Solving the coupled Poisson-Schrödinger equation with the exchange-correlation potential in calculating the electron field emission properties under the framework ED-MD-PIC simulation methodology enables the direct evaluation of the space charge quantum many-body effects and their influences on the field emission properties and thermal runaway behavior of metal nanotip. Such a methodology is numerically realized in our in-house hybrid dynamics simulation code known as FEcMD software package. The simulation results for a three-dimensional (3-D) conical Cu nanotip (H0 = 100 nm, r0 = 1 nm and θ0 = 3°) manifests the importance of including space charge quantum effects in calculating the field emission characteristics, and also predicting the thermal runway behaviors of nano- and micro-protrusions in ED-MD-PIC simulations. Specifically, the inclusion of exchange-correlation effects of space charge can substantially lower the electron transmission barrier height when the applied E-field is large and space charge density at the surface of emitter is high, leading to the even larger emission current and a stronger Joule heating mechanism, compared to that of simulation excluding quantum effects at all. As a result, the minimum applied E-field value for initiating the thermal runaway process of nano-emitter is greatly decreased.