ABSTRACT
The natural climate is characterized by enormous amounts of chaotic variability that we experience as weather on short time scales and as year-to-year (and longer) differences in climate characteristics. Not only do we experience variations in temperature, precipitation, wind speed and so on within the course of a few days, but we also experience a summer, for example, that may be warm or cool, dry or wet, or be otherwise distinguished from other summers. This natural chaotic variability is driven by the energy from the Sun, which is absorbed by the Earth and re-emitted to space in the form of heat. Much of the weather and climate variability we experience results from the transfer of energy from places where it is absorbed to places where it is ultimately radiated back to space. This variability occurs spontaneously, and would occur even in the absence of any external influences on the climate, such as that from volcanic eruptions. Thus climate scientists often refer to this variability as natural internal climate variability.
