AGW only makes the claim that CO2 is the primary driver of the warming trend seen over the last 100 years.

Well, if it's the "primary" driver then it should have overwhelmed the SO2 during that period.

All you've done is proved that NGHers (Naturogenic Global Heaters) that the natural production of sulfur dioxides is far more powerful regulator of temperature than tail pile CO2.

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If you look at the temperature record for the 1990s, you'll notice a sharp drop in '92, '93, and '94. This is the effect of massive amounts of SO2 ejected into the stratosphere by Mount Pinatubo's eruption. That doesn't mean CO2 took a holiday and stopped influencing global temperatures; it only means that the CO2 forcing was temporarily overwhelmed by another, opposite forcing.

If you take a closer look at the graph, you'll see that there are dozens of similar sharp drops to the one in the early 1990's, they seem to occur with a frequency of 5 to 10 years.  The sharp drop in the early 1990's is completely unremarkable in this sense therefore I see no sound basis for suggesting that the cause of this drop was due to the Mount Pinayubo eruption.

I will change my mind and say I agree that the sharp drops could be due to volcanic eruptions but the obvious reason is ash build-up in the atmosphere blocking out the suns rays, it is a weel known fact that atmospheric ash after a major eruption effects global temperatures.  Therefore it's unlikely that SO2 had anything to do with these drops.

Early 20th century temperature rise was due to the increase in solar activity and the increase in ghg.  The mid century lull was due to increasing particulate emissions, especially sulfates, at a rate much faster than GHG.  Post ~1980 warming is due to much faster increasing levels of GHG, and flattening and then declining SO2 emissions.

Early 20th century temperature rise was due to the increase in solar activity and the increase in ghg.  The mid century lull was due to increasing particulate emissions, especially sulfates, at a rate much faster than GHG.  Post ~1980 warming is due to much faster increasing levels of GHG, and flattening and then declining SO2 emissions.

It's very unlikely that the mid century cooling effect was due to sulphates.  The reason for this is sulphates largely originate from sulphur which forms a part of all fossil fuels especially coal has a large percentage of sulphur.  So since the beginning of the industrial revolution sulphates and greenhouse gas emmissions would largely have increased together, ie in relative terms sulphate emmissions would have been higher than greenhouse gases (in relative terms) much earlier on in the industrial revolution before there were any environmental regulations governing sulphur pollution.  However, since the industrial revolution wasn't accompanied by cooling the suggestion that cooling this century was caused by sulphates can more or less be dismissed.

Since it can be shown that mid century cooling cannot have been caused by sulphates, it strongly suggests that the dominant mechanism governing global temperature is natural.

In the mid 20th century, the rate of increase of sulfate emissions outpaced that of CO2.  This, combined with a relatively high amount of natural particulates in the atmosphere caused the slight cooling period.  Sulfate emissions (which do not perisist in the atmosphere) have since flattened and then dropped, while CO2 emissions (which are cumulative) have only accelerated.

You know the problem with this post? That chart, courtesy of Global Warming Art, that shows the correlation between the reality and the model. Why is it a problem? Because the modeling was done in hindsight!
It's easy to fit a model to existing data. And you don't have to be consciously trying to cheat either. It's a natural human tendency.
For example, around 1900 the data and the model fit almost perfectly. Yet nobody was doing climate modeling of this kind in 1900.
Therefore, the chart is nothing more than an exercise in PR. It's not science.

Carboncat is making a good point.  The climate models all base future projections on past data, it would be silly and irresponsible not to.  However, having your model predict that past data you based it on is only really a check of how well you did your math when coming up with the model, not a check of how good future predictions will be.  

The problem with the response to this argument is it paralels a sceptic claim about the problems with the global warming theory.  Sceptics would say there's no real evidence any of this warming was not due to natural causes.  The response to the argument about mid century cooling takes the form of: there's no real evidence any of this cooling was not due to natural causes.  You can't have your cake and eat it too.