Temperature, among other factors, drives atmospheric CO2 much more than CO2 drives temperature. The rate of change dCO2/dt varies ~contemporaneously with temperature, which reflects the fact that the water cycle and the CO2 cycle are both driven primarily by changes in global temperatures (Veizer et al).

To my knowledge, I initiated in January 2008 the hypothesis that dCO2/dt varies with temperature (T) and therefore CO2 lags temperature by about 9 months in the modern data record, and so CO2 could not primarily drive temperature. Furthermore, atmospheric CO2 lags temperature at all measured time scales. See more including the referenced figures below here.

In my Figure 1 and 2, global dCO2/dt is closely correlated with global Lower Tropospheric Temperature (LT) and Surface Temperature (ST). The temperature and CO2 datasets are collected completely independently, and yet this close correlation exists.

After publishing this paper, I also demonstrated the same close correlation with different datasets, using Mauna Loa CO2 data and Hadcrut3 ST back to 1958. Later I examined the close correlation of LT measurements taken by satellite and those taken by radiosonde.

Earlier papers by Kuo (1990) and Keeling (1995) discussed the delay of CO2 after temperature, although neither appeared to notice the even closer correlation of dCO2/dt with temperature. This correlation is noted in my Figures 3 and 4.

My hypothesis received a hostile reaction from both sides of the fractious global warming debate. All the “global warming alarmists” and most “climate skeptics” rejected it. First I was just deemed wrong - the dCO2/dt vs T relationship was allegedly a “spurious correlation”.

Later it was agreed that I was correct, but the resulting ~9 month CO2-after-T lag was dismissed as a “feedback effect”. This remains the counter-argument of the global warming alarmists - apparently a faith-based rationalization to be consistent with their axiom “WE KNOW that CO2 drives temperature”.

This subject has generated spirited discussion among scientists. Few now doubt the close correlation dCO2/dt vs T. Some say that humankind is not the primary cause of the current increase in atmospheric CO2 - that it is largely natural. Others rely on the “mass balance argument” to refute this claim.

The natural seasonal amplitude in atmospheric CO2 ranges up to ~16ppm in the far North (at Barrow Alaska) to ~1ppm at the South Pole, whereas the annual increase in atmospheric CO2 is only ~2ppm. This seasonal “CO2 sawtooth” is primarily driven by the Northern Hemisphere landmass, which has a much greater land area than the Southern Hemisphere. CO2 falls during the Northern Hemisphere summer, due primarily to land-based photosynthesis, and rises in the late fall, winter and early spring as biomass decomposes.

Significant temperature-driven CO2 solution and exsolution from the oceans also occurs. See the beautiful animation.

In this enormous CO2 equation, the only signal that is apparent is that dCO2/dt varies approximately contemporaneously with temperature, and CO2 clearly lags temperature.
CO2 also lags temperature by about 800 years in the ice core record, on a longer time scale. I suggest with confidence that the future cannot cause the past.
I suggest that temperature drives CO2 much more than CO2 drives temperature. This does not preclude other drivers of CO2 such as fossil fuel combustion, deforestation, etc.
My January 2008 hypothesis is gaining traction with the recent work of several researchers. Here is Murry Salby’s address to the Sydney Institute in 2011:

See also this January 2013 paper from Norwegian researchers: The Phase Relation between Atmospheric Carbon Dioxide and Global Temperature Global and Planetary Change, Volume 100, January 2013 by Humlum, Stordahl, and Solheim

- Changes in global atmospheric CO2 are lagging 11-12 months behind changes in global sea surface temperature.

- Changes in global atmospheric CO2 are lagging 9.5-10 months behind changes in global air surface temperature.

- Changes in global atmospheric CO2 are lagging about 9 months behind changes in global lower troposphere temperature.

- Changes in ocean temperatures explain a substantial part of the observed changes in atmospheric CO2 since January 1980.

- Changes in atmospheric CO2 are not tracking changes in human emissions.

Observations and Conclusions:

1. Temperature, among other factors, drives atmospheric CO2 much more than CO2 drives temperature. The rate of change dCO2/dt is closely correlated with temperature and thus atmospheric CO2 LAGS temperature by ~9 months in the modern data record

2. CO2 also lags temperature by ~~800 years in the ice core record, on a longer time scale.

3. Atmospheric CO2 lags temperature at all measured time scales.

4. CO2 is the feedstock for carbon-based life on Earth, and Earth’s atmosphere and oceans are clearly CO2-deficient. CO2 abatement and sequestration schemes are nonsense.

5. Based on the evidence, Earth’s climate is insensitive to increased atmospheric CO2 - there is no global warming crisis.

6. Recent global warming was natural and irregularly cyclical - the next climate phase following the ~20 year pause will probably be global cooling, starting by ~2020 or sooner.

7. Adaptation is clearly the best approach to deal with the moderate global warming and cooling experienced in recent centuries.

8. Cool and cold weather kills many more people than warm or hot weather, even in warm climates. There are about 100,000 Excess Winter Deaths every year in the USA and about 10,000 in Canada.

9. Green energy schemes have needlessly driven up energy costs, reduced electrical grid reliability and contributed to increased winter mortality, which especially targets the elderly and the poor.

10. Cheap, abundant, reliable energy is the lifeblood of modern society. When politicians fool with energy systems, real people suffer and die. That is the tragic legacy of false global warming alarmism.