The public debate about global warming has been polluted with politics and partisanship. Is there any issue more discussed—but less debated in recent years?

This video sets aside doomsday alarmism and political axe-grinding to look at the science behind the history of climate change on earth. An examination of early Viking colonies on Greenland, wiped out by a period of global cooling, enables scientists to draw important conclusions about our current phase in the climate cycle. What we learn in this program is that earth’s climate is always changing—from The Middle Ages and the "Little Ice Age" to the modern warming that has been going on since 1850—well before human-generated CO2 began increasing in our atmosphere.

Dr. Willie Soon of the Harvard-Smithsonian Center for Astrophysics and Dr. David Legates of the University of Delaware provide an easy-to-follow review of current climate science, which suggests that the sun's irregular patterns and other natural forces are the major sources of climate change.