Causation

Correlation alone does not establish causation. Two quantities might change together because one causes the other, because another factor affects both, or by coincidence. Natural climate variation can also influence temperature over shorter periods.

Correlation alone does not demonstrate causation. Two variables could rise together by coincidence, one might cause the other, or both might be affected by a third factor. Fossil-fuel consumption and carbon dioxide concentration therefore provide important evidence, but a strong evaluation must consider the other links in the causal explanation.