Historical Simulations of an Astronomically-Based Climate Model vs. Those of the Global Circulation Models Promoted by the IPCC

Scafetta (2012) tested the performance of his astronomically-based empirical harmonic climate model (Scafetta, 2010, 2011) - which assumes that the climate system is resonating with, or is synchronized to, a set of natural frequencies (quasi 20- and 60-year cycles) of the solar system - against the performance of all of the climatic general circulation models (GCMs) that were evaluated (i.e., promoted) by the IPCC (2007).

In doing so, Scafetta reports that all of the GCMs that were studied by the IPCC (2007) "seriously fail to properly reconstruct even the large multi-decadal oscillations found in the global surface temperature record," but he demonstrates that his astronomical empirical harmonic model is "capable of reconstructing and, more importantly, forecasting the decadal and multi-decadal oscillations found in the global surface temperature with a sufficiently good accuracy."

The researcher - who hails from the Active Cavity Radiometer Solar Irradiance Monitor Laboratory and Duke University at Durham, North Carolina (USA) - states that by not properly reconstructing the 20-year and 60-year natural cycles found in Earth's surface temperature record, "the IPCC GCMs have seriously overestimated the magnitude of the anthropogenic contribution to the recent global warming." And as a result, with respect to the future, he says that whereas the IPCC models project a warming of 1.0-3.6°C by the end of the current century, his model suggests a global warming in the range of 0.3-1.2°C by 2100, which is considerably more in line with the real-world and observation-based assessments of Earth's climate sensitivity that were empirically derived several years ago by Idso (1998) and more recently by Lindzen and Choi (2009, 2011).

Additional References
Idso, S.B. 1998. CO₂-induced global warming: a skeptic's view of potential climate change. Climate Research 10: 69-82.

Lindzen, R.S. and Choi, Y.-S. 2009. On the determination of climate feedbacks from ERBE data. Geophysical Research Letters 36: 10.1029/2009GL039628.

Lindzen, R.S. and Choi, Y.-S. 2011. On the observational determination of climate sensitivity and its implications. Asia-Pacific Journal of Atmospheric Sciences 47: 377-390.

Scafetta, N. 2010. Empirical evidence for a celestial origin of the climate oscillations and its implications. Journal of Atmospheric and Solar-Terrestrial Physics 72: 951-970.

Scafetta, N. 2011. A shared frequency set between the historical mid-latitude aurora records and the global surface temperature. Journal of Atmospheric and Solar-Terrestrial Physics 74: 145-163.