Here is the good news. Bong: billions of people are prospering their way out of poverty, and able to buy enough and better food for their families. Bong: massive investment in developing alternatives to oil is combating the threat of climate change. Bong: hard-pressed farmers plan on good times ahead. Bong: Europe's obscene mountains of grain and butter are no more - there's only wine left.

The headlines are heart-warming, but they add up to a whole lot of trouble. Food prices are soaring globally, and economists reckon this is no market blip. From Beijing to Buenos Aires and Mumbai to Marrakesh, the growing demand for rice, wheat and soya, and even more so for meat protein, is fuelling demand. Populations are rising, but rapid growth in middle-class numbers, notably in China and India, is rising much faster. It is as income rises in the £1 to £5 per day range that much of that extra is spent on food basics. Above that, it goes on processed food, which means more energy use, too.

Developing countries have lots of catching up to do: the average Chinese man has doubled his meat consumption in 20 years, yet his Taiwanese neighbour eats nine times more animal protein. A kilo of beef requires up to eight kilos of grain, plus fuel costs and much more water. With booming demand, Chinese pork prices have risen 48% in a year and the price of rice has doubled in five years. A recent stampede for scarce cooking oil cost three people their lives.

Global supply is being hit by much of America's grain being diverted to biofuels, following President Bush's decreed shift to ethanol production. This was at least as much to reduce his country's dependence on oil imports from hostile parts of the world as to tackle global warming. American grain stocks are down to their lowest level since it was feeding war-torn Europe in the 1940s.

Europe is also aiming to push for one in 20 litres of transport fuel being crop-based, while Richard Branson is boasting how his aircraft can now fly on friendly fuels. But forests are being cut down to feed biofuel demand, a process described by the UK government's chief scientific adviser as "profoundly stupid".

Food price pressures are being felt around the world. They have caused riots in Mexico, Morocco, Uzbekistan, Yemen, Guinea, Mauritania and Senegal. A protest in Beirut, where food prices nearly doubled in four months, led to nine deaths. Russia has imposed price controls on staple foods. Pakistan has stationed troops around flour mills. The market price of rice in India has risen by half in a year, and its govern-ment recently blocked rice exports except for the premium basmati that finds its way on to British plates.

And that is where this looming crisis comes home. The average British household spends only £1 in eight on food. A couple of generations ago, that was nearly £1 in three. Food has been cheap, and with tough competition in British retail, the impact of rising global food prices has been relatively subdued.

But British food inflation is accelerating. Last month, it reached 4.6% year-on-year. Politically, it is part of a picture of rising inflation, even more pronounced in fuel costs, with which Chancellor Alistair Darling has been wrestling ahead of tomorrow's Budget. The issue for him is how to dampen inflation while using punitive taxes to discourage oil consumption and binge drinking. But the issue is also for consumers. Unlike the other big threats that dominate international relations - climate change, what happens when the oil runs out, water disputes, the risk of terrorist attack - the gathering food crisis is right here and right now. British shoppers can afford a bit more, though we may have to increase the share of spending that goes on food. We won't like that, but we should remember we are buying from the same global market-place in which the poor have to compete - today, tomorrow and beyond - if they are to have anything for their next meal. And with biofuels, we have reached that even more uncomfortable position where filling the petrol tank means someone can't afford enough bread, rice or noodles.

The response to these global challenges has been to manage, design and invent our way out of them, and go on as before. Technological solutions are seen as the way to make engines more efficient or to rely on non-oil fuels. Don't be surprised when the GM-crop lobby uses the fear of growing food shortages as a justification for more extensive planting.

But there is something different and more immediate about food, going beyond reliance on politicians and scientists to sort something out. It is a direct challenge to individuals' choices, that if food production can't keep up and others are to have their fair share of scarce resources, we simply cannot go on buying, eating and wasting more than we need.