Humans are live beings. In order to live they need food. Disposing of creative mind Homo sapiens became the top consumer in the trophic chain on the Earth and multiplied faster than their food. Then people have started to cultivate plants and to breed animals to ensure their food. Their struggle for life developed inside human species and conducted to wars which became more and more destructive. The last two World Wars were tremendously hard. So the United Nations’ Organization disposing of a Security Council has been made up to secure people against new World Wars. But recognizing that lack of food stays at the wars’ origins ONU included a special Food and Agriculture Organization (FAO), dedicated to secure people against famine anywhere on the Earth. On the above basis, the present paper trays to explain scientifically, the importance of farm animal biodiversity for the food security of the world. How FAO acted to sustain farm animal biodiversity is exposed, as well. Some controversial questions and misunderstanding concerning relations between environment protection especially referring to the Earth’s global heating and farm animal biodiversity are answered, too. At the end opinions and hopes related to the contributions of the future Conference on the Sustainable Development that will have place in June of the next year and the food security of the World are emphasized. The final conclusions are: natural animal biodiversity secures the biological balance on the Earth; farm animal artificial biodiversity helps human food security and the social sustainability.