Anthropogenic Global Warming, or just natural variation?

For the past 1.3 million years there have been 13 ice ages, average duration 90,000 years, and each followed by an interglacial period, average duration 10,000 years. During both ice ages and interglacial periods, there will be numerous briefer cycles of warming and cooling. A 65 million year review of climate and related information is [...]