Clare Davidson, BBC News 15 May 08;
Vapour trails across the sky makes pollution from planes highly visible. Not so the pollution from the computer industry.
Yet the information and communications technology industry - or ICT - is responsible for the same amount of carbon dioxide emissions as those from planes.
Each year, both sectors emit 2% of total CO2 emissions, though there are signs that the ICT industry is changing.
"In fact, there has been a radical shift in the industry," insists Randy Allen, a vice-president at computer chip firm AMD.
Finite resources
Just as is the case with the aerospace industry, the computer industry has long been driven by one concern - performance. But the better the performance, the more energy it tended to need.
So data centres - the heart of computer networks worldwide - had a vast and ever-increasing appetite for power.
The fundamental problem, explains Jerome Riboulon, manager of Hewlett Packard's power and cooling solutions, is that this model works only as long as energy supplies are plentiful.
"Data centres have begun to reach the physical limit of the energy they can use."
Regardless of the questions about climate change, there simply is not enough available energy, he says matter-of-factly.
Business sense
Another glaring and related issue prompting change in the ICT sector is cost.
Energy efficiency "is a question of fiscal responsibility", says Mr Allen. "It just makes good business sense."
Michael Fahy, managing director of infrastructure services at Lehman Brothers, agrees resoundingly.
"Efficiency and sustainability dovetail to being the same thing," he says.
"Being sustainable is not altruistic. Given rising costs of energy, it just makes business sense."
Energy needs
Given the vast energy demands of data centres, they have been a key focus.
It is commonly estimated that for every pound spent to power machines in data centres, two or three times as much is spent on energy on cooling devices to prevent overheating.
HP, for example, is streamlining its operations by reducing its data centres to six worldwide. Three years ago, it had 85.
The firm spent four years developing a smart cooling technology that links computers and IT equipment, and adjusts how much air conditioning is needed in real time, using only what is necessary.
The technology is aimed at reducing data centre energy use by 25%.
Meanwhile, network supplier Cisco has developed a technology that lets organisations access a so-called wide-area network and move away from multiple networks in different locations, thereby reducing the total amount of IT hardware needed.
What such developments mean in practice varies.
For example, Barclays has adopted HP's cooling technology to reduce its own carbon emissions, while Inchcape Shipping Services has adopted Cisco's wide-area network. This allows an agent on a vessel in Singapore to exchange information with the UK data centre.
And if what a broad-based coalition announced in late 2007 is anything to go by, change is on the cards.
Google, Dell, the Environment Protection Agency and Lenovo launched the Climate Savers Computing Initiative, with new targets for energy-efficient computers and components.
The initiative aimed to cut greenhouse gas emissions by 54 million tonnes, saving more than $5.5bn (£2.75bn) in energy costs. And that was before energy costs soared recently, so the savings could be even greater.
Supply chain
But if data centres gobble up huge amounts of energy, this is only a fraction of the amount the ICT sector is responsible for as a whole, warns Peter Madden, who heads Forum for the Future, a charity focused on sustainability issues.
"There is a huge trail of energy and raw materials used in the supply chain."
UN data suggests that the manufacture of one computer uses 75 times its weight in raw materials and water.
"And of course, there is the energy used over the lifetime of a computer," says Mr Madden.
Mr Madden is among those who say there needs to be a change in design so that hardware is easier to dismantle and re-use, in order to reduce the amount going to landfill, whether it is aluminium chips, plastic or copper cables.
Wider application
With Gartner predicting that the knowledge economy will account for half of Britain's gross domestic product by 2010, the need for change is clear.
In the average office, nearly 40% of emissions come from monitors.
But beyond the office, there is a growing view that the ICT sector could bring about a fundamental change in the way we work, not only to cut emissions but also to create more flexibility for workers.
Mr Madden cites HP's partnership in a DreamWorks animation project as an example of this.
HP's Halo video-conferencing technology was developed for DreamWorks while working with Aardman Animations on a Wallace and Gromit film.
The system was designed to be realistic enough to let creative people in different countries work together to make a Hollywood film without constantly getting on planes.
Such changes would not have been imaginable in the past, he says.
It seems they might be an imperative.
