 When experts talk about the coming food security crisis, the date they fixate upon is 2030. By then, our numbers will be nudging 9 billion and we will need to be producing 50% more food than we are now.  By the middle of that decade, therefore, we will either all be starving, and fighting wars over resources, or our global food supply will have changed radically. The bitter reality is that it will probably be a mixture of both.  Developed countries such as the UK are likely, for the most part, to have attempted to pull up the drawbridge, increasing national production and reducing our reliance on imports.  In response to increasing prices, some of us may well have reduced our consumption of meat, the raising of which is a notoriously inefficient use of grain. This will probably create a food underclass, surviving on a carb- and fat-heavy diet, while those with money scarf the protein.  The developing world, meanwhile, will work to bridge the food gap by embracing the promise of biotechnology which the middle classes in the developed world will have assumed that they had the luxury to reject. In truth, any of the imported grain that we do consume will come from genetically modified crops. as climate change lays waste to the productive fields of southern Europe and north africa, more water-efficient strains of corn, wheat and barley will be pressed into service; likewise, to the north, Russia will become a global food superpower as the same climate change opens up the once frozen and massive Siberian prairie to food production.  The consensus now is that the planet does have the wherewithal to feed that huge number of people. It's just that some people in the west may find the methods used to do so unappetising.  Jay Rayner  TV presenter and the Observer's food critic