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Past and future Milankovitch cycles. VSOP allows prediction of past and future orbital parameters with great accuracy.
Figure shows variations in orbital elements:
Obliquity (axial tilt) (ε).
Eccentricity (e).
Longitude of perihelion (sin(ϖ) ).
Precession index (e sin(ϖ) ), which together with obliquity, controls the seasonal cycle of insolation.[1]
Calculated daily-averaged insolation at the top of the atmosphere ({\displaystyle {\overline {Q}}^{\mathrm {day} }}),![]()
on the day of the summer solstice at 65° N latitude.
Two distinct proxies for past global sea level and temperature, from ocean sediment and Antarctic ice respectively are:
Benthic forams
Vostok ice core
The vertical gray line shows current conditions, at 2 ky A.D.