Accretion. The Earth and all bodies with sufficent mass gain more, and as they gain, their mass increases, causing more accretion. The figure I’ve seen most is 0.1%/year(dust, meteors, and water), but even at a magnitude less(.01%), it adds up.
At a 0.1% per year increase, you could have a 2,100% gain in only 10,000 years, if I did my math right. Accretion would explain an increase in gravity.