I confess: I have sinned. This summer I flew on a plane, exacerbating the climate crisis, and I found myself in the Mont Blanc massif in France. I succumbed in a vile and miserable manner to last-chance tourism. And all of this to witness the melting of the glaciers as a result of global warming. The feeling I brought back with me? A lingering sense of unease that is difficult to appease.
Glaciers, more than just masses of ice
Although I had seen and photographed them from a distance, I had never before had the opportunity to get close or walk on a glacier. And I assure you, the sensation of coming face-to-face with a massive block of ice that creaks, cracks, and moves slowly is difficult to put into words.
Glaciers are not just magnificent indicators of climate change. They are also crucial water reserves for many regions of the world. In fact, they store around 69% of the world’s freshwater (1).
For example, the Emosson Dam in Switzerland, used for hydroelectric power generation and providing drinking water, is partially fed by the glaciers of Argentière, Le Tour, and Lognan in France.
But before analyzing the current situation of the glaciers, I want you to accompany me back to school to refresh some knowledge about glacial morphology.
What are alpine glaciers?
An alpine or mountain glacier is a mass of ice that forms on the Earth’s surface and moves slowly downhill.What are alpine glaciers?
The basic parts that can be distinguished are:
- Accumulation zone, which occupies the higher area where the snowfall accumulates throughout the year.
- Ablation zone, the lower area where processes of evaporation, melting, or fusion occur.
- Crevasses, locations where the ice breaks due to the speed at which the glacier flows.
- Moraines, which are the rocky debris and sediments that the ice carries in its movement. They can be observed at the top (central moraine), along the edges (lateral moraines), or at the end of the glacial tongue (terminal moraine).
How a glacier forms
A glacier begins to form when the snow stored in the accumulation zone persists for a long time. This preservation allows for its compaction and recrystallization as new layers are added. The transformation of fresh snow takes at least one year, although it can extend for much longer. The weight of the ice, its deformation, and the force of gravity do the rest, causing the glacier to start flowing downhill.
Under normal conditions, these ice masses maintain a balance between accumulation and ablation processes. However, when this stable situation is disrupted, the glacier advances or retreats at a faster rate than normal (2). In other words,
- if melting or ablation increases due to rising air temperatures, for example, while accumulation remains stable, the length and surface area of the glacier decrease (which is more or less the current situation).
- if accumulation increases due to higher snowfall and ablation remains stable, the glacier grows.
Glaciers are melting, a terrifying story in four words
Please, don’t be deceived. It is easy to find news on the internet about growing glaciers. But these are isolated cases or exceptional situations that have their own explanation. One example is the “Karakoram anomaly” (3) in the border region between India, China, and Pakistan.
In general, glacier retreat is a global trend that has experienced a dramatic acceleration since 1990 (4). Today, glacier melt accounts for about 30% of the current rate of sea-level rise (5).
And in few places is the effect as evident as in the Mont Blanc massif.
Mer de Glace, a glacier melt measured in staircases
The Mer de Glace, or Sea of Ice, is the longest glacier in France, stretching for about 7 km and reaching a thickness of around 200 meters. Its path winds among sharp rocky peaks that exceed 4000 meters in altitude.
The main access point is the Montenvers railway, a cogwheel train from the early 20th century. And as you can see in the image, back then you only had to take a few steps to descend to the glacier.
But since 1909, the thickness of the glacier has reduced by about 100 meters, and by the year 2040, its length is estimated to decrease by about 1200 meters.
One of the clearest signs of this change is the addition of new staircases every year to access the ice cave, a tourist and educational attraction that has been excavated since 1946 in the glacial tongue.
In August 2019, reaching its entrance involves:
- descending a section by cable car;
- going down approximately 480 grid stairs connected by ramps, and
- walking on an open walkway over the ice, covered to prevent slips.
In fact, the entire entrance of the cave is protected with textile material to prevent it from melting during the time it is open to the public.
During the descent (and subsequent ascent), you can observe plaques that indicate how far the ice extended.
The first impression that overwhelmed me was one of disbelief, to the point of doubting the correct placement of the plaques.
When you reach a marker that says “Ice Level 1990” and take a look at the dozens of meters that still remain to reach the cave entrance, you conclude that it is impossible for the glacier to have thinned so drastically in just 30 years.
