You have to wonder whether the latest emphasis on green IT is much more than a fig leaf. Not a trendy thing to say right now perhaps, but the question is worth asking: how much of this is just so much hot air -- pun intended?

The premise behind the current thrust of green issues in the IT world is clearly that cutting energy use has become non-negotiable. Not only is reduced use of energy derived from fossil fuels good for the environment -- this much is established past the point of reasonable doubt of most individuals, whether scientists or not -- it saves money too. And as energy prices look like they have only one way to go -- like the stock market, there'll be bumps and lumps along the way but the trend is clearly upwards -- cutting energy expenditure is a good thing.

However, the benefits aren't as obvious as they look and for evidence of that, you have only to ask why vendors are falling over themselves to slap a green label on their products. The answer is of course simple: green sells.

From a global perspective, cutting oil-powered energy use is a good thing but compared to the humanity's overall energy usage, IT is not a significant percentage of the whole.

In a 2006 report for the UK government by Sir Nicholas Stern on the economics of climate change, IT is hardly mentioned as a culprit. Where it is mentioned, as Ovum analyst Stephen Young points out, the issues aren't data centres and more efficient processors. Instead, it's about transport, says Young: "The strategic use of ICT can contribute significantly to energy efficiency (which Stern does pick up on), sustainable economic growth and job creation. ICT can reduce the need for travel and transportation of goods by bridging distance. It can increase efficiency and innovation by allowing people to work in more flexible ways, and can ensure a shift from products to services..."

Young highlights another report, prepared as a joint initiative by the European Telecoms Network Operators and the World Wildlife Fund, which notes that users of IT can contribute significantly to carbon emission reduction by travelling less and using more video- and audio-conferencing instead, flexi-working which cuts the cost of commuting, and making more transactions online.

Again, the energy used by data centres is hardly mentioned. The reason, which becomes clearer when you look at the overall picture, is that IT is not a major villain here. The major oil-burners are transport, energy production and industry. As a 2007 report from Gartner points out, the global information and communications technology industry uses two per cent of the global total.

This is not to say that those in the IT industry and its customers shouldn't be making efforts to reduce carbon emissions: far from it. However, this is an effort to put things into a global perspective when IT vendors come calling with products sporting green labels.

That said, the IT industry has its part to play and, unlike many other industries, energy is a major cost for IT users so there's a clear incentive to reduce usage.

You've seen many articles in these pages on the power-saving processor designs from AMD and Intel, and their implications for servers and data centres. Very few of these pieces have been about green issues and for good reason. Saving power in the data centre and elsewhere is primarily about lowering energy bills, not being green.

However, especially if you're an enterprise with a public face, it does no harm to audit energy reduction and so claim a footprint in the overall carbon emissions story. It's good PR.

Close your business and reduce emissions

But being truly green doesn't involved cutting expenditure on energy: it means going out of business. How so? One of the biggest contributors to carbon emissions is industry. Making and delivering products and services, plus the processes that go along with it -- especially transport, without which no business could function -- are all energy-intensive.

And the drive towards higher profits as demanded by shareholders -- which is, after all, one of the fundamental underpinnings of capitalism -- looks unlikely to disappear. This means more energy use, not less. Even if we all reduce the growth in energy use, we're still using more, which is not green. And neither are products that provide 20 per cent more compute power for only a 10 per cent increase in energy use.

Green might be good for the planet -- but let's not kid ourselves that using more is being green because it simply isn't.