evidence: As for what significance, if any, this finding might have to modern climate change, and Antarctica’s melting glaciers, Wellner notes that it is difficult to make direct parallels. Today’s atmospheric carbon dioxide levels are well below mid-Cretaceous levels, but climbing. And continental landmasses have moved over millions of years — pushed and pulled by Earth’s shifting tectonic plates — leading, in part, to ocean and atmospheric circulation patterns that differ from those of the deep past.