation can we achieve our environmental goals," he said.

Figures out yesterday showed UK carbon emissions are, at 157.4 million tonnes, the highest since Labour came to power, 2.3 per cent more than in 1997 and only 4.8 per cent below emission levels in 1990.

Duncan McLaren, chief executive of Friends of the Earth Scotland, said: "The solutions to climate change already exist and millions of people across the country want action. Given his [Mr Blair's] continuing failure to do what is necessary, it is clear that a climate change law is needed to deliver the cuts in pollution that the scientific evidence demands." However, he backed Scotland's target.

Dr Richard Dixon, director of WWF Scotland, said Executive ministers were proposing "more positive action" than their UK counterparts.

"We welcome the introduction of a target, especially one that should ensure we deliver a fair contribution to the Kyoto agreement and indeed go beyond this, as we desperately need to," he said.

TRANSPORT A NATIONAL Transport Strategy will decide on climate change targets for the transport sector. Schemes include rewards to promote sustainable travel in each region through public transport and cycling networks.

For example, a tonne of carbon can be saved by driving a small, economical car rather than a large 4x4 vehicle in just over a year's average mileage.

BUILDING BUILDING standards will ensure new houses are built to be energy efficient, while upgrades on existing buildings can save on bills. Homeowners can find out about how to make savings at Energy Efficiency Advice Centres across Scotland. Basic measures include turning down the central heating thermostat, using energy- saving lightbulbs and not filling the kettle full for one cup of tea.

INDUSTRY THE climate change levy, which taxes business for carbon emissions, is set by Westminster. However, the UK Emissions Trading Schemes, which offers financial incentives for cutting emissions, is devolved.

The Scottish Energy Efficiency Strategy aims to promote renewables within businesses, while tourism will be expected to offer more sustainable packages for those visiting Scotland.

FORESTRY GROWING forests can reduce green house gases by sucking up . In 2000 is was estimated afforestation would contribute to removing 0.41 MtC by 2010. To increase forestation, the Executive introduced the Scottish Forestry Grants Scheme. The industry is also being driven by increased demand for wood for fuel and biomass, a more efficient way to keep warm, and timber for houses.