The astronomical theory and data compared - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 317

Imbrie model with SPECMAP ocean data (as shown in Figure 10.4 ) shows the
agreement to be moderate at best—such a simple ice model is highly approximate.
On the other hand, Roe (2006) showed that if the slope of the SPECMAP curve
(the rate of change in ice sheet volume, dV

=

dt) is compared with the solar
intensity curve over the past 800,000 years, the agreement is quite remarkable.
Even though the SPECMAP curve was tuned to the solar intensity curve, this
agreement provides a strong indication that the astronomical theory of ice ages is
inherently correct. Nevertheless, it is not clear how ice ages terminate or why they
should do so in a sudden manner.