Introduction
We have reviewed the scientific consensus on how the chemistry of
the atmosphere is changing. We also have estimated future changes in
atmospheric composition. And most recently, we have reviewed calculations
of the change in radiative forcing that will result from various policy
scenarios on energy generation and regulation of other sources of
greenhouse gases. Now we take the next step and translate these changes in
radiative forcing into changes in climate of the earth. We first examine
what we mean by climate change.