dumping the comets and moons onto the surface is to help with that. But I've done some napkin math and it looks like we need ~40 billion commets to bring it halfway to earth mass...welp
If you crash the entire asteroid belt into Mars, its mass will increase by half a percent.
a good start!
you can get most of that half of a percent with just the 4 largest asteroids.
maybe we need to sacrifice our own moon.
If we are moving the moon, we might as well just move the earth to a higher orbit further from the sun.
If we had access to this kind of energy, we'd be generating and treating copious amounts of antimatter and using it to power electrical CO2 sequestration devices.