We do live in an interglacial [1] period, which is a slightly warmer, shorter time in the midst of an ice age.
[1] https://en.wikipedia.org/wiki/Milankovitch_cycles [2] https://www.geocraft.com/WVFossils/ice_ages.html
For instance, when oceans change, such as el nino, la nina, reversals of enduring currents, or even new connections between seas due to tectonic transformations, that is properly a cause of climate change -- regardless of how much that change is, in fine, mediated by the atmosphere. Atmospheric changes are demonstrably not the only, nor the ultimate causes, of climate change.