Chasing the Light

While most glacial ice is located in Antarctica and Greenland, there are actually glaciers on almost every continental landmass, covering approximately 15 million square kilometers (5.8 million square miles)– that’s 10% of Earth’s land surface. Artist Zaria Forman captures the massive, but fragile beauty of these amazing ice and snow formations in her work, and reminds us how important glaciers are to every living being on Earth, now and in the future.

Zaria Forman video courtesy of Ted Conferences LLC,  CC BY-NC-ND

Seventy-five percent (75%) of the world’s fresh water supply is stored within glaciers;  therefore, it’s impossible to overstate their importance to our survival. And, learning just a few basics about glacier formation and loss helps in understanding the urgent need to protect glaciers from melting away.

There are two primary types of glaciers:

Continental:  These are enormous masses of glacial ice and snow, known as “ice sheets”, that flow away from a central region and are mostly unaffected by underlying topography.  Found only in Greenland and Antarctica.

Alpine or Valley:  Glaciers in mountains that flow down valleys.  When two glaciers meet and merge at the base of mountains, the new glacier is called a piedmont glacier.  If the piedmont glacier flows into the sea, it’s called a tidewater glacier.  A cirque glacier is confined by a valley forming in a “cirque” (semicircular bowl-like basin at the head of a valley).  Valley glaciers (aka alpine glaciers) form in a mountain valley when more snow falls on mountain peaks during a year than melts during the summer, creating a snow pack that builds up, thickens, compresses, turns into ice, grows and moves slowing downhill (Mer de Glace and Exit Glacier are examples of a valley glacier).  An Ice Field (also spelled ‘icefield’) is an extensive area of ice and interconnected valley glaciers that usually form over high altitude basins and atop plateaus.  Ice caps cover mountain tops.

Glacial ice is formed by the accumulation and compression of snow and ice over a period of years, often 100 years or more.  It’s not quite as dense as ice formed by freezing water because of tiny air bubbles trapped inside, and this unique composition allows light reflecting as white to be absorbed while blue light is transmitted and scattered, resulting in the distinctive blue color of a glacier.

Formation and survival of a glacier are affected by environmental and geological factors such as the slope of the land, amount of snowfall, temperature and winds.  The surface area of a healthy glacier is covered more than 60% by snow at the end of a melting season and produces good flow.  This requires a delicate balance of variable circumstances, and that’s been continually disrupted in recent history.

Since the early 20^th century, glacier retreat and mass loss have accelerated and become more prevalent.  In fact, several glaciers, ice caps and ice shelves have completely disappeared, and approximately 400 billion tons of glacial ice were lost each year since 1994.  Many other glaciers are shrinking so rapidly they’ll likely vanish in a few more decades. Just one example is Muir Glacier in Alaska.  From 1941 to 2004, it receded about seven miles and lost more than 2,625 feet in depth.

Information/Resources:
Wikipedia (Glacier, Glacier mass balance)
“All About Glaciers“, National Snow and Ice Data Center
Glaciers (terminology, notes and comments), Eastern Illinois University
Some of the Oldest Ice in the Arctic is Now Breaking Apart by Christopher Joyce, NPR Science (August 23, 2018)
“NASA Mission Takes Stock of Earth’s Melting Land Ice” (February 8, 2012) Jet Propulsion Laboratory
NASA Global Climate Change (Glaciers) – Interactive Global Ice Viewer
Common Questions and Myths About Glaciers, US National Park Service
“Steps to Prevent Glaciers from Melting” (February 19, 2016) The New Ecologist
Artist bio, works, shows and exhibitions, Zaria Forman on Artsy

The history and exploration of France’s Mer de Glace (‘Sea of Ice’) is fascinating, and it’s become an important fresh water source as well as a popular tourist destination. Sadly, it’s also disappearing.

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·Feature photo is a still shot taken from the Zaria Forman Ted Talk video
·Glacier Map, courtesy of NASA Earth Observatory, is a visual depiction of world glacier study and catalog by the Randolph Glacier Inventory (2014)
·Graphic:  Dramatic Glacier Melt (Muir Glacier, 1941/2004), NASA Climate 365