Continue exploring the relationship between carbon dioxide and temperature trends in the Climate Trends learning tool.

Question: Throughout the historical record, CO₂ and temperature are closely linked. Can you determine whether one factor is responding to the other? Do changes in one factor consistently cause changes in the other?

Look at the historical patterns of temperature and CO₂ and try to determine which factor begins to change first. For example, if CO₂ concentrations consistently increase before temperature, we can conclude that CO₂ changes may cause temperature changes.

Let's focus on a few historical changes. Between 138,000 and 126,000 years before present (YBP), temperature changes preceded changes in CO₂ levels. This suggests that temperature changes caused changes in CO₂ concentration. On the other hand, between 340,000 and 323,000 YBP, CO₂ increases preceded changes in temperature.

One factor has not consistently changed before the other; we can conclude that the two factors are linked, but we cannot determine causation.