Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most profound problems associated with climate change.

A reconstruction of global surface temperature is used to show that deglacial temperature is correlated with and generally lags carbon dioxide concentration, a result that contributes to the explanation of the temperature change that occurred at the end of the most recent ice age.