Natural variability refers to the inherent and spontaneous fluctuations in natural systems that occur due to internal processes or external factors. It is a fundamental aspect of all complex, non-linear systems, including Earth's climate system. Natural variability can manifest as short-term weather patterns, seasonal changes, or long-term trends over decades and centuries. Understanding natural variability is essential for predicting future climate conditions and distinguishing human-induced changes from the inherent behavior of our planet's atmosphere and oceans.