The Big Question: Why is so much of the world still hungry, and what can we do about it?

Why are we asking this now?

Because the number of people who go to bed hungry every night somewhere in our world has reached 1 billion – one in six of the Earth's population, according to a new report by the United Nations' Food and Agriculture Organisation. The international goal of slashing in half the number of hungry people by 2015 now seems far from attainable.

But it need not be so. Undernourishment fell across the world throughout the 1980s and early 1990s. But then in 1995 things went into reverse. Today there are more hungry children, women and men than at any time since 1970. Last year 46 million extra people fell below the UN poverty benchmark of having less than $1.25 to live on every day.

Why have things deteriorated so?

For a complex variety of reasons – some linked to the global recession, some to medium-term political changes on matters like biofuels, while others relate to more deep-rooted structural changes.

What's the immediate problem?

The world economic crisis has choked off the short-term financial credits which poor countries need to buy food on the market. And because developing countries have become more integrated into the world economy they have become more vulnerable to volatile price changes in international markets.

The current economic crisis affects so many parts of the world simultaneously that it reduces Third World governments' scope for using coping mechanisms that worked in the past, like currency devaluation.

Increased worldwide unemployment has also reduced the amount of money that foreign workers abroad are able to send home – and though the drop has not been as bad as some predicted, the picture is expected to worsen as unemployment rises in developed nations.

All this comes on top of the massive surge in worldwide food prices two years ago.

So why did food prices soar?

Things were triggered by the 2007 drought in Australia, the worst for a century, which halved its wheat harvest. But there were more fundamental background factors.

As countries like China, India, Brazil and Russia have got richer they have begun eating more. Rich people don't just eat more than poor people, they eat differently. The demand for meat in developing countries has doubled since 1980. In India it is up 40 per cent. In China the rise is 150 per cent. And because cattle and chickens are fed on corn – it takes 8kg of grain to produce 1kg of beef – the price of all cereals has been forced up.

Added to that was George W Bush's lunatic love affair with American biofuels. Instead of buying plant ethanol from sunshine states like Brazil, the Americans have been trying to grow their own – with oil-based fertilisers and by subsidising US farmers. A third of its maize crop goes to fuel cars, in a bid to lessen its dependency on oil from dodgy dictators in the Middle East. The price of cereals has rocketed as a result.

Then, as food prices spiked between 2006 and 2008, speculators began hoarding food, and grain-producing governments slapped hefty export taxes on it. The prices have fallen a little in the past year but they are still 80 per cent higher than four years ago. And the coping margins for poor people have reduced; they have already sold off many of their meagre assets.

Why don't poor nations just grow more food?

That brings us to the long-term structural issues. Even before the spikes in food prices, world hunger had been increasing slowly but steadily.

Both aid and investment in agriculture have been in decline since the mid-1980s. As the population of developing countries shifted to the cities, local agriculture was seen as less important, since cereals could be imported in huge quantities from grain-producing countries in many of which, like the US and EU member states, farmers were subsidised to keep them in work and ensure secure food supplies at home. The surplus could be dumped on the Third World, making agriculture there less economically viable.

Investors switched their money from agriculture to more profitable areas. Aid followed the trend. In 1980, 17 per cent of global aid went to agriculture; by 2006 that had fallen to 3.8 per cent. Aid was switched to debt reduction, health and education, and building up the capacity of Third World governments.

It was only in July at the G8 summit in L'Aquila that this policy was thrown in reverse with a pledge of $20bn more aid for farmers in poor countries. But it will come over three years and take many more years to bear fruit.

What about the effects of climate change?

That will make things even worse. A study this week suggests that global warming will reduce farm production by 12 per cent in Africa by 2080 – with output falling by as much as 60 per cent in some countries.

What can be done about all this?

A list of answers to that question could be very long. Here are some measures that could be taken:

Aid should rise from the current $8bn a year to $44bn and be spent on irrigation, modern machinery, roads and training for small-scale farmers as well as on high-quality seeds, fertilisers, feed and technologies that would boost both production and productivity.

International funds to make investment more attractive should be beefed up.

Trade policy should be reformed to enable poor farmers to sell high-value products like specialist vegetables and flowers to the West without huge taxes and tariffs.

We should stop subsidising our farmers to produce too much which they then dump on the developing world, destroying the market for local crops. (The OECD spent $265bn on that last year compared to a measly $4bn on aid to Third World agriculture).

We should tell the banks that we now own to restore short-term trade credits.

We should spend aid on empowering women in developing countries which, all the evidence shows, is the biggest key to reducing world hunger.

Will any of this happen?

Certainly not if we don't pressurise our governments. And not just before the UN's World Food Summit in three weeks but also before the world trade ministers gathering next month and the Copenhagen UN climate change conference in December.

The world produces enough grain to provide each one of its inhabitants with 2,500 calories a day. What is missing is the political will to ensure its fair distribution. The predictions are that between 200,000 and 400,000 more children could die every year if the poor nations' food crisis goes unaddressed.

A world which found trillions to bail out the banks ought to be able to scrape together the resources to do something to prevent that. If we do not, our children will one day look back with incredulity and ask us why we did nothing.

Are hundreds of thousands more children destined to starve to death?

Yes...

* Emerging economies are demanding more of the world's food – leaving less for the very poor

* Demand for biofuels will keep cereal prices high – making staples beyond the reach of the poorest

* Climate change will make things worse, reducing farm production by as much as 60 per cent in parts of Africa

No...

* Not if we boost investment and aid for agriculture training, irrigation, modern machinery and roads

* Not if we reform trade policy to enable poor farmers to sell to the West without huge tariffs

* Not if we stop the West's farmers dumping produce on the developing world, thus destroying local markets