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"Surface temperature reconstructions for periods prior to the industrial era are only one of multiple lines of evidence supporting the conclusion that climatic warming is occurring in response to human activities, and they are not the primary evidence."

So the reconstructions are wrong, but it doesn't matter because there is other evidence? Well, if they are wrong why do folks keep using the models as if they were gospel?

Also, what is the "primary evidence" that human activities are causing global warming?

I know you have been around here long enough to know that most here don't believe that humans are causing global warming. We're probably split as to whether the earth is warming at all. But if you have more than anecdotal evidence or speculation that people cause global warming I would be happy to see it.

So the reconstructions are wrong, but it doesn't matter because there is other evidence? Well, if they are wrong why do folks keep using the models as if they were gospel?

Paleotemperature reconstructions and climate models are not the same thing. I would read the links to better characterize the arguments; the RealClimate side is emphasizing that they acknowledged the uncertainties of their pre-1600 reconstruction. Nonetheless, the hockey stick presented by the IPCC made it seem certain that the 1900s were the warmest period of the past 1,000 years. That's not certain.

What is critical is whether or not the current warming trend is related to human activities (some of the warming probably is); if so, how much is caused by human activities (still working on it); and how much faster the expected rate of change will be compared to natural climate variability ups-and-downs (as the Panel says, that needs more research).

But if you have more than anecdotal evidence or speculation that people cause global warming I would be happy to see it.

The certainty is that the increase in atmospheric CO2 since 1850, 80 ppm higher than the highest natural CO2 concentration observed in the past 640,000 years (ice core data) is due to human activities. Increasing CO2 concentration will change Earth's radiative balance such that, with all other quantities held constant, global temperature would increase. The problem is that all other quantities are not constant, so determining how much warming is clearly human-caused is difficult. Climate feedbacks in response to CO2 radiative forcing can be positive or negative. It appears that the balance sheet will favor the positive side of feedback, augmenting the warming due to CO2, but that is not in any sense definitive.