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DomeC Temp+CO2 with smoothing

Notes:

This is a plot of smoothed DomeC data.

Note the shift from 40K year glaciation cycles in the distant past to 100K year cycles more recently. It appears that the system is close to returning back to 40K glaciation periods. The specific glacial epoch periodicity depends on the relative phase relationships among the various forcing influences, all of which arise from variability in the Earth's orbit and axis.

This illustrates the proper use of the term 'forcing', where the effect changes the energy entering the system. Greenhouse gases are frequently and incorrectly referred to as forcing influences. Unlike orbit and axis variability, greenhouse gases have almost no effect on the energy budget.