Sea-level rise refers to the increase in the average level of the world's oceans. This phenomenon is primarily caused by two factors: the melting of ice sheets and glaciers, and the thermal expansion of seawater as it warms. As global temperatures rise due to climate change, these processes accelerate, leading to higher sea levels. The impacts of sea-level rise can be significant, affecting coastal communities and ecosystems. Areas such as Florida and Bangladesh are particularly vulnerable, facing increased flooding, erosion, and loss of habitat. Addressing this issue requires global cooperation and sustainable practices to mitigate climate change effects.