We haven’t done hockey sticks here in a while, but there’s a paper in the new Journal of Climate worth noting in this regard:

High variability in reconstructions does not hamper the detection of greenhouse gas–induced climate change, since a substantial fraction of the variance in these reconstructions from the beginning of the analysis in the late thirteenth century to the end of the records can be attributed to external forcing. Results from a detection and attribution analysis show that greenhouse warming is detectable in all analyzed high-variance reconstructions (with the possible exception of one ending in 1925), and that about a third of the warming in the first half of the twentieth century can be attributed to anthropogenic greenhouse gas emissions. The estimated magnitude of the anthropogenic signal is consistent with most of the warming in the second half of the twentieth century being anthropogenic.

Detection of Human Influence on a New, Validated 1500-Year Temperature Reconstruction, Hegerl et al., Journal of Climate. Vol. 20, No. 4, February 2007, DOI: 10.1175/JCLI4011.1