Kids Climate : What causes sea level to rise?

There are two main causes of sea level rise and both are due to heat. Glaciers and ice sheets are large masses of ice that sit on the land. As our planet warms, this ice melts and flows into the oceans. More water in the oceans makes sea level higher.
Secondly, water expands as it gets warmer. So, warm water takes up more room in our oceans – making sea levels higher.