The water-food-energy nexus is a complex concept that is frequently cited but rarely fully understood. However the cost of failing to grasp these connections is measured not only in money, but in human lives.

The impact of extreme droughts on major agricultural production areas, such as those currently affecting the United States, is a stark reminder of this link. Water, which is vital for food, will be less available if food is used to produce fuel instead.

According to a study of the US Department of Energy, up to 9,100 litres of water are required to produce one litre of biodiesel. Add this to the structural overuse of freshwater and temporary drought affecting crops and food prices. The result is clear that biofuel production has had a massive impact on the increasingly fragile water-for-food equation and on the livelihoods of the most vulnerable people in the world.

The problem is enhanced by the fact that 40% of corn production in the United States now goes towards ethanol , a percentage that will increase to nearly 50% during a year of drought in the cornbelt due to rigid mandates. Meanwhile in Europe, it was recently reported that 60% of rape is being used for fuel production (Javier Blas, Financial Times August 12, quoting FAO).

We saw the consequences of this already happening in 2008 and 2010; now further millions of people are pushed into poverty and famine. Precisely how many is now hard to say since FAO data estimating the number of people going hungry to bed has stopped – apparently for technical reasons.

Looking at the bigger picture, this is self-defeating. Proposing biofuels as an apparent solution to one crisis, such as climate change, in fact deepens the effects of two others, namely water and food security.

Last week, Germany’s Development Minister Dirk Niebel called for biofuel containing corn to be banned from the country’s petrol pumps.  Mr Niebel deserves our full support. And we should go beyond Germany in this demand: removing subsidies and all mandates for biofuels, and in consequence putting a complete stop to food for fuel.