[ancient_geezer]

It seems that supporters of global warming refuse to admit to the possibility of climate and solar cycles that are hinted at with periods of 1500+ years.

That is probably the understatement of the year.

The following is typical of input data for modeling solar irradiation with regards projection runs (in the particular NASA's http://data.giss.nasa.gov/modelE/ ).

Note the lack of long term variation in solar component after 2000. No attempt is made to take even the well known 80-year Gleissberg or 200-year Suess solar cycles into account in projections the longterm solar irradiation is assumed constant with only a fixed period/magnitude sunspot cycle.

Data @ NASA GISS Earth's Energy Imbalance Simulations

Data @ NASA GISS Forcings in GISS Climate Model

Data @ NASA GISS Forcings in GISS Climate Model Solar Iradiance:

 

This figure summarizes data obtained from Judith Lean and used in GISS GCM runs.

postscript (154 kb), README, tabular data (420 kb)

Instantaneous forcing was computed continuously from 1850 to 2000 using Model E with 16 layers.

tabular data (2 kb), postscript (35 kb) postscript, 1850 to 2000 (35 kb)

[ancient_geezer]

Of course one might also wonder how such a low long term solar variation comes about.

When one makes aprior assumptions about the contribution of solar variation to change in global temperature since the Maunder minimum, selecting a dataset to fit a CO2 driven hypothesis becomes a snap.

Data archives are so illuminating when one digs around in them abit:

Index of -pub-data-paleo-climate_forcing-solar_variability

http://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/bard_irradiance.txt

2. Data from Figure 3. Reconstructed Solar Irradiance Scaled against Maunder Minimum Total Solar Irradiance reductions of

• 0.25% (Lean et al. 1995),
• 0.40% (Zhang et al. 1994,
• Solanki and Fligge, 1998)
• 0.55% (Cliver et al. 1998), and
• 0.65% (Reid 1997)