From Live Science:
Climate change is making Earth progressively rounder, new research finds.
The findings are a signal of human-caused climate change, however, and tracking the shape of the Earth can help reveal just how much impact people are having on its ice caps. Our planet is not a perfect sphere. Because of its rotation, it is a bit flatter at the poles and bulges in the middle. But the new study reveals that Earth is getting rounder at an accelerated rate, largely due to shifts caused by the melting polar ice caps.