What part of the earth are we talking about?


"Climate system" where the global energy and water cycle takes place
Horizontal scale: The whole globe (1/4 circumference = 10^7 m)
Vertical scale (cf. radius of the earth ~ 6400 km)
Atmosphere (non-ionized ~ 80 km; "lower atmosphere", ~ 20 km)
Ocean (maximum depth ~ 10 km)
Ice and snow (maximum depth of ice sheet ~  4 km)
Land "sufrace" (annual energy storage O(1 m); groundwater O(1 km)