I don’t know about you all, but I think glaciers are pretty cool. While in New Zealand with my family, we visited the Franz Josef glacier on the west coast of the South Island. I had so much fun climbing like a mountain goat over the ice and looking at the beautiful blues and turquoises it creates. Not many people get that chance and some may be wondering what exactly is a glacier?
Glaciers are large ‘rivers’ of ice that are formed from years of snowfall that is compacted into ice. They can only form in places where snow stays on the ground year-round and can take hundreds of years to develop. The oldest known glacier, found in Antarctica, is about 8 million years old; the youngest glacier is Crater Glacier on Mount St. Helens which began forming in 1980.
As snow is layered on snow it gets squeezed together (like when you make a snowball) and forms small ice crystals. These crystals get compacted, and more and more air is pushed out of the forming ice. Eventually, this build-up puts some much pressure on the ice below that it starts to slide downhill. (Check out How Glaciers Move)
The zone of the glacier where this build-up occurs is called the accumulation area (makes sense, right?). As the glacier flows downhill, it reaches a point where the surroundings are warm enough to melt an evaporate the ice at that leading edge. This is called the ablation area. When there is more accumulation than ablation, the glacier advances or moves forward/”grows”. When there is less accumulation than ablation, the glacier retreats or ‘shrinks’. Measurements of how much glaciers retreat over the years is some of the data used to provide evidence for global warming and climate change. Chasing Ice is a wonderful film that captures the dramatic glacial changes in the Arctic.
It’s ice, so what? Glaciers have more of an impact around the world than many would think. First off, glaciers can dramatically change the geography of an area. The advance and retreat of glaciers during the last ice age formed the Great Lakes in North America. Yosemite National Park contains several steep valleys created by glaciers, and a similar process created fjords now seen in Norway, New Zealand, Alaska, the tip of South America, Canada, and more.
Second, many people rely heavily on meltwater from glaciers for irrigation and drinking water. Glaciers in the Himalayas provide water to people throughout Asia, especially India and China. So what would happen if these glaciers melted because of global warming? These people that need water from glaciers would have more of it, that’s good, right? But what happens when there is too much water melting from the glaciers… flooding. So as the glaciers melt, you would start with just a little more water… then more and more until the glacier is entirely melted. That means that there is no water left to be melted and used for irrigation and drinking, and that leads to drought.
This is why so many scientists are concerned with ice, and what I talked about here is just glaciers. There is much more to ice and what would happen to the world if there was no more ice. So keep coming back to learn about why we’re all obsessed with ice, ice, baby!