Vostok core

The Vostok core is an Antarctic ice core which shows that as temperature went up and down over the last 250,000 years, carbon dioxide also went up and down.

* In fact, in early 1999, there was a paper in Science in which they have now gotten adequate resolution so they can measure which came first, the temperature change or the carbon dioxide change. And guess what? The temperature change came first, followed by the carbon dioxide change about 600 years later. This means that something changed the temperature, not the carbon dioxide. But then as the climate warmed, more carbon dioxide apparently was released from the ocean into the atmosphere. [1]