Basically, mathematicians have devised a means by which they can
take oscillatory data and, in essence, subtract out known cycles in order to observe how the data is changing independent of these known annual, solar, and paleoclimatic cycles.
The shaded area in Fig. 2B shows the 10 — 90 % confidence intervals for the global temperature signal associated with higher order,
oscillatory discriminants
taken from the same ensemble of climate simulations as above.