Natural variability in the climate system is broadly categorized into two main types, based on whether the factors influencing the climate originate from outside or within the climate system itself.
According to the provided information, there are two types of natural variability: those external and internal to the climate system.
External Variability
External variability refers to changes driven by factors outside the Earth's climate system. These factors influence the energy balance of the planet.
Based on the reference, examples of external controls on climate variability include:
- Variations in the sun: Changes in solar radiation output directly affect the amount of energy reaching Earth.
- Volcanic eruptions: Large volcanic eruptions can inject aerosols and gases into the atmosphere, temporarily altering Earth's radiation balance.
- Changes in the orbit of the Earth around the sun: Long-term cycles in Earth's orbit, axial tilt, and wobble (known as Milankovitch cycles) affect the distribution and intensity of solar radiation received by different parts of the Earth over thousands of years.
Internal Variability
Internal variability encompasses fluctuations that originate from within the climate system itself. These are interactions between components such as the atmosphere, ocean, land surface, and ice.
While the reference does not provide specific examples of internal variability, it identifies it as the second primary type alongside external variability.
Summary Table
Here is a simple overview of the two types of natural variability:
| Type | Description | Examples (from reference) |
|---|---|---|
| External | Caused by factors outside the climate system | Variations in the sun, Volcanic eruptions, Earth's orbital changes |
| Internal | Caused by interactions within the climate system | (Examples not provided in the reference) |
Understanding these distinct types of natural variability is crucial for differentiating them from other influences on climate, such as human-caused changes.
