What are the primary forcings of the Earth system? - NASA Science
According to scientists' models of Earth's orbit and orientation toward the Sun indicate that our world should be just beginning to enter a new period of cooling -- perhaps the next ice age.[Via Tucson Citizen]
However, a new force for change has arisen: humans...
Other important forcings of Earth's climate system include such "variables" as clouds, airborne particulate matter, and surface brightness. Each of these varying features of Earth's environment has the capacity to exceed the warming influence of greenhouse gases and cause our world to cool.