Global food prices are likely to keep rising as production struggles to match demand and extreme weather events become more frequent, a climate-change advisor to the Australian government said on Wednesday.

Ross Garnaut told an agricultural outlook conference that more severe weather events were inevitable, given climate change was "already in the system".

"There is going to be a growing intensity of adverse weather events so there is a need to respond to this," he said.

Garnaut said Australian farming would be deeply affected by climate change but could also benefit from by its ability to generate carbon credits through carbon sequestration -- the process of conserving or boosting carbon content of soils via techniques such as low-tillage farming.

"So the general environment for Australian farming is going to be one of greater opportunities. It will be partly from wider opportunities to earn income, one of which will very large indeed, associated with bio-sequestration, as well as rising food prices," he said.

He said prices for farm products had fallen in real terms in the second half of last century after a "green revolution" had boosted productivity, but this was no longer the case.

"There will be a reversal in the 21st century...long-term trends suggest that food prices will increase fairly strongly," he said, citing population growth, rising prosperity and the devotion of more farm land to biofuel production.

Demand for higher protein food in fast developing countries such as China was increasing pressure on livestock feed supplies while government policy was increasing the demand for biofuels.

"Mandatory requirements for use of biofuels is taking land out of food production for biofuel production...that has had a significant effect for grain and oilseed prices," said Garnaut. – Reuters