Glaciers are slowly moving masses of ice that form when snow remains in an area year-round and compresses into ice. There are two main types of glaciers: mountain glaciers and continental ice sheets. Melting glaciers contribute to rising sea levels through thermal expansion of oceans and adding water from melted ice, threatening coastal habitats and endangering wildlife like polar bears and seals. Solutions include reducing emissions that cause global warming to help slow the melting of glaciers.