“No amount of human activity”
I believe you are wrong. Massive minning extractions from the moon over some long period of time could do it. The moon is only 1.2% of the mass of the earth yet its impact is large in many ways. Changing its mass by massive minning extractions could over time change the affect it has on the earth.
What is the mass of all of the buildings, structures, vehicles, digital watches, and road surfaces, man has made on the earth so far?