A new global analysis of the last 19 million years of seafloor spreading rates found they have been slowing down. Geologists want to know why the seafloor is getting sluggish.

New study led by UMass Amherst suggests that increasing aridity, not temperature change, contributed to the Norse abandonment of Greenland settlements in the 15th century.

Between 26-15 My ago, forests covering west-central North America gave way to open, grassy habitats. Now, oxygen isotope records suggest this shift is owed to drier winters and increased aridity.