All I can do is cite what appear to be reputable sources.
With respect to solar radiation, take a look at Solar flux and sunspots. This site presents data on solar flux, sunspot numbers and a measure of magnetism called the A Index. Click on year 2000 and scroll down through the plots. Observe the striking correlation between solar flux and sunspot numbers. When sunspot numbers go up, so does solar flux. Then look at some year near the bottom of a sunspot cycle when there are few sunspots, like 1985. The level of solar flux is much lower in 1985 than in 2000.
But there's no doubt about that! The question is whether or not changes in solar flux can appreciably affect climate. That's the reason for the whole search for a climate forcing mechanism related to solar variability. The Bond paper found a linkage because they also looked at radionuclides that are related to solar activity.
The strong relation between sunspot numbers and solar flux would seem to explain the correlation between the Little Ice Age and the Maunder Minimum period that had almost no sunspots. Oh, I forgot. The IPCC has thrown out the Little Ice Age as a local phenomenon despite its appearance in temperature proxies all over the globe. Can't have that sun doing things to global temperatures.
I've been over this with a lot of people. Until very recently, the evidence for the Medieval Warm Period was not as strong as for the Little Ice Age. The recent tree-ring data record of Esper (just published in Nature or Science) strengthens the "strength" of the MWP. Nobody ever really doubted there was one, because the Vikings couldn't have settled in Greenland without one. The Mann tree-ring reconstruction cited by the IPCC didn't eliminate the Little Ice Age (as some skeptics have claimed): it integrated records in which it was quite strong (England and some locations in Europe) with other records where it wasn't as strong or it was timed differently. In fact, Mann has an encyclopedia article on the Little Ice Age online that shows a number of these data sets (it's a PDF document):
Look at the figure on page 5. How anyone can look at this data and say that Mann and the IPCC tried to get rid of the "Little Ice Age" is incomprehensible.
Someone from the Wilson Observatory made the comment that doubling the CO2 concentration would have roughly the same effect as a 0.1% change in solar radiation. That is certainly in the range of what has been observed for solar variability.
And that's quite likely true for the full range of solar variability, including the Maunder Minimum. But the question that needs to be better addressed is what's happening now.
The link to a John Daly site mentioned in post 47 of this thread cited some strong evidence of the global nature of the Little Ice Age. The Little Ice Age seems much more pronounced globally than Mann's temperature curve would lead one to believe. In effect, Mann averaged the Little Ice Age out of the data, when many other sets of data he didn't use seem to indicate it was real and global in extent. I had read a number of the original articles cited by Daly when they came out, so I was floored when I saw the temperature history the IPCC uses (Mann's).
I'm all for letting Mann's temperature curve be thrashed out in peer review. In a sense, Daly is giving the Mann tenperature curve a public peer review, and it doesn't pass his criteria. He's an expert in the field; I'm not. Peer review can be a flawed process, as you no doubt know. If your paper is sent only to people who agree with you, your paper gets accepted with little constructive criticism. It is almost a useless process when that happens. I have no idea what peer review Mann's papers went through.
I've seen statements to the effect that a correlation between the solar indices and modeled solar irradiance with the earth's temperature has a significant confidence level exceeding 99% (Hoyt and Schatten, The role of the Sun in Climate Change, pg 195). That is a very high statistical confidence level for the period since about 1700. The model they cite doesn't include greenhouse gas or aerosols.
That is not to say people have determined in detail the mechanism behind the correlation. They haven't.
Some correlations, like the one you cited above, show a small difference between their solar parameters and the observed temperature during the last part of the 20th century. Perhaps this is the effect of greenhouse gases. Whatever it is, the effect is relatively small. If solar radiation is indeed beginning to decrease, we'll need even that small amount of heating to minimize crop failures. Having the sun go into a prolonged down cycle seems worse to me than a relatively minor temperature increase.