So that night, I dedicated myself to research, and yes, I discovered how mistaken I was.
An undeniable evidence
One of the most striking articles is the one published by Helene Fouquet in Bloomberg, recounting her visit to Mer de Glace in 1988 and the changes she observed when she returned in 2015. And, in particular, the diagram it includes.
Created using data from the USGS Earth Explorer and Christian Vincent, a glaciologist from the University of Grenoble, it shows where the cave entrance was located between 1988 and 2015. It also shows how many sections of stairs and ramps had to be added (you can see the diagram, titled “Glacial retreat,” in the following tweet).
As you can see, only from 2015, the date of the article, to this year, 2019, over 100 stairs have had to be added. And it’s worth noting that in the period from 2014-2015 alone, the glacier lost nearly 4 meters in thickness, compared to an average annual loss of one meter over the previous 30 years.
Imagine how many more steps will be necessary in 2020 after a summer that has recorded record temperatures.
Technology to keep hope alive (for now)
More than 100 years have passed since Swiss photographer Eduard Spelterini flew over the Chamonix Valley in a hot air balloon with his camera in hand to photograph the Montblanc Massif. His spectacular images are now valuable documents that reveal the extent of the retreat that the ice masses in this area of the Alps are experiencing.
Technology has made impressive advancements. Now we have satellites, drones, and snow measurement sensors like those from Smarty Planet at our disposal, allowing for unimaginable monitoring that was not possible just a few years ago. In fact, many alpine glaciers, such as the Argentière Glacier, are dotted with sensors that scrutinize and record every small change.
And the data recorded over the past decades (for climate analysis, a recommended period is about 30 years) do not lie: glacier melting and, consequently, global warming are unequivocal.
Warm up, it’s time to play
The Earth’s climate, like glaciers, has changed substantially, but it has done so at its own pace, gradually varying over thousands or tens of thousands of years (except for some abrupt changes like the Little Ice Age between 1550 and 1850).
The progressive adaptation to new climate conditions that species inhabiting the planet require becomes more complicated when these modifications gain momentum and become noticeable on a human timescale.
We have the information, technology, and knowledge necessary. We only need to start acting decisively, not only to reverse or prevent climate change, which I believe is already impossible, but to minimize its most catastrophic consequences.
The only shudder in a glacier should be the cold felt from being near an enormous freezer, not the unease caused by witnessing a marvel crumbling like a sugar cube.
Sources consulted:
- (1) National Snow and Ice Data Center (s.f.). All about glaciers. Web consultada el 02/09/2019. https://nsidc.org/cryosphere/glaciers
- (2) European Space Agency (s.f.). La dinámica de los glaciares. Web consultada el 02/09/2019. https://www.esa.int/SPECIALS/Eduspace_Global_ES/SEM4OL22ECH_0.html
- (3) N+1 (07/08/2017) Aquí, los glaciares no se derriten, sino crecen: revelada la paradoja de Karakoram. Web consultada el 02/09/2019. https://nmas1.org/news/2017/08/07/glaciares
- (4) Enríquez de Salamanca, Á. (2011). El ocaso de los glaciares. Revista Foresta, (53), 46-54. http://www.redforesta.com/wp-content/uploads/2012/07/CT2-El-ocaso-de-los-glaciares.pdf
- (5) Science Alert (11/04/2019) Graphic shows the true scale of world’s glaciers disappearing at record speeds. Web consultada el 02/09/2019. https://www.sciencealert.com/fresh-water-supplies-melt-away-as-world-s-glaciers-lose-335-billion-tonnes-of-ice-a-year
- (6) Fouquet, H. (25/09/2015) Want to see climate change? Come with me to the Montblanc glacier. https://www.bloomberg.com/news/features/2015-09-25/climate-change-on-mont-blanc-the-vanishing-mer-de-glace
- (7) Mer de Glace loses 3,61 metres in depth (10/11/2015). Chamonix.net. https://www.chamonix.net/english/news/mer-de-glace-lost-3-61-metres-depth
- (8) Baxter, K. (15/03/2018) What a century of climate change has done to France’s biggest glacier. The Conversation. https://theconversation.com/what-a-century-of-climate-change-has-done-to-frances-biggest-glacier-93248
Judit Urquijo
Técnico ambiental, community manager y content curator especializada en la relación entre medioambiente y tecnología