User:MeganERenz/sandbox

Movement
When a glacier is experiencing an input of precipitation that exceeds the output, the glacier is advancing. Conversely, if the output from evaporation, sublimation, melting, and calving exceed the glaciers precipitation input the glacier is receding. This is referred to as an interglacial period. During periods where ice is advancing at an extreme rate, that is typically 100 times faster than what is considered normal, it is referred to as a surging glacier. During times in which the input of precipitation to the glacier is equivalent to the ice lost from calving, evaporation, and melting of the glacier, there is a steady-state condition. Within the glacier, the ice has a downward movement in the accumulation zone and an upwards movement in the ablation zone.

Climate Change and Glaciers
Glaciers are a valuable resource for tracking climate change over long periods of time because they can be hundreds of thousands of years old. To study the patterns over time through glaciers, ice cores are taken, providing continuous information including evidence for climate change, trapped in the ice for scientists to break down and study. Glaciers are studied to give information about the history of climate change due to natural or human causes. Human activity has caused an increase in greenhouse gasses creating a global warming trend, causing these valuable glaciers to melt. Glaciers have an albedo effect and with the melting of glaciers means less albedo. In the Alps the summer of 2003 was compared to the summer of 1988. Between 1998 and 2003 the albedo value is 0.2 lower in 2003. When glaciers begin to melt, they also cause a rise in sea level, "which in turn increases coastal erosion and elevates storm surge as warming air and ocean temperatures create more frequent and intense coastal storms like hurricanes and typhoons ." Thus, human causes to climate change creates a positive feedback loop with the glaciers: The rise in temperature causes more glacier melt, leading to less albedo, higher sea levels and many other climate issues to follow. From 1972 all the way up to 2019 NASA has used a landsat satellite that has been used to record glaciers in Alaska, Greenland and Antarctica. This landsat project has found that since around 2000, glacier retreat has increased substantially.