In the past, these traits have been particularly useful at helping birds and mammals disperse around the world during periods of global cooling, the researchers point out, including a major cooling episode that occurred around 34 million years ago. (scientificamerican.com)
The recent period of global cooling does not itself disprove the greenhouse effect. (conservativehome.blogs.com)
Periods of weak solar cycles are associated with periods of global cooling. (notrickszone.com)