From a New York Times story by Raymond Zhong headlined “Something Was Messing With Earth’s Axis. The Answer Has to Do With Us.”:

Around the turn of the millennium, Earth’s spin started going off-kilter, and nobody could quite say why.

For decades, scientists had been watching the average position of our planet’s rotational axis, the imaginary rod around which it turns, gently wander south, away from the geographic North Pole and toward Canada. Suddenly, though, it made a sharp turn and started heading east.