How climate models dismiss the role of the Sun in climate

The IPCC attributes 20th century global warming primarily to CO2 on the basis climate models, claiming that the increase in solar activity during the 20th century was insufficient to cause the observed warming. Thus, it is claimed, CO2 is by default the only other possible cause of the warming [they don't know how to model ocean oscillations, so those are automatically & conveniently excluded as a cause].

However, climate models are programmed with solar forcing that is 5-13 times less than found by state-of-the-art solar activity reconstructions. For example, the NASA-GISS climate model uses the following solar forcing assumption:

which shows solar activity increased during the 20th century by only about 0.15 Watts per meter squared [W/m2]. Contemporary solar activity reconstructions, however, show that solar activity increased during the 20th century by 1.5 - 4 W/m2 or 10 - 26 times more than assumed by the NASA-GISS model. If one assumes 30% albedo and divide by four [an incorrect and simplistic assumption as demonstrated by Joe Postma], the GISS model uses up to ~5 times less solar forcing anomaly change in comparison to solar proxy data. 

Reconstructed Total Solar Irradiance [TSI] shown in upper right graph shows an increase of  ~ 4 W/m2 over the 20th century

Solar forcing based on these modern reconstructions is 1 - 2.6 times higher than the alleged forcing from increased greenhouse gases during the 20th century. In addition, climate models do not consider any of the multiple solar amplification mechanisms which have been described in the literature. Thus, the IPCC and others dismiss the role of the Sun in climate by conveniently assuming solar activity changed 5 - 13 times less than the research indicates. 

In addition, since solar forcing was much higher than assumed by the models, this implies that CO2 forcing was significantly less than assumed by the models.