 Climate variability

Climate variability is variation in climate statistics across time or space, including fluctuations in means, seasonal behavior and extremes. It can arise internally from interacting atmospheric and oceanic dynamics or from changing external influences. The averaging interval and variable being measured must be specified.

A climate system can fluctuate even under steady forcing. A nonlinear convection model can produce nonperiodic behavior without a random external input, illustrating one mechanism for internally generated variability. This does not identify the cause of a particular observed climate trend: attribution requires comparing mechanisms, timescales and independent observations.^[ref]