"We've gone from feeding three billion people on 1.3bn hectares 50 years ago to feeding seven billion on 1.5bn hectares thanks to fertilisers and pesticides," he said.
"But ammonium nitrate, the fertiliser for agriculture, takes vast amounts of fossil fuel to make. The Haber-Bosch process requires 450 degsC and pressure of 300 atmospheres. Could this be made on a smaller scale using sustainable power? The newly developed ruthenium-PNP complex lets you do it at 50 degsC and one atmosphere."
He added that for the other two main components of commercial fertiliser: "Phosphate gets into rivers and causes eutrophication. It would be better to extract it from sewage." But this option is as yet unavailable for potash, of which there are still "massive reserves".
Several forms of sustainable fuels are also set to grow greatly, with bio-refinery firm Ensus "now going back into production of bioethanol from wheat" in what will be Europe's largest such refinery on Teesside, now that the US has dropped subsidies to its own bioethanol industry.
A plant is also being built in Hull to turn surplus sugar beet into bio-butanol, said Emsley, and biomass will also have a growing role to play in production of bio-polymers.
He also forecast that extracting methane from waste and unused food, and even from old landfill sites, "will be all over Britain soon".