Gore also uses an argument that the correlation between carbon dioxide concentration and temperature in ice core records from the distant past, as shown in Figure 3, demonstrates that carbon dioxide and temperature are strongly related.However, a statistical correlation between two variables doesn't determine which one is causing the relationship and which one is responding.The temperature increases between about 18, and then decreases for a 30-year period from 1940 to 1970, after which it begins to climb again.This is very peculiar if carbon dioxide is driving global temperature, because the greatest increase in output from industrial production and the associated release of carbon dioxide would have occurred during this period.In fact, they normally show a 400-year-long warm period from about 1000 to 1400 A.
These changes in temperature associated with sunspot number suggest that the sun may influence the climate over millennial cycles.
Figure 1 seems to provide compelling evidence that global warming is caused by an increase in carbon dioxide.
The sudden steep rise in temperature following a long period of uniform temperature prior to the Industrial Age seems to be inextricably linked to man's activities since 1850 or so.
This figure shows a superposition of average global temperature curves obtained by different research groups using different data and/or methodologies.
For example, the red curve shows the results obtained by Moberg et al, The average temperature in the "handle" of the hockey stick over the period from about 1000 to 1850 A. remains relatively uniform, followed by a sudden rise in the "blade" since 1850, supposedly following the recent increase in carbon dioxide.