text: For Fahad bin Mohammed Al-Attiya, it is the nightmare scenario. He is the executive chairman of the Qatar National Food Security Programme.
  The small Gulf state is 100% dependent on desalinated water.
  Mr Al-Attiya says such a scenario would threaten the very survival of Qatar and its population of more than two million.
  "We need to have clean water," he says. "A situation like the Gulf of Mexico where BP lost two or three million barrels of oil - if that happens in the [Persian] Gulf the consequences would be severely different."
  Qatar sits on the world's third largest gas field and is investing billions into mega-reservoirs at home to give it some kind of water security.
  But water is not the only problem. Despite being the richest country per capita in the world, Qatar also needs to import 90% of its food.
  "Qatar is... hydrocarbon-rich," said Mr Al-Attiya, speaking on a special In the Balance discussion on food security for the BBC World Service. "But certainly water-poor and food-poor.
  "Not only that, but for our own development we have to import the... labour to develop our country so we need to import even further to feed the nation."
  Where the solution to water security is largely domestic, food security involves a tangle of trade, diplomatic and political issues.
  Qatar joins a growing list of countries that includes other Gulf states, India, China and South Korea, that are not just importing food but buying the land abroad on which it is grown.
  These countries are often accused of "land grabs" - the buying up of millions of hectares of overseas agricultural land with scant regard for the livelihoods of local farmers or the environment.
  The charity Oxfam claims land eight times the size of the UK was sold off globally in the last decade, enough to grow food for a billion people.
  It says that more than 60% of investments in agricultural land by foreign investors between 2000 and 2010 were in developing countries with serious hunger problems.
  Two-thirds of those investors plan to export everything they produce on that land.
  But the truth is, for all its wealth, an investor like Qatar can itself be at the mercy of global weather, disease and politics.
  The price Qatar pays for losing imports is not just financial - it is often the physical loss of food to eat.
  Mr Al-Attiya points out that many of Qatar's trading relationships fell apart in 2010 when India, Russia and other countries blocked exports in the face of the worst droughts in a century. "That made countries like ours question how much faith we put in free trade."
  So he says that Qatar has to have a bigger vision. "We will not go in and invest simply to service our population of 2.5 million people.  It doesn't make any economic sense.
  "We will go in and invest to service the country, and the region - and the globe at large.
  "I say there is no direct link between investment in a foreign country and food security of the country that made that investment.
  "Because the country that received that investment is a sovereign state and it could say, 'Thanks for the investment but in times of crisis I am not going to export that food.' What we do... is really enhancing the availability of a food at a global level."
  Such a global perspective is not the norm. Land grabs get bad press - for good reasons.
  Ahmed Soliman, research assistant on the Horn of Africa at Chatham House, says land grabs put pressure on local communities. "Many of the populations are involved in either subsistence agriculture or very low-level agriculture.
  "Taking into consideration what is sustainable for them in terms of how they are able to feed their families and future generations is very important. And when it gets down to national level those concerns are not being met."
  But there may be ways of meeting them.
  Prof Jacqueline McGlade, chief scientist of the UN Environment Programme, says: "The kind of investments the Qataris are talking about is a very 'soft' power, because they are talking about raising the whole global food production system.
  "But in a more aggressive world perhaps there is space for an investment bond that says if things go horribly wrong and you have denuded the land we're going to use that fund to reinstate some kind of productive farming."
  But there is also a need for a relationship between investor and host country that works day-to-day as well as in a crisis.
  "It's a very complex problem," says Ken Ash, director of trade and agriculture at the Organisation for Economic Co-operation and Development (OECD).
  "People are hungry because they are poor, because they don't have money to buy food when they need it. It isn't just about producing more grain or more rice. It's about generating income opportunities in rural areas so that people can increasingly feed themselves."
  The question of food security could have some very prosaic solutions. For Prof McGlade it is a question of too much waste. "It's waste at the farm level, it's waste through the supply chains and delivery, and the lack of refrigeration.
  "You look under just one tarpaulin and you see the extreme loss of potential at every stage of the food supply. So if we can tackle food waste at the very beginning then I think food security becomes something that is realisable."
  In the Balance's discussion on food security is broadcast at 08:30 GMT on Saturday, 6 December on BBC World Service.
target: Imagine this: an oil spill the size of the Gulf of Mexico 2010 disaster, but this time in the Persian Gulf.