Shouldn’t Earth’s internal heat also heat the surface?

The text says that sunlight is the source of virtually all heat and energy on Earth’s surface, but shouldn’t Earth’s internal heat also contribute to surface heating? Technically, the answer is yes. However, Earth’s internal heat leaks outward to the surface very slowly — so slowly that the amount of energy the surface as a whole (counting both day and night sides) is receiving from sunlight at any moment is nearly 4,000 times as great as the amount coming from Earth’s interior. As a result, we can generally ignore the very small contribution of Earth’s internal heat to surface heating.

If you think about this further, you’ll also realize why internal heat is so important underground. Heat and energy from the Sun cannot penetrate more than a short distance into the ground. Therefore, Earth’s internal heat is the only source of energy for subsurface processes. The fact that this heat leaks outward toward the surface very slowly then explains (at least in part) why most internal geological processes have very long time scales.