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δ 18 O, a proxy for temperature, for the last 600,000 years (an average from several deep sea sediment carbonate samples) [a]. The 100,000-year problem (also 100 ky problem or 100 ka problem) of the Milankovitch theory of orbital forcing refers to a discrepancy between the reconstructed geologic temperature record and the reconstructed amount of incoming solar radiation, or insolation over ...
Milankovitch studied changes in these movements of the Earth, which alter the amount and location of solar radiation reaching the Earth. This is known as solar forcing (an example of radiative forcing). Milankovitch emphasized the changes experienced at 65° north due to the great amount of land at that latitude.
Orbital forcing is the effect on climate of slow changes in the tilt of the Earth's axis and shape of the Earth's orbit around the Sun (see Milankovitch cycles).These orbital changes modify the total amount of sunlight reaching the Earth by up to 25% at mid-latitudes (from 400 to 500 W/(m 2) at latitudes of 60 degrees).
[17] [18] [10] At this point, when ~25% more of Antarctica's surface was above sea level and able to support land-based ice sheets relative to today, [19] CO 2 levels had dropped to 750 ppm. [20] This was the beginning of the Late Cenozoic Ice Age. This was when the ice sheets reached the ocean, [21] the defining point. [22]
The second contribution is the explanation of Earth's long-term climate changes caused by changes in the position of the Earth in comparison to the Sun, now known as Milankovitch cycles. This partly explained the ice ages occurring in the geological past of the Earth, as well as the climate changes on the Earth which can be expected in the future.
In chemistry, a chemical oscillator is a complex mixture of reacting chemical compounds in which the concentration of one or more components exhibits periodic changes. They are a class of reactions that serve as an example of non-equilibrium thermodynamics with far-from-equilibrium behavior.
Five million years of glacial cycles are shown, based on oxygen isotope ratio believed to be a good proxy of global ice volume. The MPT is the transition between the periodicities shown in green. The Mid-Pleistocene Transition ( MPT ), also known as the Mid-Pleistocene Revolution ( MPR ), [ 1 ] is a fundamental change in the behaviour of ...
The snowball Earth hypothesis was originally devised to explain geological evidence for the apparent presence of glaciers at tropical latitudes. [15] According to modelling, an ice–albedo feedback would result in glacial ice rapidly advancing to the equator once the glaciers spread to within 25° [ 16 ] to 30° [ 17 ] of the equator.