For several years, the suggestion that there is positive feedback between atmospheric temperature (T) and carbon-dioxide concentration (CO2) has dominated the scientific literature, and has become a fundamental assumption of climate science. Alternatively, the relationship between T and CO2 might be one of equilibrium. We can test models of each type by comparison with the Vostok record, first published by Petit, et al. (1999).
T and CO2 appear to have been in equilibrium until about 3,000 BCE.
Over the 5,000 years since then, CO2 has risen increasingly above its natural equilibrium. By 1,800 CE, CO2 had risen to a level comparable to the highest in the Vostok record.
During this time, T declined at a rate of 0.1 °C per thousand years,
indicating again that CO2 has no apparent effect on T. The trends of this 5,000-year interval of excess
CO2 are consistent with the equilibrium model, in which T is independent of CO2.
The last 5,000 years are trivial compared to the 420,000 years of the Vostok record; of even less significance are the last 1,200 years. However, climate science has put great emphasis on the features of this interval, even though they fit within the noise-envelope. The “medieval warm period” spanned 800 CE to 1,200 CE; Vostok shows it wasn’t really warm, but wasn’t really cold either. The “little ice age” followed (although average T was barely lower), and ended after the low of -1.84 °C around 1,770 CE. By the early 1800s, T was higher than it is at present, and it has fluctuated within levels typical of the last 11,000 years since then. It is remarkable that climate hysteria should be based on noise-level changes in T over the last 200 years, which is an eye-blink in the Vostok record. It seems to be the superstition of our time.
In summary, the Vostok record indicates that CO2 is in lagged equilibrium with T and that, for the range of T in Vostok, the dependency of CO2 on T is essentially linear. Unnaturally high CO2 for the last 5,000 years has had no apparent effect on T. This empirical evidence supports a conclusion that there cannot be any significant feedback between CO2 and T. Such feedback would cause predicted T and CO2 to show fundamental disagreement with the lag, spectrum and amplitudes evident in the Vostok record.
