Fake trees, algae tubes and white roofs among UK engineers' climate solutions

Report from Institute of Mechanical Engineers calls for £10m to develop geo-engineering ideas that would be 'an integral part' of the solution to global warming
Alok Jha, The Guardian 27 Aug 09;

Artificial trees and tubes of algae on the sides of buildings could absorb most of the UK's annual carbon dioxide emissions, according to a report from engineers that will be circulated at party conferences in the autumn.

In research examining the role that geo-engineering could play in tackling climate change, a 12-month study by the Institute of Mechanical Engineers (IME) also found that painting city roofs white could also prove to be a simple but effective way to curb excessive global warming.

Geo-engineering is a set of technologies that could prevent or slow global warming - it includes everything from sending mirrors into space to reflect away sunlight to dumping iron into the oceans to encourage the growth of algae, thereby removing atmospheric CO2. For their study, the IME searched for ideas that were most practical and could have impacts on CO2 or global energy use levels as soon as possible.

Setting out their recommendations in a report published today, the IME called on the British government to put up £10m aimed at turning the three most promising ideas into reality. They advocate this being part of a £100m global fund for geo-engineering research.

"Geo-engineering is no silver bullet, it just buys us time," said Tim Fox of the IME, who led the study. "We're not proposing that geo-engineering should be a substitute for mitigation [but] should be implemented alongside mitigation and adaptation."

Top of their list of practical solutions that would be low-carbon to build and require only existing technologies were artificial trees. These units, invented by Columbia University scientist Klaus Lackner, would be the size of a standard shipping container and could remove CO2 directly from the atmosphere. "100,000 trees would take up an area of around 600 hectares, which is less than 10% of the surface area of the Firth of Forth, and that would be able to absorb the CO2 emissions of the UK's non-power sector annually," said Fox.

Currently the UK produces 556 megatonnes of CO2 per year and the 100,000 trees could absorb around 60% of that amount. The engineers calculated that forests of artificial trees powered by renewable energy and located near depleted oil or gas fields, where the trapped CO2 could be buried, would be thousands of times more efficient than planting trees over the same area.

Making each artificial tree would require energy and materials but this would only account for 5% of the CO2 that the device could capture in its lifetime. On a global scale, between 5-10m artificial trees could absorb the CO2 emitted from all sources other than power stations.

Another geo-engineering solution highlighted by the engineers was attaching tubes filled with algae to the sides of buildings. "Algae is a naturally-occurring eco-friendly biomass that tends to have a high level of CO2 use in photosynthesis," said Tom Bowman of IME. The algae that grows can be collected and turned into charcoal, which can be buried so that the CO2 it has captured is locked away from the atmosphere.

Painting roofs white was recommended by the engineers to counteract the urban heat island effect, where major cities can be up to 4C hotter than their suburbs. This means more use of air conditioning or other cooling methods and it also speeds up the formation of smog. The IME said that reflective roofs can reduce the energy use of a building by up to 60%.

Fox said that global carbon emissions had continued to rise despite two decades of attempts at mitigation, so geo-engineering should not be regarded by policymakers as a plan B, but an integral part of the solution to global warming. "£10m would get us significantly far forward in terms of sorting out the wheat from the chaff in this debate," he said. "The government can then look at piloting them and testing them in the field and then making decisions about their deployment."

'Fake trees' could fight climate change
Forests of "fake trees" should be planted across the country to reduce the impact of climate change, according to a study.
Ben Leach, The Telegraph 27 Aug 09;

Experts claim the devices would be able to soak up carbon dioxide from the atmosphere. 100,000 of them would remove the carbon emissions of every car, lorry and bus in Britain.

The scientists argue that a single synthetic tree, which would be two-thirds as tall as a wind turbine, could capture ten tons of carbon dioxide from the air every day, making it thousands of times more efficient at absorbing CO2 than a real tree.

The study, by the Institution of Mechanical Engineers, into how technology could prevent climate change argues that using technology to remove CO2 from the atmosphere could buy the world vital time.

The trees, which would cost around £15,000, would be coated with synthetic materials that absorb CO2, which would then be removed and stored underground in depleted oil and natural gas reservoirs.

The study also calls for pots of algae that absorb CO2 from the atmosphere to be used to line buildings. The algae could then be used as green biofuels for cars.

Painting buildings white can also help reduce the amount of solar radiation absorbed by the Earth, keeping it cool. The institution wants millions of pounds to be invested in research on technology to beat the threat of global warming to Britain.

Dr Tim Fox, one of the report's authors, said: "Geo-engineering may give us those extra few years of transition to a low- carbon world and prevent any one of the future climate change scenarios we all fear."

The report also claims that unless we act soon global warming will continue unabated and predicts that global temperatures could increase as much as 6c by 2100, creating food and water shortages, sea level rises and massive refugee crises.