There is little doubt the air’s CO2 concentration has risen significantly since the inception of the Industrial Revolution; and there are few who do not attribute the CO2 increase to the increase in humanity’s use of fossil fuels.
A weak short-term correlation between CO2 and temperature proves nothing about causation. Proponents of the notion that increases in the air’s CO2 content lead to global warming point to the past century’s weak correlation between atmospheric CO2 concentration and global air temperature as proof of their contention. However, they typically gloss over the fact that correlation does not imply causation, and that a hundred years is not enough time to establish the validity of such a relationship when it comes to earth’s temperature history.
The observation that two things have risen together for a period of time says nothing about one trend being the cause of the other. To establish a causal relationship it must be demonstrated that the presumed causeprecedes the presumed effect. Furthermore, this relationship should be demonstrable over several cycles of increases and decreases in both parameters. And even when these criteria are met, as in the case of solar/climate relationships, many people are unwilling to acknowledge that variations in the presumed cause truly produced the observed analogous variations in the presumed effect.
In thus considering the seven greatest temperature transitions of the past half-million years – three glacial terminations and four glacial inceptions – we note that increases and decreases in atmospheric CO2 concentration not only did not precede the changes in air temperature, they followed them, and by hundreds to thousands of years!