Engineering news
Radical new ways of removing CO2 from the atmosphere could pose environmental risks, according to a scientist at the University of East Anglia.
New techniques put forward include growing crops to be burned in power stations, large-scale tree plantations, adding biochar to soil, adding nutrients to sea water to boost plankton and seaweed, and using chemicals to extract CO2 from the atmosphere to be buried deep underground.
However, Dr Phil Williamson, employed by the Natural Environment Research Council at UEA's School of Environmental Sciences, believes that most, if not all, of these methods pose environmental risks – and that much more research is needed before the wheels are set in motion on global-scale 'climate geoengineering' schemes.
Writing in Nature, Dr Williamson said: "Crucially, large-scale CO2 removal, by whichever means, will have knock-on effects for ecosystems and biodiversity. There could be benefits, but damage seems more likely.
"For example, the amount of bioenergy crops we would need to grow could use up to 580 million hectares of land – or half of the land area of the US. This would in turn accelerate the loss of forests and natural grassland with impacts for wildlife, whilst also having implications for food security.”
Dr Williamson added: "Very little is known about the effect of future climatic conditions on the yields of bioenergy crops. For example, we don't know what the water requirements of these crops might be in a warmer world.
"It's also important to think about the financial costs of these ideas. For example, adding enough crushed silicate rocks to the soil, over almost half of the Earth's land surface, could cost up to $600 trillion.
"The crucial thing now is that governments and other funding agencies need to invest in new research to investigate the viability and safety of the 'emit now, remove later' approach. Some of the proposed CO2 removal schemes might provide a win-win for climate and the environment; others might be lose-lose. Present climate policy assumes that one or more of them will work at the scale required, yet we just don't know if that is the case."
'Scrutinise CO2 removal methods' was published in Nature on 10 February 2016.