In fact, the world food production is sufficient to feed the 7+ billion population that we have currently. The reason one hears about food shortages is mainly because of the inefficient distribution and poor storage of food. In the developed countries, food waste is also a major consideration. A bit more co-operation among nations and some good planning can solve the global food crisis just now. This statement, however, does not diminish the urgency of planning for a sustainable food supply for the future - and controlling population growth is the most important step one can take.
Water shortage is more difficult to manage as it is not possible to transport water from areas of plenty to water-stressed regions. Climate change with rising global temperatures will make some areas almost impossible to manage. When the glaciers melt and are gone on top of mountains, rivers feeding the plains will run dry. With ground water already dangerously depleted in most area of the world, it is difficult to see how the ever-increasing demands will be met.
New technologies can help but whether they will be there in time to avoid serious catastrophes - we do not know. I shall discuss these in future publications.
In the following I publish the slides of my 2012 talk in Glasgow.