Global warming 'unparalleled' in 2,000 years

We knew or know its warming but if you dont say its caused by man, you are fired and your studies are not funded by the university.

The study is interesting in that they looked at rates instead of the usual global mean temperature anomaly, and they used several proxies from different locations rather than a single type of proxy. I would be interested in how they weighted each type and how they resolved conflicting rate indications between proxies. I would also be interested to hear the theories on the spike in rates from ~1900 to ~1930 (beyond their assigned "natural" limits) and the rapid drop from 1930 to ~ 1975. Most of the 1.5B population of the Earth in 1900 was NOT industrialized...so how did humans drive the spike beyond natural limits. And why, if humans caused the spike, did it drop so much from 1930 to 1975? All volcanic activity variations? Attached is NOAA data based in GISP 2 and ice core data (Greenland only, not global) looking much further back.