Variability of the Earth’s climate - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 38

Figure 2.8. Inclusion of LGM point in relationship between CO 2 concentration and T G .
that ''deep ocean temperature change is a useful approximation of global mean
surface temperature change on millennial time scales.'' Third, Hansen and Sato's
claim that the amplification at high latitudes is balanced by smaller temperature
rises over the ocean may not be correct quantitatively, even though these do
operate in opposite directions. Hence, Hansen and Sato made assertions that are
not backed up by data.
Hansen and Sato (2011) added the caveat that ''deep ocean temperature
change becomes less representative of global surface temperature change as the
ocean temperature approaches the freezing point of water, because the deep ocean
temperature is limited by the freezing point while the global mean surface can
continue to cool.'' They then asserted without proof that over the past half
million years or so, as deep-ocean temperatures approached the freezing point,
''the amplitude of recent glacial-interglacial deep ocean temperature change is