In recent years climate change and its impacts have become a separate field of inquiry. Climate-related risks to food security, water supply, biodiversity and human health are expected to increase with further global warming. The purpose of this study is to show how the definition of food security in particular has changed in times of climate change. It is a multidimensional phenomenon that has no legal definition so far. Associated mainly with physical access to food, food security was identified as a global problem by Food and Agriculture Organization (FAO) in 1975 at the Word Food Conference. At the European Union level, food security is strictly connected with the Common Agriculture Policy. One of the new aims of that policy is to make agriculture more sustainable and responsive to current and future challenges, including climate variability. There is the dual challenge of both adapting production systems to new conditions and reducing greenhouse gases produced by agriculture.