From the school curriculum, everyone knows that water can be in three states of aggregation - solid, liquid and gaseous. Solid water is ice. But not everyone knows that ice can be different and even have the property of fluidity. It is this type of ice, glacier, that will be discussed in this article.
So different
Today, three types of amorphous ice and 17 crystalline modifications are known. According to the degree of development, it is of the initial stage (intrawater, needles), young (flasks and nilas, gray and white), perennial or pack. By its location, it can be motionless or frozen to the coast (fast ice) and drifting.
According to its age, ice is spring (formed before summer), one-year and multi-year (there are more than 2 winters).
But there are many more types of ice by their origin:
- Atmospheric: frost, snow and hail.
- Water: bottom, intra-water, integumentary.
- Underground: vein and cave.
- Glacier ice is a type of ice that forms glaciers on our planet.
Glacial
Glacier ice is that which forms from snow above the snow line. This is a special ice that consists of transparent bluish large crystals, the axes of which acquire a certain orientation over time.
Glacier ice is characterized by the presence of stripes. This is due to the processes of its formation. In addition, an important property of glacier ice is its fluidity: under the influence of gravity and its own pressure, glacier layers move along the surface. At the same time, the speed of such movement is different: in the mountains, glaciers move by 20-80 cm per day, and in the polar zones, the speed of their movement is from 3 to 30 cm per day.
How it is formed
The process of formation of glacier ice is quite complex. In short, the snow that falls in glaciers compacts over time and turns into firn - opaque and granular ice. The pressure of the upper layers of snow squeezes air out of the firn, and its grains are soldered. As a result, a transparent and blue mass of glaciers is formed from an opaque white firn - this is glacier ice (the photo at the beginning of the article is the Knick Glacier in Alaska).
The peculiarity of glacial ice is the absence of stratification, constant fluidity and huge mass (1 cubic meter of snow, for example, weighs up to 85 kg, firn - up to 600 kg, and glacial ice - up to 960 kg).
Why does it flow
Glacier ice is plastic, which explains its ability to flow. The pressure of the upper layers (accumulation zones orglacier supply) lowers its melting temperature, and melting begins at temperatures below zero degrees. Thus, the lower layers (ablation or flow zone) begin to melt, and the resulting water is a "lubricant" for the movement of the upper layers of ice.
If the movement is small, the water freezes again. But in another place the same process takes place, and in general the ice mass is constantly flowing. At the same time, in a glacier, ice flows from places where it is thicker to a place where it is thinner - from the center to the outskirts.
At the same time, glacier ice breaks and cracks. When accumulation prevails over ablation, the glacier advances. And vice versa. And that is why streams and even rivers continue to flow from some glaciers throughout the winter.
Stock of fresh and clean water
During the formation of glacial ice, all impurities are squeezed out of it, and the water that forms it is considered the purest. Glaciers on our planet occupy 166.3 million square kilometers of land (11%) and accumulate 2/3 of all fresh water on Earth, which is about 30 million square kilometers.
Almost all of them are located in the polar region, but there are also in the mountains, and even on the equator. Greenland (10%) and Antarctic (90%) glaciers in some places descend to the waters of the oceans. Pieces that break off from them form icebergs of glacial ice.
Global warming and glaciers
Recent studies by scientists have shown that the rate of ice melting has increased 3 times over the past five years. And thisThis means that in the coming decades, the melting of glaciers could lead to a sea level rise of 3.5 meters by 2070. But this is not the only problem in this aspect.
In addition to changing ecosystems and reducing biodiversity, this promises us desalination of the world's oceans and a shortage of drinking water. But there are also some rather unexpected consequences of their melting.
The melting of glaciers can change the climate on the planet. And there are many examples of this. So, once the Tien Shan (China) was called the "green labyrinth" - the water of the glaciers was enough for the development of agriculture. Today it is a dry area.
And even if hydropower wins in the short term, it will become completely useless in the long term. The tourism industry will also suffer, and ski resorts will be the first to feel it.
In conclusion
Global warming and melting ice is quite comparable to the end of the world. And this, according to experts, has led to human economic activity. And we have only one way out - reducing greenhouse gas emissions.
It's good that humanity understands this, and since 1992 the world has adopted the concept of sustainable development, which combines scientific and technological progress, economic growth and biodiversity conservation.
