By Roger Harrabin
BBC environment analyst
In some markets wheat is currently fetching about $300 a tonne
Politicians struggling to solve the current world food crisis need to find long-term solutions that feed the poorest without reproducing the ills of the recent "cheap food era".
In the late 1990s, the wheat price was at a record low - driven down by inexpensive fuel and taxpayers' farm subsidies in the EU and America.
Cheap food encouraged an epidemic of obesity in which the number of people overweight (one billion) globally exceeded the number of malnourished (0.8 billion).
It sparked an orgy of food waste, with people in some countries throwing away a third of what they buy.
It benefited consumers throughout rich nations, and in cities of the developing world.
But farm surpluses dumped on developing countries drove poor farmers out of business and helped persuade politicians in Africa that supporting domestic agriculture was a low priority.
The UN Food and Agriculture Organisation (FAO) warns that food prices will not return to their previous low level for the foreseeable future. But many analysts doubt that they will ever sink that low again - and regard this as a benefit rather than a curse.
"Food has been too cheap for too long," says Professor Tim Lang at City University, UK.
Already the market is responding to higher prices. Argentina is forecast to profit from a boost in agriculture, and Ukraine will cash in by bringing derelict land back into service.
It is reported that farmers in Afghanistan are turning from opium to wheat because it pays more at current rates.
But as well as providing a short-term safety-net for the hungry poor, the politicians at the UN want to stimulate agriculture worldwide - particularly in Africa where all nations are net losers from high food prices.
Their farmers will benefit from the price rise if they can improve outputs.
Meanwhile, they will try to persuade India which is stock-piling rice to release it on to world markets. But they may struggle.
Economists promote free markets as a solution to high prices but for countries such as India, food security is a key political issue - and food politics may grow more rather than less acute as the century progresses.
This will undoubtedly be so in Europe as we move towards the next great reform of the Common Agricultural Policy in 2012.
The UK has been pushing for freer markets and a complete end to direct payments for farm production - but the French farmers have seized the current crisis as the ideal opportunity to push their ideal of a Europe less dependent on food imports.
British policy on the issue is evolving, too. All this friction is likely to cause further jams to the lurching world trade talks.
The open question is whether the planet will be able to feed a population of nine billion by the end of the century. Some food experts are sceptical about whether this can be achieved.
But Prof David Harvey, from Newcastle University, UK, forecasts: "It's hard to be certain but I think it's far more likely that the world will run out of tolerance before it runs out of food. The problem as always is how the food is distributed."
That means potentially increased conflict between people rich enough to waste food and people so poor that they can't afford to buy it.
A paper from the "think-tank" Chatham House outlines four possible scenarios:
- Just a Blip - the present high price of food proves to be a brief spike with a return to cheap food at some point soon
- Food Inflation - food prices remain high for a decade with oil at $100 a barrel
- New Era - politicians accept that current food production is unsustainable and shift to eco-technological farming
- Food in Crisis - a major world food crisis develops with oil at $200 a barrel; the world in recession and food stocks exhausted
Underlying these scenarios are questions of how the environment will cope with all the increased agricultural demand.
Every farm expansion affects wildlife. Water is already scarce in many areas and will have to be used more frugally.
Computer models of climate change cannot offer good guidance on whether key agricultural areas will become drier or wetter in future. But every hectare of virgin land ploughed for agriculture releases more carbon from the soil.
The Intergovernmental Panel on Climate Change projects that agricultural productivity will increase for the first few decades of the century, but will then begin to fall as temperatures rise further.
There are many uncertainties - except this: one way or another, food is likely to remain a key issue.
The FAO has convened a meeting in Rome, Italy, over the next three days which will discuss world food security, climate change and bioenergy.