"It is reasonable to assume that, even if we do not understand the exact mechanism of solar flux upon the red spot"
Where is there any indication that the change in the red spot of Jupiter is anything to do with the Sun? It might indicate Jovian climate change but please post a ref where it states it has anything to do the Sun.

"1. We know that solar flux has an effect upon climate."
It's not unreasonable to suggest that there are other variables affecting the climate as well as C02, but some of the data hte Solar theory is based on is suspect - check out this paper in pdf format.

"2. We know that climactic changes are occurring on ( at least) Earth, Mars, and Jupiter."
So? The climates on every planet and all of the moons with atmospheres are in constant climatic change - always have been and always will be. This is not an argument in favour of the solar hypothesis driving the current increase in global mean temperature of the Earth.

"3. The common factor to the planets is solar flux. Others MAY exist, but solar-system wide changes in universal constants and such have not been proven."
Others do exist - how about the position of the entire solar system as it rotates around the galactic centre? We pass through dust clouds, supernovae debris etc. None proven, but all possible influences on the climates of the planets. Are the atmospheres of all the planets and their moons warming? Refs to articles/papers on this subject would be nice.

"4. To postulate that the solar flux is NOT responsible for climactic change on multiple planets at the same time which do not share an industrial civilisation nor population is NOT a reasonable assumption."
Neither is saying it isn't (especially using a non-existent "all the planets are warming so it ain't our fault" theory). I don't know whether it is or not - but current scientific analysis of the available data indicates the current rise in global temperatures is due to the increase in anthropgenic C02.

"Just as the increase of atmospheric CO2 on Earth( for whatever reason) and the increase in average temperature could just be coincidence."
Might be, but the guys who job it is to know seem to have a different opinion. For more info on climate change denial, including rebuttals of the main points of the programme and some information on some of the contributors, have a look here.

Still, either way the results are the same. We need to stop pumping C02 into the atmosphere real quick, or the kids will be cleaning up the mess.