IMechE pushes for geo-engineering

The Institution of Mechanical Engineering (IMechE) is urging the UK government to support geo-engineering technologies that could help reduce CO₂ levels in the atmosphere.

In a report called ‘Geo-Engineering - Giving us time to act?’ the IMechE argues that current carbon-reduction initiatives are not working fast enough to mitigate climate change.

It claims that a combination of skills shortages and technologies that are ‘still a significant way from being ready’ will mean that the UK will fail to reach its target of an 80 per cent reduction in carbon by 2050.

The report proposes a climate change roadmap over the next 75 to 100 years, in which geo-engineering techniques are used to buy the country more time by removing large quantities of carbon from the atmosphere.

These techniques include the deployment of so-called artificial trees that use chemicals to replicate absorption of carbon dioxide. The device works by attracting CO₂ to a sorbent material on the ‘leaves’, which is then removed and buried underground in the same way as conventional carbon capture and storage (CCS).

Tim Fox, head of environment at IMechE and chief author of the report, said: ‘With today’s technology, it would take in the order of 10 million artificial trees to collect 3.6 GT/year of the total 29 GT/year of global CO₂ emissions.

‘However, with technological improvements, it should be possible to improve the trees capability by the order of 10. This would mean that five million trees would be able to comfortably capture all the non energy sector emissions of the plant.’

Fox added that the artificial trees would have the advantage of using a relatively small amount of land while being several thousand times more effective than real trees. He also claims the technique will address the reduction of atmospheric CO₂ irrespective of its source and proposes locating the trees alongside motorways where CO₂ concentrations are particularly high.

A further proposal to absorb CO₂ through photosynthesis is also outlined in the report. It refers to existing techniques that make use of algae in large open spaces to capture carbon. However, due to limitations in available land, the report suggests an alternative would be to pipe algae around building exterior in plastic bioreactors.

There are a number of technical barriers to this proposal that include its integration into architectural design and cost of the technology. The report states that a third and more cost-effective suggestion is to make building surfaces more reflective to reduce the amount of solar radiation absorbed by the Earth’s climate.

The IMechE claims that funding of £10m by the government for these technologies will boost British industry and create 500,000 jobs by 2020. The report urges the government to consider geo-engineering as a priority rather than a ‘Plan B’ in order to give the global community extra years in which long-term carbon-emission strategies could be adopted.

The report concludes: ‘Given the lead times likely to be associated with the development of engineering schemes on this scale, it is important to urgently instigate research and assessment activity, so that the technical community can be prepared for the potential “emergency” deployment of geo-engineering systems.’