Cooling a warming cycles appear to have been caused by cyclic changes in the ellipticity of the earth's orbit about the sun, together with changes in the tilt of the earth's rotational axis and the degree of wobble of the rotational axis.
(Cooling a warming cycles; appear; ) (Cooling a warming cycles; to have been caused; by cyclic changes in the ellipticity of the earth's orbit)
Cooling a warming cycles Cooling a warming cycles
appear to have been caused
by cyclic changes in the ellipticity of the earth's orbit