After decades of concern over the West's food mountains, the world is facing the prospect of not enough food to go around

Over the past 20 years the world has become concerned about the consequences of global warming. But it is only in the past few months that the most dangerous possible consequence of this change - a global shortage of food - has become a possibility. The prices of most cereal crops - wheat, barley, maize as well as soya and palm oil - have doubled or even trebled in the past two years. Could it be that in a world whose population is growing fast and where climate change may prevent farmers from increasing their outputs, there may not be enough food to go around?

In recent years, the EU and the US have been more concerned about what to do about food surpluses than shortages, because, following the Second World War, farmers were encouraged to produce food irrespective of cost, resulting in mountains of surplus food, this despite a trebling of the world's population in my lifetime. The oversupply of food in affluent parts of the world has caused the price of food to drop dramatically, leaving people with more money to spend on other consumer goods.

However, supermarkets are not the cause of the problem that farmers complain about. The cause is supply constantly running ahead of demand. There are three main players as the planet faces climate change and food security: the scientists, the Luddites and self-indulgent consumers.

Science is the key to solving both problems. In the case of climate change, we need scientists to determine trends, to develop environmentally friendly sources of energy and improve energy efficiency. As for food, only innovative and responsible scientific development will avert a potentially disastrous food shortfall. Both issues can only be tackled on a global basis and require an unprecedented level of international agreement.

Governments must agree on regulations to restrict emissions, to invest heavily in research and to ensure the benefits of such research are shared globally. There will be a catastrophe if trade agreements restrict the movement of affordable food from regions in surplus to those in deficit. There are those who would seek to resist scientific innovation such as GM. To them I would say that it is one thing to question the benefits of scientific development, quite another to deny scientific progress or suggest that the world can survive without it. It cannot.

Finally, there is the crucial problem of irresponsible behaviour, particularly in affluent consumer societies where thoughtless self indulgence leads to unnecessary waste of energy and food - 50% of our food supply is currently wasted, which is a shameful statistic. How far can governments go in restricting such excesses without losing the support of the voters? Taxes are an option but are notorious vote losers. Regulations are equally unpopular and almost impossible to enforce.

Governments must speak with one voice in informing their citizens of the developing situation. They must emphasise the ways ordinary citizens, in making significant but manageable changes to their routines, can play a decisive role in avoiding disaster.

It will be a tight call but I believe that through a combination of scientific innovation, well thought-out taxes and incentives, effective regulation, international co-operation and the inherent common sense of most human beings, we will avoid a disaster in food supply. n

Excerpt from Lord Haskins' City Food Lecture last week