Only during interglacials, like the one we are in now, does some of the sea ice melt during summer, when the top of the planet is oriented a bit more towards the Sun and receives large amounts of sunlight for several summer months.
Not exact matches
Until now it had been assumed that thermophilic reptiles survived the Ice Ages
only on the southern peninsulas of Europe and spread northward once the temperatures rose again
during the Holocene and the
interglacial periods.
For example, Hansen & Sato argued that since GAT
during the Eemian (last
interglacial before the present) was
only slightly higher (less than 1 degree C) and sea levels 4 - 6 meters higher, a 2 degree rise in GAT in the near future will result flooding very quickly.
* It would take
only a small further reduction in climate forcing (less long - lived GHGs or whatever) to yield more ice
during the glacial phase of glacial -
interglacial oscillations.
Quite so but
only because,
during the current
interglacial low solar activity generally occurs around the same time as low rates of energy release from the oceans so that
during the LIA the quiet sun was mitigating the effect of the cooler ocean surfaces.