Yes, Earth's rotation would change if surface water was removed, but the impact would be relatively minor. Earth's rotation is influenced by the distribution of mass on its surface. When water is present, it forms large oceans, which are spread unevenly across the planet due to various factors like landmasses, underwater topography, and gravitational interactions.
If all the surface water on Earth were to be removed, there would be some noticeable effects on the planet's rotation. The most significant change would be a small increase in the Earth's rotation rate, resulting in a slightly shorter day. This is due to the principle of conservation of angular momentum. The removal of water from the oceans would redistribute mass toward the polar regions, where the Earth's rotation is faster due to its smaller radius compared to the equator.
The redistribution of mass would cause a slight shift in the Earth's rotational axis, a phenomenon known as "polar wander." However, this shift would likely be negligible in the short term. Over long geological periods, polar wander has indeed occurred due to various natural processes, such as the movement of tectonic plates and the melting and formation of ice sheets.
It's important to note that while the removal of surface water would have an impact on Earth's rotation, the effect would be much smaller than other natural processes happening on the planet. Factors like changes in the distribution of ice, volcanic activity, and even climate change can have more significant effects on Earth's rotation and its axial tilt over geological time scales.
In summary, if all the surface water on Earth were suddenly removed, there would be a slight increase in the planet's rotation rate and a minor shift in the rotational axis, but these effects would be relatively small compared to other natural processes shaping Earth's rotation over long periods.