Vanishing Glaciers
More melting ice…
When I grew up in Germany, summers were cold and rainy, unlike now. During the 1960s schools from first to 13th grade (yes, if you wanted to study at a university you had to complete 13 grades) offered only four weeks of summer vacation. Which caused terrible freeway congestion because every family with school age children would drive south, to Italy or Greece or wherever people could find some sunshine and warmth.
Because my mother was born in Austria, this was my parents’ favorite vacation destination. To get there, one had to cross the Alps, and the way to Wörthersee, the lake where we always stayed, leads across the Grossglockner Pass, a high alpine road with lots of hairpin curves. I remember the many stranded cars that littered the curb; their motors were overheating, with opened hoods, and clouds of steam visible. Reaching over 8,000 feet, the passage belongs to the highest paved roads in Europe.
We always stopped at a popular visitors’ center, the “Kaiser-Franz-Josefs-Höhe”, from where one has a fantastic view of the Pasterze, Austria’s largest glacier. I was in awe of the sight of this gigantic frozen river of ice.
What a glacier consists of, how it was formed, why it could move – I had no idea then, and I must admit that the many years since these long-ago visits have added little to my knowledge. It’s high time to correct this, so – please bear with me while I share what I’ve learned.
A glacier starts high up in the sky with snowfall, consisting of many snowflakes, each of which begins with a tiny ice crystal – the seed from which a snowflake will grow. As the snowflake falls through different atmospheric temperature and humidity zones, its six arms or sides continually change and grow, while preserving its unique character: no snowflakes are alike, because of the estimated 1019 (10 quintillion) water molecules which make up a typical snowflake.
The two kinds of glaciers – alpine or mountain glaciers such as the Pasterze, and continental glaciers which are massive sheets of ice which cover land masses – were formed by fallen snow which was compressed into ice over many centuries. The compression of lower layers from continuing snowfall above changes the snow crystals: as the air gets squeezed out, the snow recrystallizes and forms larger and larger grains which become round. One crystal can be the size of a fist in very old glaciers.
The two existing continental glaciers or ice sheets, one that covers most of Greenland, and the other one which spans across the Antarctic continent, are leftovers from a series of Pleistocene Ice Ages when much of the Northern Hemisphere was covered by ice. Global temperatures have been rising for the last 25,000 or so years, but the production of greenhouse gases (mainly carbon dioxide and methane) results in glacial ice melting at rates higher than ever before.
And why do glaciers flow, like slowed-down rivers? As the graph above shows, the ice crystals of the deeper layers change and deform because of the pressure from the enormous weight above. This actually causes the ice along the base of the glacier to melt, which in turn causes it to slide.
The Pasterze, the glacier that had impressed me so much when I was a kid, has changed considerably since I last saw it. Compare these two photographs:
The top one is from a postcard from circa 1900, the bottom one a photograph taken in 2009 at the same location. It illustrates how much the ice has receded.
This is happening to all glaciers and other ice masses, as the graph below shows. If you’re curious about the retreat of glaciers since 1850, you can read it here.
Last summer my daughter went to Liechtenstein as a volunteer leader for a hiking trip in the Alps, offered by the Appalachian Mountain Club. I believe they hiked to the Zumstein Spitze, part of the Monte Rosa Mountain Massiv near Saas Fee in Switzerland. When I saw the pictures she took, I was struck by the intense turquoise blue of the waters that came from a near-by glacier. I couldn’t find its name, but will share a photo. One can only hope that we humans will manage to save glaciers from extinction.
There is a slight chance that this is possible. Two days ago, Kate Marvel, a climate scientist at the environmental nonprofit Project Drawdown and lead author on the Fifth National Climate Assessment, wrote an opinion piece for the New York Times: “I’m Not Screaming Into the Void Anymore”. She wasn’t happy that all their predictions about extreme events had come true and was reluctant to submit another collection of dire warnings. But the latest of the National Climate Assessments which are published every four years actually surprised her: there had been progress. While there were plenty of worrisome outcomes if the world warms by another 2 degrees Celsius, there was some hope. Emissions COULD fall dramatically.
I’ll leave you with this optimistic glimmer. My opinion that we need a drastic reset, a massive paradigm shift, hasn’t changed and Ms. Marvel’s article certainly doesn’t invite complacency. But fear and anxiety aren’t called for, either.
A glimmer of hope...