Glacier ice, like limestone for example , is a type of rock. Glacier ice is actually a mono-mineralic rock a rock made of only one mineral, like limestone which is composed of the mineral calcite.
The mineral ice is the crystalline form of water H 2 O. Most glacier ice forms through the metamorphism of tens of thousands of individual Why is glacier ice blue? Glacier ice is blue because the red long wavelengths part of white light is absorbed by ice and the blue short wavelengths light is transmitted and scattered.
The longer the path light travels in ice, the more blue it appears. Where are glaciers found in continental North America? Glaciers exist in both the United States and Canada. Most U. Where on Earth are temperate glaciers located? A small change in temperature can have a major impact on temperate glacier melting, area, and volume. How does present glacier extent and sea level compare to the extent of glaciers and global sea level during the Last Glacial Maximum LGM?
Filter Total Items: 8. Witter, Robert C. View Citation. Witter, R. Williams, Richard S. Year Published: The United States National Climate Assessment - Alaska Technical Regional Report The Alaskan landscape is changing, both in terms of effects of human activities as a consequence of increased population, social and economic development and their effects on the local and broad landscape; and those effects that accompany naturally occurring hazards such as volcanic eruptions, earthquakes, and tsunamis.
Markon, Carl J. Stuart; Markon, Carl J. Stuart, III. Year Published: Satellite image atlas of glaciers of the world U. Date published: May 10, Date published: December 9, In this Landsat EarthView, one glacier in Chile bucks the global trend:.
Date published: September 28, Date published: March 18, Date published: January 20, Despite their comparatively small area, glaciers contribute significantly to global sea level rise 1.
But field campaigns to the ice are difficult, and in situ measurements of ice extent are time consuming, expensive, and cannot possibly be applied to all the glaciers in the world. Instead, we can use remote sensing of glaciers to estimate their size and volume. The Landsat programme, for example, has provided four decades of Earth imaging, meaning that we can analyse glaciers from to the present day.
The succession of Landsat satellites means that we can do repeated inventories, measuring glacier change at decadal scale resolution or better. The table below lists some of the characteristics of each of the successive Landsat satellites, with their Launch and End of Service dates. From onwards, the glacier has been fast receding. Landsat images of the glacier from to show its rapid recession. It is one of the most rapidly changing glaciers in the world.
The figure below, from NASA, shows the glacier extent in You can see the glacier terminus, right out in the mouth of the fjord. Medial Moraines form where two trunks of the glacier merge. Columbia Glacier in The glacier remained near the mouth of Columbia Bay until , when it began to rapidly recede. This is continuing today. Since the s, it has receded more than 20 km to the north, retreating by up to 1 km per year.
The GIF below is a series of Landsat images from to You can see the terminus receding north up the bay. The bright white blocks in the sea are icebergs that have calved from the terminus.
Glacier inventories are a specific technique for mapping glacier extent, volume and characteristics. It ensures that inventories carried out in different places by different people are comparable. This means that we can conduct large meta-analyses of the entire dataset.
The inventories should include glacier attributes, such as area, length, slope, aspect, terminal environment calving into the sea or lake, or terminating on dry land , elevation, and glacier classification. Landsat images can also be used to map transient snow lines, the snowline at the end of the summer, which can be a proxy for the equilibrium line altitude These data provide baseline information for an assessment of glacier changes.
Landsat 8 image of the Battle Glacier Complex, Alaska. Walking through the various labs filled with cylinders of standardized gas mixtures, absolute manometers, and gas chromatographs, Tans offers up a short history of atmospheric monitoring.
In the late s a researcher named Charles Keeling began measuring CO2 in the atmosphere above Hawaii's 13,foot 4,meter Mauna Loa. The first thing that caught Keeling's eye was how CO2 level rose and fell seasonally. That made sense since, during spring and summer, plants take in CO2 during photosynthesis and produce oxygen in the atmosphere. In the fall and winter, when plants decay, they release greater quantities of CO2 through respiration and decay.
Keeling's vacillating seasonal curve became famous as a visual representation of the Earth "breathing. Something else about the way the Earth was breathing attracted Keeling's attention. He watched as CO2 level not only fluctuated seasonally, but also rose year after year. Carbon dioxide level has climbed from about parts per million ppm from Keeling's first readings in to more than ppm today.
A primary source for this rise is indisputable: humans' prodigious burning of carbon-laden fossil fuels for their factories, homes, and cars. Tans shows me a graph depicting levels of three key greenhouse gases—CO2, methane, and nitrous oxide—from the year to the present. The three gases together help keep Earth, which would otherwise be an inhospitably cold orbiting rock, temperate by orchestrating an intricate dance between the radiation of heat from Earth back to space cooling the planet and the absorption of radiation in the atmosphere trapping it near the surface and thus warming the planet.
Tans and most other scientists believe that greenhouse gases are at the root of our changing climate. The three lines on the graph follow almost identical patterns: basically flat until the mids, then all three move upward in a trend that turns even more sharply upward after We know their radiative properties," he says.
Exactly how large that effect might be on the planet's health and respiratory system will continue to be a subject of great scientific and political debate—especially if the lines on the graph continue their upward trajectory. Eugene Brower, an Inupiat Eskimo and president of the Barrow Whaling Captains' Association, doesn't need fancy parts-per-million measurements of CO2 concentrations or long-term sea-level gauges to tell him that his world is changing. In his fire chief's truck, Brower takes me to his family's traditional ice cellars, painstakingly dug into the permafrost, and points out how his stores of muktuk—whale skin and blubber recently began spoiling in the fall because melting water drips down to his food stores.
Our next stop is the old Bureau of Indian Affairs school building. The once impenetrable permafrost that kept the foundation solid has bucked and heaved so much that walking through the school is almost like walking down the halls of an amusement park fun house. We head to the eroding beach and gaze out over open water. We continue our tour. Barrow looks like a coastal community under siege.
The ramshackle conglomeration of weather-beaten houses along the seaside gravel road stands protected from fall storm surges by miles-long berms of gravel and mud that block views of migrating gray whales.
Yellow bulldozers and graders patrol the coast like sentries. The Inupiat language has words that describe many kinds of ice. Piqaluyak is salt-free multiyear sea ice. Ivuniq is a pressure ridge. Sarri is the word for pack ice, tuvaqtaq is bottom-fast ice, and shore-fast ice is tuvaq.
For Brower, these words are the currency of hunters who must know and follow ice patterns to track bearded seals, walruses, and bowhead whales. There are no words, though, to describe how much, and how fast, the ice is changing. Researchers long ago predicted that the most visible impacts from a globally warmer world would occur first at high latitudes: rising air and sea temperatures, earlier snowmelt, later ice freeze-up, reductions in sea ice, thawing permafrost, more erosion, increases in storm intensity.
Now all those impacts have been documented in Alaska. Before leaving the Arctic, I drive to Point Barrow alone. There, at the tip of Alaska, roughshod hunting shacks dot the spit of land that marks the dividing line between the Chukchi and Beaufort Seas. Next to one shack someone has planted three eight-foot 2.
The baleen, curiously, looks like palm fronds. So there, on the North Slope of Alaska, stand three makeshift palm trees. These statements circulated online between late October and early November and coincided with the start of COP26, the United Nations climate change summit.
Reuters has previously addressed instances of misinformation shared in tandem with the Glasgow event, which vary in topic from the talks themselves, to general claims about climate change here , here , here , here and here. That is because there was no satellite imagery at that time, he added.
Marzeion directed Reuters to the Randolph Glacier inventory www. It now lists around , glaciers.
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