Final answer:
Climate change-induced warming leads to a slight increase in the length of the day due to the movement of polar ice meltwater towards the equator, changing the Earth's moment of inertia. Rising global sea levels also result from expanded warmer water and an added volume of meltwater, which threatens ecosystems and freshwater sources.
Step-by-step explanation:
When there is a significant heating trend on Earth, such as that caused by climate change, several effects come into play due to the melting of the polar ice caps. The redistribution of mass from the poles to the equator because of melted ice water spreading out around the globe changes Earth's moment of inertia. According to the conservation of angular momentum, a decrease in Earth's moment of inertia must be accompanied by an increase in its rotation rate to keep the total angular momentum constant. However, due to the complex distribution of mass and the vast size of the Earth, this effect would be greatly counterbalanced. In reality, the redistribution leads to a slight increase in the length of the day, as the additional mass at the equator slows the rotation slightly.
Furthermore, global sea levels will rise not only due to the direct addition of meltwater from glaciers but also because warmer water expands, occupying a larger volume. As sea levels rise, coastal ecosystems, human communities, and entire islands can face catastrophic inundation. The interruption of the natural cycle of melting and refreezing at the poles, glaciers, and mountains disrupts the provision of freshwater, leading to an overabundance of saltwater and a scarcity of freshwater sources.