Glacial ice is a climatic archive, while glaciers are often referenced as memoirs of the history of climate. Hence, the spectacular global retreat of mountain glaciers is still the most definitive evidence of a striking change in our planet’s climate since the end of the minor ice age in the mid-nineteenth century. That is why mountain glaciers are considered key indicators of climate changes, somewhat like global thermometers. 1)
Melting of glaciers has been especially well-documented in the Alps. The findings show that Alpine glaciers have on average lost about a third of their surface area and half their volume – just between the mid-nineteenth century and the mid-1970s. Another 20 to 30% of the ice has melted since. Estimates are that the loss in the hot summer of 2003 alone amounted to about 5 to 10% of the total glacial volume. 2)
The magnitude of this shrinkage has already reached the stage projected for the year 2025. Glacier researchers anticipate that Alpine glaciers will disappear totally within this century. 3)
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Melting of glaciers is a global issue. Investigations by the World Glacier Monitoring Service indicate that since 1980, reference glaciers in the mass balance network have lost about 30 cm of ice depth in their middle per year. And the melt rate is accelerating!
The World Watch Institute predicts that about a quarter of the glacial mass will be gone by the year 2050. Almost all glaciers are melting rapidly in the high mountain ranges around the globe – in Europe, North & South America, Africa, and Asia.
About 2.000 of the Eastern Himalayan glaciers have disappeared.
Kilimanjaro is the highest African mountain with a peak of 5.895 meters. Since the earliest records dating back to 1912, it has lost about 80% of its mass of snow and ice. Each year, about another half meter of ice melts. Ice samples taken by researchers suggest that the glacier is about 11.700 years old. The last bit of glacial ice on this mountain could disappear in less than two decades.
Once the ice is irretrievably lost, we also lose our planet’s climate archive.
Shrinking of glaciers is also alarming in Patagonia. Greenpeace claims that over 40 cubic kilometers (roughly 10 cubic miles) of the ice here melts each year. The Patagonian ice fields of Chile and Argentina are among the fastest melting masses of ice on earth.
The potential dangers worsen around the world with the melting of glaciers:
The 4th IPCC Report dated February 2007 issued a warning of ocean levels rising at an accelerating rate. Between the years 1961 and 1992, the sea level rose by about 1.8 millimeters annually. From 1993 through 2003, this had increased to 3.1 millimeters per year.
In 2002, UNEP, the United Nations Environmental Program, published a study that warned of flood disasters caused by melting of glaciers in the Himalayas. Valleys and major drainage zones face real dangers posed by very high water levels in 44 glacial lakes. The rapidly rising levels of these lakes, presently impounded by ice dams, rubble, and detritus, could turn into major floods waters following a dam breach. The Andes face similar dangers. We lack regular monitoring and early warning systems. After floods, we face the threat of drought and desertification. Glaciers feed Asia’s major rivers.
Computations suggest that if all of Greenland’s ice cover melted, levels of oceans around the world would rise by at least seven meters.
It is frightening to see the rate at which the polar caps are losing their ice. The melt rates of glaciers and Arctic ice are even higher than was predicted a few years back. Temperatures at the polar caps have risen two to three times more than the global average.
The Arctic Ocean may be ice-free in just 50 to 70 years.
The Western Arctic has seen huge chunks of ice break off and drift as icebergs into the Antarctic Ocean, or form gigantic barriers to the open sea.
The unique ecological systems of the polar regions are in acute danger.
Climate change is endangering the survival of polar bears in the northern polar region, and that of penguins at the South Pole.
Polar caps and their glaciation are critical for the global climate. No one is venturing to even predict what the dwindling of glaciers in these icy regions could mean for our global climate.
In their fourth and latest report released on February 2., 2007, scientists from IPCC, the Intergovernmental Panel on Climate Change of the United Nations, warned of global warming by up to 6.4 °C by the end of the century. Depending on the rise in greenhouse gases, the best case scenario predicts a global temperature increase of 1.1 to 2.9 °C, with a worst case scenario predicting between a 2.4 and 6.4 °C rise. Eleven of the last twelve years were among the warmest since the beginning of weather data recording in the mid-nineteenth century. Recent years are clear signals: 2001 and 2002 were unusually warm, while the summer of 2003 in Europe broke all heat records. Scientists at NASA’s Goddard Institute for Space Research reported that in 2006 our planet reached its global warming peak since the last 12.000 years. According to NASA, 2005 was the hottest year on record, and 2006 broke many weather records – such as snowfalls early in the year, the heat in July, a hot fall, and a snow-free winter. The mean global temperature rose by about 0.8 °C over the past century, of which a 0.6 °C rise occurred in the last three decades.
Continents in the middle to upper latitudes of the northern hemisphere have warmed up the most so far. Within the 20th century, the temperature in Germany has risen by 0.9 °C, by 1.1 °C in Austria, and by 1.4 °C in Switzerland. Especially the Alps heated up even more – by up to 2 °C.
The main cause is higher CO2 levels from the use and burning of fossil fuels like oil, coal, and natural gas.
This process will accelerate in coming years. It takes about three decades for the impact of CO2 emissions to set in. What we are seeing today is the effect of CO2 emissions from three decades ago. That means that we are presently orchestrating the climate change for the next three decades.
Mountain ranges experience more extreme climate changes, just like the polar caps. The Alps have already warmed up by as much as 2 °C. Higher elevations are seeing a more rapid rise, whereas minimum temperatures are increasing at triple the rate of the maximums. This means that nights will get warmer 4). The years 1994, 2000, 2002, and 2003 were the warmest ones in the Alps since five centuries.
In the summer of 2003, for weeks the freezing point elevation lay over the 4.000 m mark. And this has repeated itself.
The regional distribution of climatic factors can vary. These include the solar radiation intensity and distribution pattern over time, a drop in the albedo, water evaporation, humidity, the intensity and distribution over time of rain and snow quantities, temperatures, atmospheric pressures, and air movements.
It appears that climate warming in the Alps will continue at a rate faster than the average. 5)
The dwindling volume and loss of glacial mass results not only from less snow in winter, but primarily from very sunny and warm spring and summer months combined with heavy rains. This is quite evident from measurements of selected glaciers in Switzerland and Austria. 6) 7) Besides climate change, the melting of glaciers is also intensified by air pollution and the depositing of dirt directly in glacial ski resorts – particularly fine particles and soot. Even sand from the Sahara is collecting on the glaciers.
A white surface on the ice reflects back almost all the sunshine. However, the darker the glacier’s ice surface becomes from deposits of dirt, the lower the albedo. The result – ice absorbs more heat from the sun.
Other conditions are also changing. A weakening ozone layer leads to greater high-energy, short-wave UV radiation. On top of this, waste gases, fossils, and other combustion processes cause changes in chemical reactions in the air and lead to precipitation, like acid rain.
Analyses of fish have shown that high-elevation lakes, like the Tyrolean Schwarzsee, are contaminated with long-life toxins. These will take much longer to break-down here than in waters at lower elevations. 8)
Glaciers are not just a climate archive. They also store our industrial pollution, which is released as the glaciers melt.