Although fuel can never score over food in the  hierarchy of needs, modern society essentially needs both to survive. Sourya Biswas reports

Would you prefer food for an empty stomach or fuel for your empty car? The question seems to be a no-brainer, and similar arguments have been advanced by the pro-food brigade who contend that energy-crop programmes compete with food crops in a number of ways (agricultural, rural investment, infrastructure, water, fertilizers, skilled labour etc.) and thus cause food shortages and price increases.

In fact, UN the special rapporteur on the right to food Jean Ziegler had gone on record decrying biofuels as a ''crime against humanity''. Even World Bank President Robert Zoellick had accused demand for ethanol as a "significant contributor" to soaring food prices around the world earlier this year.

However, arguments from the opposing side have been no less persuasive. From asserting that the world economy needs to switch to a greener alternative to the polluting and fast-depleting fossil fuels, to arguing that foodgrain shortages were caused by macroeconomic factors like droughts and escalating oil prices, the ethanol club has stood steadfast behind its cause and lobbied hard against reversing existing government incentives. The truth, as often is the case in such contentious matters, lies somewhere in between.

Food prices did rise atrociously high earlier this year, fuelled by decreased production and increased demand. And diversion of agricultural land from food crops to biomass did contribute to this shortage. However, this impact was definitely not the decisive factor, as some from the pro-food group would like us to behave. The gradual decrease in prices over the last few months is ample proof of that.

There were several factors behind the initial rise, with the two main reasons being decrease in worldwide foodgrain production due to climatic setbacks, and galloping inflation fuelled by increased oil prices. Russia, the Ukraine, Northern Europe, Argentina, Australia and other parts of the world experienced reduced crop production in 2007, due to drought, early frost and other crop problems.

This was the second year in a row of drought and reduced crop yields in many of these countries. There was a reduction in total global grain and oilseed production in 2006, and again in 2007. This was only the third time in past 37 years that global production has dropped two consecutive years.

Also, fuel prices ballooned over the last two years. From $20 a barrel in 2006, crude went up to $140 a barrel in 2008. In a testament to the fact that the world economy runs on oil, prices of every commodity, including food, increased.

In a related argument, it has been calculated that only about 20 per cent of every consumer dollar spent on food in the US goes to the producer for the raw food product. The other 80 per cent is for the off-farm costs of food such as labour, marketing, processing, wholesaling, distributing and retailing. Based on a 2007 study, rising oil prices had more than twice the impact on retail food prices, compared to a comparable increase in corn prices.

Even though the above ratios are highly skewed in favour of the latter category in developed countries, the economic costs of high fuel prices on food cannot be completely discounted even in poorer nations.

Pro-food and pro-fuel clash
A lot of the food versus fuel debate has centred on corn production in the US. The country's biofuels industry plans on producing record amounts of ethanol this year to meet a mandate of the new US energy law - and is using a lot of corn to do it. Hence, they were regarded as driving up food prices, especially as the price of corn doubled in two years to $6-7 per bushel in July. However, with the price now more than halved within five months, their contributions towards increased food prices is being questioned.

Amidst all this bickering between the pro-food and pro-fuel groups, some researchers have sought middle ground. While they discourage converting arable land from growing foodgrains to biomass, in fact discourage using corn as a source of ethanol altogether, they do not dismiss ethanol from biomass as a newfangled discovery. In fact, they propose a much more efficient way of obtaining fuel from plants - by processing cellulose instead of corn.

On a blackboard, it looks so simple: Take a plant and extract the cellulose. Add some enzymes and convert the cellulose molecules into sugars. Ferment the sugar into alcohol. Then distill the alcohol into fuel. One, two, three, four - and we're powering our cars with lawn cuttings, wood chips, and prairie grasses instead of costly oil.

Unfortunately, passing chemistry doesn't mean acing economics. Scientists have long known how to turn trees into ethanol, but doing it profitably is another matter. We can run our cars on lawn cuttings today; we just can't do it at a price people are willing to pay.

The problem is cellulose. Found in plant cell walls, it's the most abundant naturally occurring organic molecule on the planet, a potentially limitless source of energy.

But it's a tough molecule to break down. Bacteria and other microorganisms use specialized enzymes to do the job, scouring lawns, fields, and forest floors, hunting out cellulose and dining on it.

Evolution has given other animals elegant ways to do the same: Cows, goats, and deer maintain a special stomach full of bugs to digest the molecule; termites harbour hundreds of unique microorganisms in their guts that help them process it. For scientists, though, figuring out how to convert cellulose into a usable form on a budget driven by fuel prices has been neither elegant nor easy. To tap that potential energy, they're harnessing nature's tools, tweaking them in the lab to make them work much faster than nature intended.

Cellulosic ethanol, in theory, is a much better bet than corn-sourced ethanol. Most of the plant species suitable for producing this kind of ethanol - like switchgrass, a fast- growing plant found throughout the world, and farmed poplar trees - aren't food crops. And according to a joint study by the US Departments of Agriculture and Energy, it's possible to grow more than 1 billion tons of such biomass on available farmland, using minimal fertilizer.

And freshwater-consuming switchgrass isn't the only alternative. Saltwater-loving plants could open up half a million square miles of previously unusable territory for energy crops, helping settle the heated food-versus-fuel debate. While growing crops in saltwater has been on the fringes of horticulture for decades, the new demand for alternative energy has pushed the idea onto the pages of the nation's most prestigious scientific journal and drawn the attention of NASA scientists.

Citing the work of Robert Glenn, a plant biologist at the University of Arizona, two biologists argue in the latest issue of journal Science that "the increasing demand for agricultural products and the spread of salinity now make this concept worth serious consideration and investment."

Where is the land going to come from
The world's population has grown by five billion people since 1900 to an astounding 6.7 billion today. Despite the population explosion, food production - primarily animal feed and commodity cereals like wheat and rice - has been able to keep pace. But the food system has been severely stressed by a variety of factors, including the increasing use of arable land to grow energy crops to turn into biofuels.

Even if energy crops didn't cause all or even most of the precipitous rise in food prices in 2007, most social and environmental groups agree that the best location for bio-energy crops would be on currently unusable land. That would ensure that land used to grow food crops in poor countries wasn't converted to growing energy crops to power cars in developed nations.

The million-dollar question is: where to get all this land, and what to grow there? Overly salty land could play a large and previously underappreciated role. That's because there's plenty of previously uncultivated territory in the world's coastal deserts, inland salty soils, and over-salinized agricultural land. As for the second part of the question, certain plants called halophytes thrive in saltwater. While salt damages most plants, these salt-loving plants actually use the saltwater to draw in fresh water. In essence, they make themselves saltier than the surrounding water, which, through osmosis, drives fresh water into the plant.

These plants are attractive candidates for both food and fuel because they have very high biomass and oil seed yields. The Science authors note that one leading halophyte-candidate, Salicornia bigelovii, produces 1.7 times more oil per acre than sunflowers, a common source of vegetable oil.

Thus the need of the hour is not to derail the biofuel industry by reversing earlier energy mandates and government incentives, but to encourage research for commercial use of biomass-sourced ethanol. While corn for food definitely scores over corn for fuel, the growth in biofuel technology should not be allowed to go to waste.

Although fuel can never score over food in the  hierarchy of needs, our modern society essentially needs both to survive. And fossil fuel reserves are depleting by the day.