Essay on the Retreating Glaciers | Geography

Read this essay to learn about the retreating glaciers.

A new Iceberg, named C-19, has broken away from Antarctica and floating next to Antarctica Ross Ice Shelf. The Iceberg is named C-19 because it is the 19th new berg reported in that section of Antarctica since records were first kept in 1976. It measures 124 miles long and 19.5 miles wide, or 2,428 square miles.

The report of C-19 comes less than a week after C-18 broke free in the same general area; it was 47 miles long and 4.6 miles across. In March, another giant berg broke free in adjacent area. Named B-22, it measured 2,120 square miles. Also in March, a large floating ice shelf in Antarctica collapsed. The 1,250 sq. miles section of the Larsen Ice Shelf splintered into a plume of drifting icebergs during a five-week period that ended March 7.

The largest freshwater storage on the earth is represented by the glaciers. It has been estimated that 2.15% of the world’s total water is frozen in ice as glaciers. If all this ice was suddenly to melt, the sea level rise will be 60 to 90 meters. The existing glaciers cover over 16 million square kilometres, which is about 11% of the land surface. Total volume of ice and perennial snow in all the glaciers is estimated at 27-30 million cubic kilometres.

Contemporary glaciers are developed in all the mountains plains of various climatic zones, where temperatures and large amount of hard atmospheric precipitations are found to combine. Glaciers also cover continents and many islands in the southern and northern polar countries, of which the largest is Antarctic ice cover occupying 95% of the whole continent and the adjacent islands, or approximately 13.9 million sq. km.

The Greenland glacier covers about 1.8 million sq. km. surface. The area of all the other Arctic and mountain glaciers comprises on the whole about 0.5 million sq. km. The average thickness of the Antarctic glaciers is 2,000 meters, while the maximum recorded thickness is 4,200 meters.

Although most of the world’s ice is locked in two great ice sheets covering Antarctica and Greenland, nearly 17,000 glaciers covering 17% of the Himalayan region claims a fair share. Some of them are tens of hundred meters thick and 3-5 kilometres long.

Most of them form above the permanent snowline around 4,900 meters. This is the largest body of ice outside the Polar Caps, and forms a unique reservoir which supports mighty perennial rivers such as the Indus, Ganga and Brahmaputra, lifelines of millions of people.

An abiding concern of climatologists faced with the prospects of global warming has been the behaviour of the great ice sheets. The world has become warmer over the past hundred years and many scientists ascribe this to increase in greenhouse gases in the atmosphere.

It seems likely that a warmer world will melt the glaciers. Lonnie Thompson, a geologist with Ohio State University, points out that no tropical glaciers are currently known to be advancing. He also predicts that many mountaintops will be completely melted within the next 20 years.

With the end of the Little Ice Age (1430 to 1850), glaciers have been retreating with the rise in atmospheric temperatures. In the last hundred years alone, the global mean temperature has increased by about 0.5 to 1.0°C, and the rapid receding of glaciers to a major extent, is a consequence of global warming.

Many climatologists believe that the glaciers are decaying at rapid, catastrophic rates; its total area will shrink from the present 500,000 to 100,000 square kilometres by the year 2035. Societies located close to glaciated areas, which are dependent on the melt-water for primary production, are very vulnerable to changes dynamics of the glacier. The dramatic projection is realistic due to the positive feedback mechanisms between rainfall and glacier size.

Decreasing glacier may indirectly cause less rainfall since the amount of summer rains is partly dependent on the cooling effect from the glaciers. This will reduce albedo from the ice which will again lead to higher temperatures and more melting ice. The glaciers in central and east Himalaya are only fed by summer precipitation, thus the relationship between size of the glacier and precipitation is stronger than glacier which also accumulate in the winter.

According to the International Commission for Snow and Ice, “glaciers in the Himalaya are receding faster than in any other part of the world, and if present trend continues, the likelihood of them disappearing by the year 2035 is very high.” Many Himalayan glaciers, including Gangotri, are known to be receding for the past several years. Records of retreat of Himalayan glaciers indicate that Pindari glacier is retreating at the rate of 135.2 meters/year, while for Gangotri the rate is 28 meters/year.

