Food security moved higher up the political agenda at Holyrood this week when Conservative opposition spokesman for Rural Affairs and the Environment, Ayr MSP John Scott, led a debate on the subject.

He told Holyrood: "From 1988 to 2008 we have had, in an almost biblical way, 20 years of plenty, but the situation has now changed. Once again the spectre of food shortages has emerged, with world grain prices rising by 60% in the first three months of this year and China buying land in Russia and South America to feed its growing population.

"The problems that we are contemplating today have come about for three main reasons. First, oil - unexpectedly - has reached $120 a barrel, largely because of the growing awareness that oil is a finite resource and because of concerns about peak oil. That has encouraged farmers worldwide to grow crops for biofuel production on land that was previously used for food. In Brazil, for example, 90% of new cars now run on ethanol.

"Secondly - and again unexpectedly - global warming is taking more and more land out of agricultural production both north and south of the equator. Australia has suffered a seven-year drought and much of southern Europe and North Africa is a virtual desert in terms of food production. Sea levels are beginning to rise too.

"Although no-one can tell us by how much they will rise, we know that a one metre rise in sea levels - a distinct possibility within the next 100 years - would reduce by a third the land that is available to feed an already hungry world.

"The third reason for the problems that we are examining today is population growth and rising standards of living. Man has been the most successful species since the dinosaurs and the world's population is heading towards nine billion by 2050.

"Increased living standards, especially in China, India and Japan, have resulted in those countries moving to Western styles of food consumption, based on consumption of meat rather than rice or grain. That has put still more pressure on grain growing, so that animals can be raised for human food consumption."

Scott warned MSPs that "the perfect storm is emerging, due to rising oil prices, global warming and world population growth. Today, we must acknowledge those facts and start to consider what we in Scotland can do to help feed a daily more hungry world".

Labour MSP Karen Gillon (Clydesdale) was equally concerned about food security and its impact on the poor. She told Holyrood: "In the developing world - in countries such as Malawi - we can see just how extreme weather events are impacting on food security.

"In 2005, I saw at first hand how devastating drought had been to food production in Malawi. This year the food supplies of many people have been placed at risk by flooding.

"Malawi contributes little to our emissions, but her people suffer disproportionately. Both here and in countries such as Malawi, food security is intrinsically linked to poverty. The poor in Scotland suffer most from rising food prices that force them to limit their food intake and to reduce the variety of foods that they eat.

"In Malawi, it is the poor who face starvation as their crops - their only source of food - are wiped out.

"Can members really imagine what it would be like not to know where their next meal was coming from, or whether it would ever come?"

Gillon went on to lambast the use of biofuels. "Tackling climate change is crucial and reducing emissions is paramount, but the consequences for the rest of the world of solutions to these problems must be more thought through than the perverse rush to biofuels has been.

"I say perverse' because it is undeniable that biofuels take food out of the mouths of starving people and divert it to be burned in the car engines of the world's richest people.

"In the words of the United Nations' Special Rapporteur on the Right to Food, Jean Ziegler, that is nothing less than a crime against humanity'. Are we really prepared to sit back and say to the world starving millions: We'll burn your food in our cars while your children die around your feet'?

"Next year, the amount of corn used for ethanol in the US is forecast to rise to 114 million tonnes - nearly a third of the projected crop.

"American cars now burn enough corn to cover all the import needs of 82 nations that are classed by the Food and Agricultural Organisation of the United Nations low-income, food deficit countries. If that is not perverse, I do not know what is."