Recent considerations on climatic variations are reviewed and following points are summarized, (1) Distribution, influences on human society and causes of climatic variations is dependents of time scale of climatic variation. (2) Climatic system is composed of various elements and climatic status determined by delicate balance of these elements. (3) Increase of human consumption of fossil fuel brings increase of CO2 in the atmosphere. If such trends continues, marked change of climate will occur on the middle of next centuries.
