The Earth’ climate is a complex system consisting of the atmosphere, the ocean and the land surface. This system receives energy from the sun. Latitudinal variations in insolation and the rotation of the Earth lead to a complex turbulent geophysical flow which induces important transports of heat and mass. Part of the solar radiation is reflected, the rest is radiated as long wave radiation. The radiative balance is complicated by atmospheric water vapour and other trace gases, clouds, heat transport and other factors.