Don’t increases in temperature lead to increases in CO2, not the other way around?
Yes and no. Increases in global temperature can lead to an increase in atmospheric levels of CO2. However, as CO2 is added to the atmosphere, it traps additional heat causing a further rise in global temperatures.
Source: U.S. EPA
As you can see from the graph above, historically temperature and CO2 levels have very closely mirrored one another. As one rises or falls, the other follows suit. Skeptics of anthropogenic global warming point out that historically, temperature has risen first followed by CO2, so, they conclude, CO2 does not cause a rise in temperature. However, the proper conclusion is that, historically, CO2 has not typically been the initiator of temperature change but rather a subsequent contributor to it.
As a result of changes in the Earth’s orbit around the Sun or in the tilt of the Earth on its axis or in volcanic activity or other natural influences, the global temperature would be impacted, either rising or falling. CO2 would either be released into the atmosphere in the case of warming or sequestered in natural sinks in the case of cooling. As atmospheric levels of CO2 increased, temperature would rise further, continuing the warming trend from the initiating natural force. As atmospheric levels of CO2 decreased, temperature would fall further, continuing the cooling trend from the initiating natural force.
The difference in modern times is that mankind, rather than natural forces, is driving up the levels of CO2 in Earth’s atmosphere. The fact that we have seen a concurrent rise in global temperatures should not be surprising. However, as illustrated in the graph above, now that mankind has pushed atmospheric CO2 to levels not seen in more than 400,000 years and in such a short period of time, we, as a species, are in uncharted territory as to how Earth will react.