Growing plants outdoors takes a lot of water, and growing them indoors takes a lot of energy for the lighting.
Since lab grown meat won't need all that light, energy costs might be lower, but maybe the energy to keep the growth happening at the right temperature will be quite high. You could offset some of that though with where its grown. Ultimately if we can do it close to room temperature that would be ideal, but I have no idea what the requirements are.
Overall though it might be exceptionally environmentally and climate friendly in it's own rights, not just compared to raising the animals to kill them.