Those tumbling blocks of blue-white ice spilling down a mountainside are not just nice to look at and an attraction for tourists but vitally important for the environment.
By Paul Gorman
It’s largely been bad news for glaciers during the past couple of decades. As recently as the early 1990s, alpine glaciers were still advancing from their accumulating snowfields higher up.
However, since then, the malign influence of climate change has made itself felt, putting glaciers into retreat across most of the world.
Glaciers act as water towers
The loss of ice from glaciers and the steady withdrawal of their terminal snouts back up the mountains is one of the most visible effects of the changing climate. According to the International Atomic Energy Agency, more than 200 billion tonnes of ice are melting from glaciers around the globe every year.
This depletion to the cryosphere is something Seequent Segment Director, Environment, Dr Thomas D. Krom is watching with concern.
“Glaciers function as water towers in the hydrologic cycle for billions of humans, storing winter precipitation and releasing it during warmer months for irrigation and drinking water.
“Climate change is rapidly accelerating glacial retreat, threatening essential water supplies across the globe,” he says.
Glacial melt is an essential nutrient source
The continued dwindling of glacier ice has a number of other worrisome impacts on human activities, the environment and ecosystems. Runaway melting would be disastrous.
As well as releasing freshwater for the drier months, glacier meltwater is a source of nutrients for plants downstream, with high concentrations of essential elements such as iron, zinc and manganese, collected by the ice as it scrapes across the mineral-containing rocks below.
Bouncing sunlight back to space
The white icy surfaces of a glacier are actually doing their bit to minimise the warming climate. With their high albedo (a measure of light reflection) they bounce sunlight back into space, helping to moderate and regulate temperatures. The loss of ice mass means less sun is reflected and more heat can be absorbed by the Earth.
How rivers of ice hold back erosion
Glaciers form many of our landscapes as they scour away rocks and slopes, and deposit sediments lower down in the deep U-shaped valleys they form.
Ironically, though, the very existence of these eroding glaciers within their carved valleys helps reduce other forms of weathering. Remove the ice body and it is easier for rock formations on the sides of the valley to crumble, slip and slide, on various scales from insignificant to major mass movement, to the valley floor below, further changing the look of the alpine environment.
Lastly, glaciers look incredible. They are a source of pride to locals and a great attraction for international tourists, which helps boost regional economies. People climb on them, paint them, photograph them.
The world would be much poorer without glaciers, another reason for us to do as much as we can to hold back galloping climate change.
Dr Greenbaum and his team want to understand what is driving Antarctic Ice Sheet melt and how to better predict global rising sea levels.