Is it possible that the earth mass would be reducing due to extraction of fossil fuels?
If so, would it affect to its movement and position in solar system?
There won’t be any considerable loss of mass. The amount of mass irrecoverably lost is negligibly small on its conversion to energy .
It’s just like arguing that constructing more and more buildings will increase the mass of earth. !! No such thing happens. There is only a rearrangement of matter and inter conversion of mass and energy.