Last Tuesday I wrote up Misleading yourself with graphs, prompted by plots on the main page at co2sceptics. As I mentioned then, it could have been an honest mistake, so I sent a note to them on their site (message form).
They've neither responded nor changed their site. So I'm afraid they're simply an unreliable source. Maybe the mistake is honest, maybe not. But a reliable site would respond on being shown that they'd made a mistake and were misleading themselves and their readers.
This is less of a surprise to me now since I searched on their name and found one of the references to them is an earlier post of mine about a different unreliable source icecap.us. In that case, they were being extremely un-skeptical.
In Does CO2 Correlate with Temperature, to appear shortly, I'll be taking a more quantitative look at the correlation they want readers to believe does not exist.