Producing biofuels from food crops is at best a temporary measure to satisfy political demands to make consumers’ energy consumption greener.

In the long term it is unsustainable, as is much of modern, artificial fertiliser-based agriculture.

The claim was made at a press briefing on Monday (9 July) organised by the science and research body the Royal Institution. The briefing was aimed at outlining research to help farmers adapt to climate change.

Second generation biofuels made from relatively low input perennial crops like miscanthus, willow and poplar offered a much more promising way forward and the potential of GM crops could not be ignored, scientists said.

David Powlson of Rothamsted Research explained planting trees on set-aside could save an estimated 4% of the EU’s carbon dioxide emissions that are believed to contribute to global warming.

But there was huge debate about the carbon savings involved in making bioethanol from crops like maize. “At best it’s marginal.”

Biofuel from palm oil diverted from, say, margarine making, would be more acceptable, but destroying rain forests to increase production was wrong, said Prof Powlson. “It’s a con.”

“Getting the energy balance right is critical,” added Giles Oldroyd of the John Innes Centre.

Biodiesel from oilseed rape was a non-starter, said Dr Oldroyd. “Forget it – it’s barely breaking even.”

Nitrogen and phosphate fertilisers had been key to improving crop yields. “They were part of the green revolution.”

But with 80% of the energy used in growing wheat accounted for by N fertiliser manufacture and with rock phosphate sources being used up fast, alternative ways of feeding crops were needed.

The best way to do that was to manipulate crops to allow them to mimic legumes which worked with soil micro-organisms to extract all the nutrients they required naturally.

The “magic bullet” for breeders was wheat that worked in that way.

Switching from ploughing to reduced cultivations had a big role to play in reducing carbon emissions, said Syngenta’s Jeremy Dyson. But while the USA offered incentives for farmers to move to so-called conservation tillage, the EU had yet to do so.

Given the potential that GM crops offered, Dr Oldroyd said they represented a “minor issue compared with climate change”.

andrew.blake@rbi.co.uk