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Ice Odyssey

February 2004

Antarctica: the geography behind a record breaking trek

Ice Odyssey

This report looks at the geograhy behind the Tetley South Pole Mission which saw veteran polar explorer Pen Hadow and British businessman Simon Murray both walk into the history books.

  • What is wilderness?
  • What is the ‘economy and ecology’ in Antarctica?
  • ‘Ice erodes, deposits… and protects’- Antarctica’s glaciers
  • Antarctica under threat?
  • What are the new activites in Antarctica and the Southern Ocean?
  • What are the features of Antarctic ice?


What is wilderness?

Wilderness areas are remote and inhospitable areas of the world. They are increasingly subject to pressures from people and the global economy. It has special status, following the 1959 Antarctic Treaty to which 45 nations are now signatories. Earth’s fifth largest continent has been designated as a natural reserve devoted to peace and science. Nobody owns Antarctica, although 18 nations currently operate permanent station there (seven of whom had previously made a formal territorial claim). It is also an unusual wilderness region as it lacks any indigenous people.

Many of the world’s wilderness areas are under increased pressure as a result of what the geographer Janelle (1968) called ‘time-space convergence’. Modern transport now gives easy access to previously inaccessible areas. In this ‘shrinking world,’ wilderness regions are opened up to the flows of globalisation. Tourists and venture capitalists all begin to pay attention to regions such as Antarctica, as distance is ‘eradicated’ by transport and communications technologies such as air travel and the Internet.

As natural resources elsewhere are exhausted, might pressure mount to begin to exploit mineral deposits that may lie beneath the Antarctic wilderness? However, contrary to media hype, there are no known economic mineral resources in Antarctica. Geologists have discovered mineral occurrences and assessment of their economic potential is controversial.

Mineral resource activity (other than scientific research) is banned in Antarctica under the Environmental Protocol (1991). The Protocol has a mechanism to review the ban after 50 years, or before, if all Treaty nations agree.


What is the 'economy and ecology' in Antarctica?

Following the growth of the environment movement in the late Twentieth Century, there is great public support for the concept of wilderness. Nature photographers such as Ansel Adams and publications such as National Geographic magazine have done much to foster an appreciation of unspoilt nature. Recently, this appreciation of unspoilt nature has been harnessed as an economic resource through the concept of ecotourism (a model of tourism where an unspoilt natural environment becomes the principal attraction for visitors). As a result, Antarctica is getting increasingly busy. The table below shows that tourist numbers have increased by 100% over the last decade.

Year

Estimated number of tourists to Antarctica

1992-93

6704

1993-94

8016

1994-95

8120

1995-96

9367

1996-97

7413

1997-98

9604

1998-99

10013

1999-00

13826

2000-01

12248

2001-02

11588

2002-03

13571

Source:

IAATO

Some tourists merely gaze at the coast from icebreaking ships, while others enjoy a quick dip in the geo-thermally heated sea water on Deception Island. The more active engage in outdoor pursuits such as mountaineering, and for $45,000 it is even possible to take a guided ski trek to the South Pole. In addition to the 13,500 or so visitors that come to the ice each year, a further 3,000 take a 14-hour round-trip scenic air flight from Australia. The British Antarctic Survey has opened a gift shop in Port Lockroy (west coast) that receives 7,000 visitors each year. Port Lockroy is an old British research base, which was built during a top-secret WWII operation in 1944. It is now designated as a Historic Site under the Antarctic Treaty and operated by the British Antarctic Survey, with the guidance of the UK Antarctic Heritage Trust, as a "living museum". The operation and maintenance of the base is self-financing from the proceeds of this small gift shop at the base, with any surplus being used to help conserve other historic British bases in Antarctica.

This is all a far cry from 1899 when the very first Norwegian explorers set foot on the continent, having discovered its existence eighty years earlier. Following the pioneering expeditions of Amundsen, Scott and Shackleton, there has been permanent settlement for research purposes on Antarctica since the 1940s. However, this extraordinary growth in ecotourism is a far more recent phenomenon, with the first cruise ship entering Antarctic waters in 1967. The increased availability of Russian science vessels following the end of the Cold War has contributed to the upward trend in numbers. These are now leased to western tour operators, who can charge up to £10,000 for an Antarctic excursion.

