Although most of Earth's early historical record has been destroyed by plate-tectonic recycling of rocks, the blurry outline of its tectonic history comes slowly into focus in geologic records from the last 400 million years. One by one, past configurations of its major geographic features—outlines of continents and oceans, and subaerial and subsea topography—become resolvable in varying degree from surviving geologic evidence.
Earlier in this century this kind of information inspired geoscientists to concoct hypotheses to explain the many observations of past climate changes emerging from studies of sedimentary rocks. Tectonic hypotheses of climate change proliferated, unconstrained by rigorous testing. In the last 2 decades, since pioneering work in the early 1980s by Eric Barron, climate models have been used to put quantitative constraints on these ideas, producing an ongoing scientific revolution in our understanding of long-term climate change.