Via Climate Depot. Russian scientists have been predicting global cooling for some years. Now two German scientists add to the chorus, finding multiple temperature cycles.
Climate reveals periodic nature, thus no influence by CO2
Prof. H. Luedecke and C.O. Weiss (Original German version here.)
We reported recently about our spectral analysis work of European temperatures  which shows that during the last centuries all climate changes were caused by periodic (i.e. natural) processes. Non-periodic processes like a warming through the monotonic increase of CO2 in the atmosphere could cause at most 0.1° to 0.2° warming for a doubling of the CO2 content, as it is expected for 2100. Fig. 1 (Fig. 6 of  ) shows the measured temperatures (blue) and the temperatures reconstructed using the 6 strongest frequency components (red) of the Fourier spectrum, indicating that the temperature history is determined by periodic processes only. On sees from Fig. 1 that two cycles of periods 200+ years and ~65 years dominate the climate changes, the 200+ year cycle causing the largest part of the temperature increase since 1870.
Fig. 1: Construction of temperatures using the 6 strongest Fourier components (red), European temperatures from instrumental measurements (blue). It is apparent that only a 200+ year cycle and a ~65 year cycle play a significant role.
The ~65 year cycle is the well-known, much studied, and well understood “Atlantic/Pacific oscillation” (AMO/PDO). It can be traced back for 1400 years. The AMO/PDO has no external forcing it is “intrinsic dynamics”, an “oscillator”. Although the spectral analysis of the historical instrumental temperature measurements  show a strong 200+ year period, it cannot be inferred with certainty from these measurements, since only 240 years of measurement data are available. However, the temperatures obtained from the Spannagel stalagmite show this periodicity as the strongest climate variation by far since about 1100 AD.
That dotted line at the end of the graph must be their predicted future values. Temperatures look set to drop quite sharply. They end:
The analysis of solar activity proves the existence and the strength of the 200+ year periodicity which we found from historical temperature measurements, as well as from the Spannagel stalagmite data. This 200+ year cycle is apparently the one known as “de Vries cycle”.
This solar “de Vries cycle together with the AMO/PDO determine practically completely the global climate of the past (Fig. 1) and the coming time. A significant influence of CO2 on the climate thus has to be excluded. This latter is not surprising in view of the small amount of CO2 in the atmosphere and its weak infrared absorption cross section (also in view of the various proves of N
If they’re right, all these global warming alarmists are going to look pretty stupid.