  We re-examine past suggestions of a close link between terrestrial climate
change and the Sun's transit of spiral arms in its path through the Milky Way
galaxy. These links produced concrete fits, deriving the unknown spiral pattern
speed from terrestrial climate correlations. We test these fits against new
data on spiral structure based on CO data that does not make simplifying
assumptions about symmetry and circular rotation. If we compare the times of
these transits to changes in the climate of Earth, not only do the claimed
correlations disappear, but also we find that they cannot be resurrected for
any reasonable pattern speed.
