Global climate change, often simply referred to as "global warming," is a complex and scientifically controversial issue that attributes an increase in the average annual surface temperature of Earth to increased concentrations of carbon dioxide and other gases in the atmosphere (air surrounding Earth). Many scientists disagree on how to best interpret data related to climate change. Scientists also argue about which data (for example, measurements of changes of thickness in arctic ice, measurements of sea temperatures at critical locations, or measurements of certain chemicals in the atmosphere, etc.) should be used to make informed decisions about the extent and rate of global climate change.

Climate describes the long-term conditions or average weather for a region. Throughout Earth's history, there have been dramatic and cyclic changes (changes that repeat themselves in cycles that can last from thousands to millions of years) in climatic weather...