If you have a graph of measured CO2 levels, how does that qualify as a "record of human-caused climate change"?

Historic Marker to Memorialize the Keeling Curve ::

The site where Scripps Institution of Oceanography at UC San Diego geochemist Charles David Keeling launched what has become the world's most famous record of human-caused climate change will be memorialized by the American Physical Society (APS) in a June 17 ceremony.