eli5: Earth’s water doesn’t increase or decrease?

Question

So I have always read/heard that Earth’s water never increases or decreases but didn’t it come from icy comets in the first place? Wouldn’t even the small ones that hit us all the time and burn up in the atmosphere still release evaporated water?

In: 1

Answer 1

Water is also produced from combustion and respiration

Combustion from fossil fuels is estimated to create 1.2 × 1013 kg per year (https://iopscience.iop.org/article/10.1088/1748-9326/aa8390)

There is about 1.37 × 1021 kg of water in the oceans (https://hypertextbook.com/facts/1998/AvijeetDut.shtml)

So 0.000001% of the mass of the ocean is created yearly.