Why are glaciers blue?

Glaciers store almost 70% of the fresh water in the world and cover 10% of land area on Earth. If all of earth’s glaciers melted, the ocean level would increase 230 feet worldwide. 97% of the glaciers in the United States are in Alaska. Glaciers are beautiful, fragile environments, but do you know why glaciers are blue?

Glacial ice is formed from compacted snow when the amount of melt in an area is less than the amount of snowfall. Compaction over time reduces the space between molecules of water and the ice crystals reform larger and larger as air bubbles are squeezed out. Glacial ice crystals can be as large as baseballs.

The color of a glacier depends on how it interacts with light. Glacial ice with a lot of air bubbles appears white. When all or nearly all of the air bubbles are squeezed out of glacial ice, the ice absorbs a small amount of red light which makes it appear blue.

Icebergs, which are pieces of glaciers that have broken off and are floating in the ocean, can sometimes be green. The green color is caused by the presence of iron oxide or rust in the iceberg. Iron is found in Antarctica’s rock dust, so green icebergs carry dust from Antarctica.

Smoke from the Australian brushfires in 2020 turned some of New Zealand’s glaciers brown and yellow. Scientists fear this will cause melting to accelerate.

Featured image Photo by Vince Gx on Unsplash

Glacial ice Photo by Simon Berger from Pexels