The climate
change in this period is generally believed to be associated with precessional
changes in the distribution of
solar radiation, which primarily affect land - sea temperature contrast, and
give only a regional warming, plus an enhancement of certain monsoonal circulations.
Refraction, specifically the real component of refraction n (describes bending of rays, wavelength
changes relative to a vacuum, affects blackbody fluxes and intensities — as opposed to the imaginary component, which is related to absorption and emission) is relatively unimportant to shaping radiant fluxes through the atmosphere on Earth (except on the small scale processes where it (along with difraction, reflection)
gives rise to scattering, particularly of
solar radiation —
in that case, the effect on the larger scale can be described by scattering properties, the emergent behavior).