Recently, scientists were surprised to find that the glaciers in the Central Karakoram mountains rising rapidly. And it's not about "spreading" of the ice cover. A rise in full — the thickness of the glacier at the same time also increases. And despite the fact that there, in the Himalayas, the ice continues to melt. What is the reason Karakorum ice anomaly?
It should be noted that, given the global trend to reduce glaciers situation is quite paradoxical. Mountain glaciers in Central Asia were "white crows" (in both senses of the expression), because their area is growing at the same rate as the decrease in other places. Data received from Karakoram from 2005 to 2010, completely baffled glaciologists.
Let me remind you that the Karakoram, located at the intersection of Mongolia, China, India and Pakistan (between the Pamirs and Kunlun in the north and the Himalayas in the south Transhimalaya), is one of the highest in the world. The average height of the rocky ridges of the mountains is about six thousand feet (which is greater than, for example, in neighboring Tibet — where the average height of about 4880 meters). There are also several "Eight" — the mountains, whose height from the bottom to the top of more than eight miles.
Not surprisingly, the glaciers in the mountains — a real expanse. Glaciation area, as of the end of the twentieth century, was about 15 square kilometers in 4000. It is believed that the Karakoram has the largest reserve of ice temperate latitudes around the world. The boundaries of the snow line in the mountains are in the south-west at an altitude of 4600-5000 meters, in the north — at altitudes of 5000-6000 meters, and in the north-east it rises to 6200-6400 meters
Interestingly, in the last century, many Karakoram glaciers area declined slightly (for example, Baltoro Glacier in the period from 1928 to 1958, stepped across the board by about 500 meters). However, the 70 years of their condition stabilized. Until the end of the century no one really knew what was going on with the Karakorum ice because there had been no systematic research. However, when in 2005, glaciologists to take them back to back, they gasped in surprise. And, in fact, the reason was.
The fact that, according to satellite and field studies, the Karakoram glaciers in the time as long as they do not engage in, very, very grown up. Now, their area is about 16 square kilometers in 3000. And despite the fact that in the neighboring Himalayas, for example, a reverse process — there is ice cover, on the contrary, greatly reduced. Last scientists link to global warming. Atmospheric temperature rose, and ice, respectively, is melting. But how to explain these positions that close at the same general increase in temperature increases the glacier?
At first, researchers thought that perhaps the effect of growth apparent. They suggested that in fact the Karakorum ice does not grow, but just "away" on the slopes (as sometimes happens, the thickness of the ice is reduced — the glacier just breaks under its own weight and crawls down). Therefore, in order to test this hypothesis, "wrong" glaciers come to grips with a team of researchers led by Julie Gardel from the University of Grenoble (France).
Scientists analyzed the thickness of the ice on the area of 5615 square kilometers, by comparing data from instruments of the space shuttle "Endeavour" in February 2000, and the French SPOT5 satellite in December 2008. After accounting for differences in the orbital path of the two vehicles and different time of the year (among other factors) the researchers found that about any of the spread of the question.
Glacier really "fatter", and fairly. According to scientists, every year from late 1999 to late 2008, they "put on weight" on average the equivalent of around 11 centimeters of water (that is, if all this water to melt the flat surface of the same area, you get the depth of the lake at 11 centimeters) .
Indirect evidence of the growth of glaciers is also a condition of local rivers. The fact that in this region they are fed by meltwater flowing down from the glacier. So, on average, all the rivers in the study area has shoaled by 20 percent from that of the late twentieth century. Consequently, the melting of ice slowed the glacier that is growing.
Why did this happen? While researchers have not been able to give a clear explanation. There was only a hypothesis that glaciers protect from heat thick clasts (they raze the mountain avalanche), which tends to Karakorum just littered. Breed, indeed, may serve teploprotektorom, but this is unlikely to explain the phenomenon of Karakorum — because in the neighboring Himalayan debris no less, and yet the glacier melts.
Apparently, it's quite different. Glaciologists have long established that the growth of ice is not directly dependent on the temperature fluctuations (in particular, the father of the author of these lines, Vyacheslav P. Evseev issue devoted a lot of his work). But there is a direct relationship with the thickness of the ice sheet total precipitation. Simply put, the glacier is formed not where cold, and where there is a lot of snow in the winter and in the summer it does not have time to melt completely.
High in the mountains, there is just such a situation — the temperature difference in summer and winter is not sufficient to precipitate in the cold snow has melted completely. Well, when the snow accumulates, it is compressed by its own weight, forming a first neve (dense snowdrift like those we see on the streets in March — in places where the winter wipers dumped snow from sidewalks), and then — block of ice.
Furthermore, this block is actively begins to reflect the sun's rays, which further complicates its melting in the summer. There is a positive feedback loop, whereby the thickness of ice each year is growing rapidly. In the end, the bottom of its fibers under intense pressure, start to allocate water, and all the ice, sliding on it, crawling down like a skater at the rink. Accordingly, the area of its distribution also depends on the thickness and, consequently, the amount of winter precipitation.
So in the Karakoram, according to meteorologists, from the end of the twentieth century became very heavy snowfalls. Now there they fall about 1200-2000 mm per year, almost all in a solid form. And the average annual temperature is still the same — in the range of five to four degrees below zero. Not surprisingly, the glacier began to grow very quickly.
At the same time in the neighboring Himalayas, according to forecasters, for the same years, the snow began to fall substantially less. Glacier these mountains was deprived of its main source of food and, accordingly, "cringe." It is possible that the point here is to change the path of following air masses of snow — before they go to the Himalayas, and now turns to the Karakoram. But in order to confirm this hypothesis, it is necessary to check the situation with glaciers other "neighbors" — the Pamirs, Tibet, Kunlun and Transhimalaya
However, scientists are going to do it so, as research conducted at Karakorum, are part of the long-term study 46 glacial mountains of Central Asia. And then with the Karakorum "anomaly" will become abundantly clear. So far we can say that the situation of the glaciers in these mountains caused very sev
ere blow to the modern theory of global warming — it turned out that he can accompany and local cooling. That is, the protective system of our planet from a runaway temperature increases are, they work well …