Global warming, as used in the popular context, is a scientifically controversial phenomenon that attributes an increase in the average annual surface temperature of Earth to increased atmospheric concentrations of carbon dioxide and other gases. Global warming describes only one of several components involved in climate change and specifically refers to a warming of Earth's surface outside of the range of normal fluctuations that have occurred throughout Earth's history.

Climate describes the long-term meteorological conditions or average weather for a region. Throughout Earth's history there have been dramatic and cyclic changes in climatic weather patterns corresponding to cycles of glacial advance and retreat that occur on the scale of 100,000 years. Within these larger cycles are shorter duration warming and cooling trends that last from 20,000 to 40,000 years. Scientists estimate that approximately 10,000 years have elapsed since the end of the last ice age, and examination of physical and...