Why is the concept of climate forcing critical to understanding the causes of global climate change? ...

Climate forcing is the amount of change in thermal energy units (watts/square meter on Earth's surface) caused by a given factor. This allows a quantitative scientific evaluation of the many variables that make up the equation of Earth's energy balance. The variables include solar output, ocean absorption, ocean circulation, changes in albedo, Milankovitch cycles, aerosols, and human-caused factors such as increased concentrations of such greenhouse gases as carbon dioxide and CFCs. Positive values indicate a warming effect, while negative values have a cooling effect. This analytical approach strengthens the scientific conclusions drawn about the relative importance of each variable contributing to climate change.