Other economic activities are now largely restricted. Whaling in the Antarctic waters is one form of activity that survives but only at a very restricted level following the banning of commercial whaling in Antarctic waters in 1987. Excesses of previous generations – whalers drove four species close to extinction in the early 1900s – have now been curbed. Japan still kills 400 minke whales each year, allegedly for scientific purposes although the meat is sold. However, all Antarctic seals are now protected under international agreements.

Along with eco-tourism, the other major economic activity taking place in Antarctica is fishing. For a good summary of the fishing industry and the problem of incidental bird mortality on long-line hooks see the Birdlife International "Save the Albatross" campaign.


'Ice erodes, deposits...and protects'?

Antarctica contains the greatest volumes of ice found anywhere in the world. 99% of the continent is covered with ice. The area covered by sea ice varies with the seasons from around 3 million square kilometres at the end of the summer to around 20 million square kilometres at the end of the winter. However, this does not necessarily mean that the highest rates of mechanical weathering and glacial activity are always to be found here. It is a well-established fact, for instance, that freeze-thaw processes of frost wedging and inter-pore ice crystal growth only operate effectively when there are frequent cycles of melting and freezing of groundwater. New stresses are placed upon materials each time the water freezes and expands (by as much as 9%). The more freeze-thaw cycles that occur, the greater the overall intensity of weathering. When temperatures are permanently below zero, then rock is effectively locked in and weathering rates remain low overall. In Antarctica, mean monthly temperatures (MMT) are well below zero for almost all of the year. At the northerly maritime station of Rothera (UK), the mean monthly temperature is below zero for 10 months of the year, reaching a low of -11.6 degrees C in July.

Protecting rocks

A similar rule applies to the glacial erosion processes of abrasion and plucking. Sometimes, the high pressures exerted at the base of glaciers can lead to pressure melting, ice movement and erosion. However, in Antarctica, basal temperatures are so low that they more than compensate for the effect of this pressure. In addition, the intensity of the erosional process of abrasion is determined by the thickness of an ice mass. Beyond a certain depth, englacial and subglacial debris that might serve as abrasional material become locked firmly against the bedrock under the extreme pressure exerted by the overlying ice. This may prevent movement of the ice by basal sliding, even in glaciers that are only several hundred metres deep.

Near the heart of Antarctica, depths can exceed 15,600 feet (around 5 kilometres!). This suggests that large-scale basal sliding and subglacial erosion are probably very limited in many areas. Boreholes drilled in some parts of the continent have confirmed that ice basal temperatures are well below freezing point. In these areas, rates of sliding and abrasion will be very low. As a result, the underlying rocks are highly protected, remaining chemically and physically largely unaltered since the Antarctic land mass first broke away from the continent of Gondwanaland some 250 million years ago. The protection that low temperatures and the ice mass give to these rocks (and the fossils they frequently hold) makes them a valuable resource for geologists.

Protecting lakes

However, conditions beneath such deep ice cover are not easily observed and scientific opinion is divided over whether or not basal movement is actually taking place in many parts of Antarctica. Geothermal heat certainly keeps water above freezing point in some places deep below the ice surface (there is plentiful evidence of tectonic activity to be found throughout Antarctica, such as the lava lake at Mount Erebus) while heat is also generated by internal ice deformation processes. As a result of localised heating, there are now known to be at least 77 sub-glacial lakes beneath the Antarctic ice sheet, including one giant body of water located in 1996 near the old Russian base of Vostok. Lake Vostok is buried beneath 4 kilometres of the East Antarctic ice sheet. Scientists think that Lake Vostok was formed due to a combination of the intense pressure of the ice sheet above lowering the melting point of its basal ice, and geothermal heating from the bedrock below, possibly enhanced by hot water vents.

Organisms possibly living in this sub-glacial lake might prove to be a biological ‘time capsule’ and there has been much scientific debate over whether it should be tapped for analysis via a borehole or left undisturbed, protected by the great depth of ice lying above it.


Protecting and preserving air

Antarctic ice ‘protects’ in other useful ways. The ice protects and stores air from past millennia that can be sampled and analysed to give clues of climate change. When fresh snow falls, most of the air is squeezed out of the compacted underlying layers (to produce a form of ice known as firn). However, some air remains trapped within the firn, even in its densest form. Ice cores are thus extracted from glaciers and taken back to laboratories where they are melted under controlled conditions, freeing this trapped air. A recent two-mile deep ice core yielded 420,000 year-old air for analysis. Such evidence has shown scientists that carbon dioxide concentration in the atmosphere has risen sharply from 280 parts per million (ppm) in 1750 (the start of the industrial revolution) to 370ppm today.