No tropical glaciers are currently known to be advancing. Africa’s Mount Kilimanjaro has lost 82 percent of its ice field since it was first mapped in 1912. At the current rate of melting, the snows of Kilimanjaro will be gone within 15 years. The largest glacier on Mount Kenya lost 92 percent of its volume in the past century. The Quelccaya ice cap, the largest in the tropics, has shrunk 20 percent since 1963. One of Quelccaya’s main glaciers, named Qori Kalis, is retreating at a rate of almost a half-metre per day.

The phenomenon is not confined to the tropics. Glaciers in Europe, Russia, New Zealand, and the United States are also melting. With more than 1000 glaciers, Alaska is warming faster than most areas. In the past two decades the massive Columbia glacier has retreated more than 12 kilometres. Scientists estimate that by 2025, the Swiss Alps will have lost about 90 percent of the volume of ice that was there a century ago.

The extent of spring and summer sea-ice in the Arctic has decreased by about 10 to 15 percent since the 1950s. The Glacier National Park, Montana, has more than 50 glaciers, but will probably lose all of them by 2070. The annual duration of lake and river ice in the middle and high altitudes of the Northern Hemisphere has dropped by about two weeks. In Russia, the imposing glaciers of the Caucasus Mountains have shrunk by approximately half during the past 100 years.

Most surprising aspect about glaciers is that they are advancing in Sweden and Norway. A shift in the jet stream has increased precipitation there enough to offset temperature rises. The Antarctic ice sheet is likely to gain mass because increase in precipitation there will surpass temperature increases. Greenland ice sheet is thickening at the rate equivalent to a fall in sea level of about 0.45 millimetres per year.

Nature, a scientific journal published from England, recently published a study that found the Antarctic has actually been cooling since 1966. Another study in Science, a journal published from USA, recently found the West Antarctic Ice Sheet has been thickening rather than thinning. Although, the Antarctic Peninsula has warmed over the past 50 years, it is a tiny part of the whole Antarctic continent.

Unless one is willing to believe the peninsula is responding to global warming while ignoring regional cooling, it becomes very difficult to link the ice shelf collapse to global warming. The authors analysed long­standing temperature data recorded throughout the continent, weighing all areas equally, rather than giving undue weight to the temperatures on the isolated peninsula, as had been done in the past.

Just how much, and just how rapidly, has Antarctica been cooling? The study found that temperatures across the continent have dropped an average of 0.125°F per year, or 1.2°F per decade, since 1978. This finding contradicts the findings of the climate models upon which the case for global warming is built. Those models predict the earth’s poles will warm more rapidly than the rest of the earth.

According to the study, “climate models generally predict amplified warming in the Polar Regions, as observed in Antarctica’s peninsula region over the second half of the 20th century.”

The study finds, “our spatial analysis of Antarctic meteorological data demonstrates a net cooling on the Antarctic continent between 1966 and 2000, particularly during summer and autumn.” The McMurdo Dry Valleys, for example, have cooled about 0.7°C per decade during this period of time.

The study noted a cascade of ecological problems triggered by the pronounced cooling. The number of small organic soil organisms is falling by 10 percent every year. Biological productivity in ice-covered freshwater lakes is declining at 9 percent each year. “The decline is alarming,” said study coauthor Diana Wall of Colorado State University. “These cooling repercussions may have a long-term effect. There is very little diversity here and the life cycle of these invertebrates is very slow.”

Just three days after the Nature study was released, Science magazine published results of a study concluding that the West Antarctic Ice Sheet has not only stopped melting, but is growing again. Using precise satellite measurements, a team of California Institute of Technology scientists working at the NASA Jet Propulsion Laboratory found “strong evidence of ice-sheet growth.”

The ice-sheet has been steadily melting since the end of the last ice-age roughly 10,000 years ago. Although very little of the overall melting has occurred since the dawn of the industrial age, a flurry of news reports in recent years has speculated that human-induced global warming will cause the thinning ice-sheet to break off from the Antarctic continent and inundate the world’s shorelines with a drastic rise in sea levels.

The thickening represents a reversal of the ice sheet’s long standing retreat, say researchers Ian Joughin and Slawek Tulaczyk, who authored the study. The thickening also throws cold water on the findings of British researchers, that the ice-sheet has a 5 percent chance of breaking off in the next 200 years.

This confusing, contradictory behaviour also shows up in the geological record. How these conflicting signals are to be understood? Unfortunately, this is a complex area in which detailed information is lacking. It is essential to understand the climate of glaciers before predicting about our future.