Breeding deeper-rooted crop plants could dramatically lower CO2 levels in the atmosphere, a University of Manchester scientist claims.
Professor Douglas Kell argues that this would allow more carbon to be harvested from the air, as well as making crops more drought resistant.
Kell has calculated that if present croplands were covered with plants that have roots a metre deeper in the soil, the amount of carbon captured from the environment could be doubled. It's happened before: the long-ago rise of deep-rooted trees and flowering plants is known to have caused massive CO2 reductions in the atmosphere.
"This doubling of root biomass from a nominal 1m to a nominal 2m is really the key issue, together with the longevity of the roots and carbon they secrete and sequester below-ground," says Kell.
"What matters is not so much what is happening now as what might be achieved with suitable breeding of plants with deep and reasonably long-lived roots. Many such plants exist, but have not been bred for agriculture."
In addition, says Kell, such plants seem to mobilise and retain nutrients and water very effectively over extended periods, providing resistance to drought, flooding and other possible effects of climate change.
"While there is a way to go before such crops might have, for example, the grain yields of present day cereals, their breeding and deployment seems a very promising avenue for sustainable agriculture," he says.