There's probably not a net gain, as a system, because we're also radiating heat out, burning fossil fuels, etc., but the earth isn't a closed system, is it?
If not for the constant influx of sunlight, we'd have to rely on core heat (tube worms and chemoautotrophy) to fuel metabolism, which most species don't do. It's photosynthesis of algae, plants, and cyanobacteria and subsequent predation that allows most life, including us, to flourish, no? And that requires a constant external input of sunlight?
> An Earth mass (denoted as M_E or M⊕ ( M_{\oplus } ), where 🜨 is the standard astronomical symbol for Earth), is a unit of mass equal to the mass of the planet Earth. The current best estimate for the mass of Earth is M🜨 = 5.9722×10^24 kg, with a relative uncertainty of 10^−4. It is equivalent to an average density of 5515 kg/m3.
Average mass of a human: 50-75kg, depending on whether it's babies or not
Population of Earth: 8.1x10e9
Total mass of humans: ~ 400-600 x 10e9
Proportion of Earth's mass composed of live humans: 500e9 / 5.9e24 = 8.4e-14 = 0.00000000000084 %
According to the video series on "How the pyramids were built" at https://thepump.org/ by The Pharaoh's Pump Society, the later pyramids had a pool of water at the topmost layer of construction such that they could place and set water-tight blocks of carved stone using a crane barge that everybody walked to the side of to lift.
Since temperature = energy, e=mc^2, therefore temperature = mass, the earth gains 160 tons/year due to global warming.
So Earth's mass and gravity is therefore decreasing over time. If you assume global warming is directly proportional to population, we'll need ~2.5 trillion people before we can start increasing gravity.
Technological civilization might at some point meaningfully shift the distribution of mass, but I don't think it has up to this point.
“Humans are responsible for some of the wobble in Earth's spin.
Since 1899, the Earth's axis of spin has shifted about 34 feet (10.5 meters). Now, research quantifies the reasons why and finds that a third is due to melting ice and rising sea levels, particularly in Greenland—placing the blame on the doorstep of anthropogenic climate change.”