I don't know well if I'm too optimistic on our science and technology, but I think that the earth will be able to produce enough food to support the human race. They predicted, in 2050, there will be 9 billion people in the whole world. And the great increase will be in developing countries. Then, the world will get involved in food crisis.
Yes, the ground or the fields might not be enough to produce crops in quality and quantity in order to feed all people on earth, but what we have is developing technology. We already have many kinds of GMF (Genetically Modified Food). For example, there is vegetation which is similar with an original potato, but can be grown in the dry area lika Africa. Also, we can see many results of efforts to modify food in a better size and nutrition, such as Super Corn.
Besides, what we can bet our hope are the associations fighting against hunger. WFP, World Food Programme, is working to help prevent hunger in the future. They use food as a means to build assets, spread knowledge and nurture stronger, more dynamic communities. Aside from it, there are many associations fighting against hunger now and for future ─ ONE, which fights extreme poverty, ActionAid International, which works for helping poor people own power to fight poverty.
If we are aware of the crisis and participate in the projects that help the poor, study methods to survive in the future, and accumulate money for it by our concern and sympathy, there is a way, definitely.