Isotope sediment dating memberlist phpmode
Internal forcing mechanisms are natural processes within the climate system itself (e.g., the meridional overturning circulation).
Slight variations in Earth's orbit lead to changes in the seasonal distribution of sunlight reaching the Earth's surface and how it is distributed across the globe.
Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast (e.g., a sudden cooling due to airborne volcanic ash reflecting sunlight), slow (e.g.
thermal expansion of warming ocean water), or a combination (e.g., sudden loss of albedo in the arctic ocean as sea ice melts, followed by more gradual thermal expansion of the water).
However, there is evidence for the presence of water on the early Earth, in the Hadean Over the following approximately 4 billion years, the energy output of the sun increased and atmospheric composition changed.
The Great Oxygenation Event -oxygenation of the atmosphere- around 2.4 billion years ago was the most notable alteration.