The climate system is complex because it is made up of several compartments (e.g. atmosphere, oceans, ice caps, etc.), each with its own specific response time and thermodynamic properties. What's more, these elements
these elements interact with each other in non-linear ways, and are connected to other complex systems such as the carbon cycle, which regulates the concentrations of certain greenhouse gases in the atmosphere. The
climate can be disrupted by different types of external causes (e.g. changes in insolation) acting at different spatial and temporal scales within the system. An additional problem is that internal rearrangements, resonances and oscillations can occur, making it even more difficult to determine a state of equilibrium.
Ultimately, our climate is characterized by considerable natural variability, and true long-term trends are not always easy to distinguish from transient fluctuations.
Lecture