Julian Cribb discussed the limitations to the world food supply which could result in worldwide famine by mid-century. If we don't reinvent agricultural science, we could see severe famines even within 20-30 years, he reported. Increased flooding and droughts will cause crop failures and this will drive up the price of grain and food. With such famines, we'll also see "tidal movements of refugees" looking for food, he said, and this could destabilize various countries. Water shortages are also going to be a huge problem, if we don't start working on alternatives now, such as desalination plants.