In the background are slow century scale changes in solar output. (newclimatemodel.com)
Have you considered the possibility of century scale acceleration in OHU? (bishop-hill.net)
Statistical analysis of the carbon and oxygen stable isotope recordsr eveals variations in the periods around 100, 11 and 3 years.A century scale connection between the 13C / 12C record and solar activity is most evident.» (notrickszone.com)