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Figure 1: Orbital paramters tilt,
eccentricity, and precession
(Not to scale).
Changes to Earth’s orbit alter
the distribution of sunlight between the northern and southern hemispheres. Understanding the effect of
subtle shifts in this energy distribution gives clues to how sensitive Earth’s climate is to small, gradual changes.
Tilt is easy for anyone to observe, as it is primary driver of seasons and of the changes of the sun and moon.
For climate, the degree of tilt determines how extreme the difference between seasons can be. For example,
in Figure 2, the two worlds may have the same sun and the same orbit, but would have drastically different
seasons because of the differences in tilt:
Figure: Right- Earth today with a hypothetical Earth having a 90 degree tilt (not to scale)
ICY SCIENCE | QTR 1 2014