A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity.
While there is no global standard for what size a body of ice must be to be considered a glacier, USGS scientists in Glacier National Park use the commonly accepted guideline of 0.1 square kilometers (about 25 acres) as the minimum size of a glacier.
In addition to qualitative methods like Repeat Photography, USGS scientists collect quantitative measurements of glacier area and mass balance to track how some glaciers are retreating (
“Benchmark Glacier” refers to four North American glaciers that have been selected for long-term glacier monitoring that investigates climate, glacier geometry, glaci
Glaciers act as reservoirs of water that persist through summer. Continual melt from glaciers contributes water to the ecosystem throughout dry months, creating perennial stream habitat and a water source for plants and animals.
If all of the glacier ice on Earth were to melt, sea level would rise ~ 80 m (~ 265 ft), flooding every coastal city on the planet.If all of Earth’s temperate glaciers melted, sea level would rise ~ 0.3 – 0.6 m (~ 1 -
The Last Glacial Maximum (LGM) occurred about 20,000 years ago, during the last phase of the Pleistocene epoch. At that time, global sea level was more than 400 feet lower than it is today, and glaciers covered approximately:
Glaciers exist on every continent except Australia. Approximate distribution is:
A temperate glacier (as opposed to a polar glacier) is a glacier that’s essentially at the melting point, so liquid water coexists with glacier ice. A small change in temperature can have a major impact on temperate glacier melting, area, and volume.
About 2.1% of all of Earth's water is frozen in glaciers.