All climbers love rocks, fact. But without ice, many rocks would either be boring shapes, or even non-existent. In fact, we might not even be here if it weren’t for glaciers. So strap on your viewing goggles, pull up a pew, and find out why glaciers are so chillingly important.
1: They will eat you
Let’s be honest, this is the most obvious feature of glaciers, and the rest of the article doesn’t matter a sh*t if you’ve been swallowed by a crevasse. I would guess that most (all?) people who set foot on a glacier are aware of this danger, and spend a reasonable amount of effort avoiding these giant cracks (Image 1).
But what are they doing there? Crevasses typically form along the margins of the glacier, at its head, and on steeper terrain form in response to the movement of the ice. In their upper sections, crevasses form perpendicular to the direction of travel, whilst in the lower regions they are commonly parallel to the valley walls. Whilst many crevasses are only 20-30 m deep, they are still deep enough to die in. If you are unlucky enough to find yourself in a pool water at the bottom of a crevasse, it’s likely that the crevasse will also be deeper, since the pressure exerted by the water prevents the crack from closing. Double bad luck.
Rest assured you will always find your way out of a crevasse. But it may take some time – bodies have been entombed within glaciers for thousands of years. Frozen within the ice, the bodies are slowly transported with the creaking, sliding ice towards the glaciers’ downhill termination*. And when global warming does its’ job (more on that later) and the ice melts, all sorts of gruesome discoveries are made (check out this article from The Guardian).
2: They give us good boulders
Glaciers aren’t the just preserve of trad climbers and snow yompers. Even the beanie-clad boulderer, who daren’t venture far from the road, can enjoy the products of glaciation. Because yes, like a rock-eating power lifter, glaciers can carry big boulders inside them, beneath them and on their top.
Now, you’re going say “Oh yes, heard this one before – glacial erratics”. But wait. Not all boulders are erratics. This term is reserved only for boulders carried by glaciers and composed of a contrasting geology to the surrounding area. Say, a gritstone boulder in an area of crappy mudstone (check out the Great Stone of Fourstones). And not all boulders fit this bill. Some instead are of the same geology as the surrounding area, and have just been plonked as the glacier melted (check out the Columbia Boulder and its’ neighbours). These are given the Ronseal** name of “glacially-transported” rocks. But that’s fine, we needn’t split hairs. Regardless of their origin, glaciers are conveyor belts that deliver rocks to roadside locations. Win.
3: They give us context for our own experience
Let’s get deep with this one. Glacial periods have occurred throughout geological time. At several periods in Earth’s history glaciers, ice caps and ice sheets have extended pretty much across the entire of the Earth’s surface. From space, Earth looked more like a giant snowball (or slushball, depending on how much water there was) than a blue planet. Evidence for these mega glaciations can be found in the most unlikely of places, including the Sahara and outback South Australia. Evidence for this is provided by features including striations (Image 2) and the fine grained, muddled sediment (called till) typical of glacial regions. Contemplating the enormity of these glaciers and the millions of years they took to form puts your split tip into perspective.
4: They make good crags
OK so you’ve never set foot on a glacier. Who cares? There’s lots of glacial features to enjoy here at home (Image 3). Dow Crag, Stob Coire an t-Sneachda and Idwal Slabs are all the products of glaciation. They are found in bowl shapes known as corries, cwms or cirques (their name varies in different countries). Corries represent the starting point of glaciers and are formed as rocks became frozen into the glaciers’ bases, and were plucked from the hillside as gravity exerted its irresistible pull. On top of this, glaciers act like a giant ice cream scoops – rotating and scouring the bedrock below. Through a combination of these processes and chemical weathering, the corries and their crags were quarried from the hillside.
5: They stop the Earth getting too hot
Glaciers are like giant mirrors. They reflect solar radiation back into the atmosphere and beyond. This is great for us in a sense, as the presence of glaciers at high latitudes and altitudes means that the Earth remains cooler than if they weren’t present. In turn, this stops us and our crops from drowning beneath the rising seas. The bad news is, the melting of glaciers is a runaway effect. The more glaciers melt, the less reflectivity, the hotter the Earth, the more glaciers melt, and so on.
6: The scenery
The majesty of glacial valleys has inspired generations of climbers and outdoorsy folk. John Muir was one such disciple, who was the first to recognize the Yosemite Valley (Image 4) as the product of ancient glaciations. He believed wild places had intrinsic worth, leading him to campaign for the creation of the Yosemite National Park. And so Muir’s knowledge and experience of glaciated landscapes acted as a catalyst for environmental protection.
7: Without glaciers, we might not exist.
660 million years ago, the Earth was covered with ice (see point 3). As you can imagine, being in a giant freezer is pretty hard on life, and many ecosystems were ravaged. Temperatures were exceedingly cold and the ice cover prevented sunlight penetrating the ocean. But when the ice melted, the creatures that had weathered the storm had the opportunity to evolve and diversify into a spectacular array of life. Thus, multi-cellular life got a foothold, and from these humble beginnings we eventually crawled.
8: They show us what we’re doing to the world
Not all glaciers are retreating. But the sad news is, most of them are. Even sadder is the fact that their retreat is partly (largely?) due to us. By analysing ancient air bubbles frozen into the glaciers, we are able to reconstruct the composition of the atmosphere and temperatures from 800, 000 years ago. Time and again, the conclusion is that our climate is warming at an unprecedented rate. But you don’t need tiny bubbles and fancy microscopes to understand that our climate is changing and glaciers are retreating. Take a look at the Mer de Glace and see for yourself. Just don’t get all Trump with me. The question isn’t whether anthropogenic climate change is happening, it’s whether you care enough to do something about it.
9: They give us scrambles.
Classic scrambles and alpine routes follow arêtes. These features are the result of two glaciers separated by a rocky ridge flowing side by side. They form the arms of the chair where glaciers once sat (Crib Goch and Striding Edge being great examples). The arêtes found here in the UK are more subdued than those found in the Alps, simply because they’ve had several thousand years of upland weather nagging them.
10: They are an essential ingredient in our experience of, and attachment to, alpine and polar environments
Standing in the Sahara desert or the Amazonian rainforest is a very different experience to being in the French Alps. A large part of this difference results from the features of the natural world. Alpine environments lure us with their otherworldly whiteness and black, looming peaks framed against a cobalt blue sky (Image 5). Crunch, crunch; as you step across the snow, breathing heavily and sweating across your back. The wind in your ears and gentle tugging on your waist as the rope pulls and your partner stomps on. Without glaciers, risk would be diminished and the high mountains would loose part of their appeal. Just don’t get eaten.
*Like some feral beast, this region is referred to as the glaciers’ “snout”.
**Does what it says on the tin