http://www.timesonline.co.uk/tol/news/environment/article6811264.ece

Giant fly-swat shaped “synthetic trees” line the road into the office, where blooms of algae grow in tubes up the walls and the roof reflects heat back into the sky — all reducing the effects of global warming.

All this could be a familiar sight within the next two decades, under proposals devised by the Institution of Mechanical Engineers to alter the world’s climate with new technology.

A day after John Prescott, the former Deputy Prime Minister and Environment Secretary, warned that negotiations for a global deal to cut carbon emissions were in danger of collapsing, the institution is recommending a series of technical fixes to “buy time” to avert dangerous levels of climate change.

It says that the most promising solution is offered by artificial trees, devices that collect CO2 through their “leaves” and convert it to a form that can easily be collected and stored.Tim Fox, head of environment and climate change at the institution, said that the devices were thousands of times more effective at removing carbon from the atmosphere than real trees.

In the first report on such geo-engineering by practising engineers, the institution calculates that 100,000 artificial trees — which could fit into 600ha (1,500 acres) — would be enough to capture all emissions from Britain’s homes, transport and light industry. It says that five million would do the same for the whole world.

Dr Fox said that prototypes had been shown to work using a technology, developed by Klaus Lackner of Columbia University in New York, that isolated CO2 using low levels of energy. “The technology is no more complex than what is used in cars or air-conditioning units,” he said.

Professor Lackner estimates that in production the units would cost $20,000 (£12,000) each, while the emissions associated with building and running each unit would be less than 5 per cent of the CO2 it captures over its lifetime.

“The trees could be located in artificial forests close to depleted oil and gas reserves,” Dr Fox said, allowing captured carbon to be stored underground. He added that “it would also be logical to put them by the side of highways”, capturing CO2 from traffic.

The report recommends that algae be grown in plastic tubes down the side of buildings, where it would take in CO2 from the air. The algae could even be used as fuel in photo-bioreactors, providing energy to generators while using the CO2 emitted to grow more algae. This technology has yet to be tried as a working system, however.

More elaborate solutions, such as launching giant mirrors into space to reflect the sun’s rays, are ruled out by the report, which says they are too expensive, unpredictable and could have dangerous side-effects on weather systems such as rainfall.

However, the institution does recommend more limited use of reflective surfaces on buildings. Although this would not reduce global warming overall, it would cool sweltering cities and reduce energy used in air-conditioners by between 10 and 60 per cent, the report says. At its simplest, this could involve simply painting walls and walls white. But smart materials could reflect infra-red light — which makes up about half of solar radiation — without dazzling people.

Dr Fox emphasised that geo-engineering should not be a substitute for cutting emissions. But the institution is lobbying the Government to drop its opposition to supporting research into such technology and contribute between £10 million and £20 million to research. “We are urging government not to regard geo-engineering as a plan B but as a fully integrated part of efforts against climate change,” Dr Fox said.

A spokesman for the Department of Energy and Climate Change said: “Our primary aim must be to deliver a global deal which cuts global emissions. It’s clear that geo-engineering technologies are undeveloped and untested and at present remain a long way from being practical solutions to an urgent problem.”