Climate as a game of chance

We use general concepts and simple models to examine the role of randomness in chaotic systems, like Earth's climate, in response to external forcing. The response of a simple homogeneous system is determined by its correlation function in accordance with the fluctuation–dissipation theorem. A structured (patterned) system responds in a more complicated way. Whereas its mean state (for example, Earth's global temperature) is changing only slightly, extreme events (such as floods and droughts) are increasing more dramatically in number. The statistics of extremes reveals remarkable properties, in particular, clustering (troubles never come alone, the saying goes) and are here illustrated by precipitation and space climate processes.