First, sea level IS NOT being evaporated. The level of the sea is changing, but we do have a water cycle that keeps the water in balance. So the energy that evaporates water provides the water for rain, etc. What DID happen was that the energy levels were insufficient and the precipitation was mainly frozen and did not get back to the oceans. This caused the sea level to drop.
The sun. The reason the sea lost 400 feet of water is because it wasn’t replaced as rain. It fell as snow which never melted and formed enormous ice sheets up to a mile thick. The sun evaporates enormous amounts of the earth’s ocean every day, but the water is able to be recycled.
from the sun of course. due to man’s pollution to the atmosphere aka the ozone layer, the penetration of the sun is easily transmitted towards the earth. the energy created by the sun is so powerful that it aids the earth in its own distruction, thus, the rising of the sea level has occured.
All energy is a product of the sun. Water can exist in three states, solid, liquid, and gas. These are changing from one to another all the time. During an ice age the gas is changing into a solid (snow, ice) more than it is to a liquid. The sea wasn’t being evaporated at any significant rate that was different from before the ice age or now. But, when it changed into snow and ice and piled up on land it did not flow back to the ocean to replenish what was lost, not until the end of the ice age. Water on the earth isn’t lost or created but the ratio between the three states might change.