Should people who work in industries with a low environmental impact be regarded as having green jobs? If so, a significant proportion of all our existing jobs - particularly those in health, education and community services - are green.

But what about jobs in industries that have reduced their ecological footprint, even though it remains substantial? Are these jobs more green or less green than jobs in industries whose footprint has always been small?

As a general rule, industries that are capital-intensive are likely to have a bigger footprint than industries that are labour-intensive, such as service industries. Does this mean we could make the economy greener by abandoning our age-old quest to use machines to replace workers wherever possible?

Do workers whose job is to return a mine site to nature after it has been worked out qualify as green-collar workers? If so, what about workers who clean up after oil spills?

And what about jobs that make the natural environment more accessible to people? If, for instance, you employ some young people to improve the signs on a bush-walking track (for which I'm always grateful) are these green jobs? The advocates of such projects seem to think so.

Visiting the great outdoors may make people more environmentally conscious. But what if the greater accessibility attracts more people and thus adds to the degradation of the area? Would the green jobs then turn brown?

If I were to drive all around the state - or fly all around the world - educating people about the damage the use of fossil fuels does to the climate, would that make me a green-collar worker?

Give up? I reckon it's virtually impossible to come up with a watertight definition of green jobs. But I don't think that matters. As the Australia Institute's report argues, focusing on green jobs is at best a distraction and at worse a snare and a delusion. The object of the climate change exercise is to move to an economy where little of our energy needs are met by burning fossil fuels, thereby making us a ''low-carbon economy'' and greatly reducing our emissions of greenhouse gases.

Focus on that and the jobs will look after themselves. What seems to be missing from the preoccupation with green jobs is an understanding that all economic activity creates jobs. Moving to a low-carbon economy may well involve reducing jobs in industries that produce fossil fuels, but it will also create them in renewable-energy industries. And even should producing a quantity of energy from solar, wind or whatever involve fewer jobs than producing the same quantity from coal, that's not a problem either. This greater productivity of labour would leave income to be spent elsewhere in the economy - probably the services sector - where it would create jobs.

Our businesses have been using ''labour-saving equipment'' to replace workers for 200 years and it hasn't cause mass unemployment yet. (It's true, however, that the workers displaced from fossil-fuel industries may not be well placed to take the jobs created in the renewable industries or elsewhere, but that problem - which does need to be dealt with - is common to all the changes in the structure of the economy that continuous technological advance has caused over the centuries.)

It's OK for governments to spend money for the dominant purpose of creating jobs when they're fighting to urgently reduce the impact of recession. Apart from that, however, the money they spend should be aimed at achieving its nominal purpose. The number of jobs this spending creates should be incidental.

If we continue our muddled thinking about green jobs, we risk having politicians trying to curry our favour by wasting money on schemes that will do little to combat climate change.