Ministers will this week embark on a campaign to curb "cyber-warming" from computers and information technology equipment that now does as much damage to the climate as aircraft emissions. Meanwhile, the Health Protection Agency is to start measuring levels of radiation from Wi-Fi systems in response to mounting concerns.

The two initiatives will mark the biggest official attempt to address some of the environmental consequences of the extraordinarily rapid spread of IT into almost every aspect of daily life. Up to eight million new computers are sold in Britain every year, along with 1.8 million Wi-Fi terminals in the past 18 months.

A government-backed task force is to launch an attempt to reduce what it calls the "cyber carbon footprint" - which threatens to wreck attempts to hit targets for reducing emissions of carbon dioxide, the main cause of global warming - and to encourage the spread of "green" technology.

New research shows that computers generate an estimated 35 million tons of the gas each year - the equivalent of one million typical flights to and from the UK. And Gartner, the international information technology research company, estimates that globally the IT industry accounts for around 2 per cent of carbon dioxide emissions - much the same as aviation.

It takes around 1.8 tons of chemicals, fossil fuels and water to produce a PC, and its operation generates 0.1 tons of CO2 in a typical year. They last, on average for three years and, once junked, most are buried in landfill. The soil where they are buried can become polluted with cadmium and mercury. Many PCs are sent to dumps in China and Africa: 100,000 old PCs arrive in the Nigerian city of Lagos each month from Europe and America.

Ministers are worried that they are not doing enough to counter the effects on the climate of an explosion in the use of IT technologies, which include iPods, Blackberrys and mobile phones, as well as PCs. They expect, for example, that the number of energy-intensive flat-screen TVs will increase dramatically - to around 67 million sets by 2010 - consuming far more energy and producing far more carbon dioxide than traditional sets.

Ian Pearson, the environment minister, estimates that by then TVs will produce 1.7 million tons of carbon - up from 1.1 million tons today. The new project, which will be led by Manchester City Council, is designed to produce a computer network that requires 98 per cent less energy to operate. Phil Woolas, the local government minister, said yesterday: "This is the first time a national IT project has focused on climate change in this way and has the potential to be critical in helping us reach our sustainability targets."

Dubbed Green Shift, the project will replace energy-absorbing PCs with greener alternatives in up to 10 cities by the end of 2009. It aims to change the way computers work and how they deal with email and internet surfing. Green data centres will host services such as email and deliver them using non-fossil-fuel power. People will be able to access the service through a small desktop box rather than having to have their own "energy-hungry" PC.

At the same time, green groups are launching a campaign to press computer manufacturers to cut their carbon footprint. They want companies to make it easier for people to upgrade their computers rather than replacing them every few years - and they want computers to use less energy. The Health Protection Agency's move follows concerns about the effects on Wi-Fi, particularly in schools, by its chairman, Sir William Stewart, first reported in The Independent on Sunday in April, and followed up by BBC's Panorama programme last month.

Sir William, a former government chief scientist, called for a "timely" review of the possible effects of the technology, which some scientists say could cause a worrying range of conditions from headaches to concentration difficulties to heart disease and cancer. The agency has long been more sanguine about the technology than its chairman, and initially sought to cover up his concerns. Now it has been forced by public concern to take a small step towards addressing the issue by taking measurements in classrooms. But it has no plans as yet to monitor any effects on children's health.

(By Marie Woolf e Geoffrey Lean, The Independent, 10/06/2007)