The authors correlated reconstructed CO2 levels, sunspots, and temperatures from ice-core data from Vostok Antarctica and find
"We find that the variations of SSN [sunspot number] and T [temperature] have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that of T by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO2 and T are neither strong nor stable."
Thus, the well known ~1000 year climate cycle responsible for the Holocene Climate Optimum 6000 to 4000 years ago, the Egyptian warm period ~4000 years ago, the Minoan warm period ~3000 years ago, the Roman warm period ~2000 years ago, the Medieval warm period ~1000 years ago, and the current warm period at present all roughly fall in this same 1000 year sequence of increased solar activity associated with warm periods.
|a) sunspots, b) temperature, c) CO2, d-i show the amplitudes of the strongest cycle lengths (period in years) shown in the data for sunspots, temperature, and CO2
|Wavelet analysis in graph a shows the most prominent solar periods in red and graph b for temperature. The most stable period for both is at ~1024 years, shown by the horizontal region in red/yellow/light blue.
The authors find temperature changes lag solar activity changes by ~40 years, which is likely due to the huge heat capacity and inertia of the oceans. Warming proponents attempt to dismiss the Sun's role in climate change by claiming 20th century solar activity peaked at around 1960 and somewhat declined from 1960 levels to the end of the 20th century (and have continued to decline in the 21st century right along with the 18+ year "pause" of global warming).
Firstly, the assumption that solar activity peaked in 1960 and declined since is false, since it is necessary to determine the accumulated solar energy over multiple solar cycles, which is the accumulated departure from the average number of sunspots over the entire period, which I call the "sunspot integral." The sunspot integral is plotted in blue and shows remarkable correction with global temperatures plotted in red below. Correlating sunspot and temperature data with and without CO2, we find the sunspot integral explains 95% of temperature change over the past 400 years, and that CO2 had no significant influence (also here).
Secondly, this paper finds strong evidence of a 30-40 year lag between solar activity and temperature response. So what happened ~40 years after the 1960 peak in sunspot activity? Why that just so happens to be when satellite measurements of global temperature peaked with the 1998 El Nino [which is also driven by solar activity], followed by the "pause" and cooling since.
We have thus shown
- Strong correlation between solar activity and climate over the past 11,000 years of the Holocene
- Strong lack of correlation between CO2 and climate over the past 11,000 years of the Holocene
- Solar activity explains all 6 well-known warming periods that have occurred during the Holocene, including the current warm period
- The 20th century peak in sunspot activity is associated with a 40 year lag in the peak global temperature
What more proof do you need that it's the Sun!
But wait, there's more. Please see the two previous posts demonstrating that the alternate 33C greenhouse effect is due to atmospheric mass/gravity/pressure, not CO2 or water vapor, physical proof & observations that water vapor is a strong negative-feedback cooling agent, and physical proof that CO2 cannot cause any significant global warming. All of the above also strongly suggests the increase in CO2 levels is primarily due to ocean outgassing from warming oceans from the Sun, not from CO2 radiative forcing warming the oceans, and not primarily from man-made CO2 emissions.