Not so well-protected: Halley heads sea-wards again!

Halley station is located on the Brunt Ice Shelf. Here the ice sheet has flowed into an ice shelf, and rather than resting on a rock bed below sea level the ice is floating. Being afloat, the ice shelf experiences no friction so it moves much more rapidly than the ice sheet, currently at about 400 metres a year. Eventually, the front of the ice shelf will break away as a series of icebergs. Halley will have to be demolished and removed before this takes place and the base will have to be rebuilt for the sixth time since 1956.


How is Antarctica under threat?

Scientists are not sure what is causing the warming in the Antarctic Peninsula region. It is possible the climate in this region is subject to natural cycles or that the warming could be related to global climate change. The BAS has recorded that warming in the region has caused a rise of mean annual temperature of about 3 degrees C over the past 50 years, and the annual melt season has increased by two or three weeks over the last 20 years. So far, there is no evidence that the warming is "drastically modifying the marine food web".


Physical changes are evident. In March 2000, the world’s biggest iceberg, B15, broke away from the Ross Ice Shelf in Antarctica. 200 feet high and the size of Jamaica, it split in half in October 2003 (The Guardian, 15 November 2003) and is now beginning to waste further. Scientists believe this is a result of global warming and is linked to recent reports that glaciers in neighbouring Chile and Argentina are melting at twice the rate observed in the 1970s (The Guardian, 18 October 2003). Given that 70% of the earth’s fresh water is stored as ice in Antarctica, there is a clear threat of global eustatic sea level rises should Antarctica’s ice mass begin to decline further.

The Antarctic ozone hole was discovered by BAS scientists working at Halley station in 1985. CFCs were released in the primarily in the northern hemisphere and then transported to the southern hemisphere by global atmospheric circulation. The ozone hole forms over Antarctica because of the unique climatic conditions that prevail there. Ozone absorbs harmful ultraviolet radiation from the sun’s rays. As levels fall, the risk of sunburn, skin cancer and eye cataracts grows. People working in Antarctica are much more likely to get sunburnt and must take precautions by covering exposed skin or by applying sun block. Although global emissions have been greatly reduced, CFC molecules already released have a lifespan of 100 years.


What are the new activities in Antarctic and Southern Ocean?

 Some relatively new activities in Antarctica and the Southern Ocean are:

Longline fishing
Longline fishing
was once touted as an "environmentally friendly" technique compared with the immensely long "wall of death" drift nets and bottom trawls that destroy the sea floor. However longlines not only catch fish but an array of non-target species, including birds, turtles and sharks. There is international concern that the death rate of albatrosses and other seabirds arising from longline fishing is unacceptably high. Although the mortality arising from the legalised longline fishery is very low, there is much illegal, unregulated and unreported fishing. These activities were thought to account for the deaths of several tens of thousands of birds over the Southern Ocean as a whole.

Tourism
Tourism is a concern to the continent owing to the potential negative impact that mass tourism could have if not carefully controlled. Visitor numbers have more than doubled in the last 10 years but the International Association of Antarctica Tour Operators (IAATO) say that this growth of tourist numbers is relatively gradual. A Scott Polar Research Institute study suggests that despite the growth in visitors there is little evidence of a significant detrimental impact on the continent.

Bioprospecting
According to the United Nations, an increasing amount of the scientific research on the flora and fauna of Antarctica is underway with a view to identifying commercially useful genetic and biochemical resources. This type of research is likely to increase and ‘hunting’ these ‘extremophiles’ for research is often called bioprospecting. Bioprospectors’ interest in Antarctica stems from two reasons:

  • the lack of knowledge surrounding Antarctic biota provides an opportunity to discover novel organisms of potential use to biotechnology.
  • Antarctica’s environmental extremes, such as cold temperatures and extreme aridity and salinity, present conditions in which biota have evolved unique characteristics for survival.

Amongst the many examples of commercially useful compounds discovered, is a glycoprotein, which functions as the ‘antifreeze’ that circulates in some Antarctic fish, preventing them from freezing in their sub–zero environments. The application of this glycoprotein in a range of processes is being considered, including increasing the freeze tolerance of commercial plants, improving farm–fish production in cold climates, extending the shelf life of frozen food, improving surgery involving the freezing of tissues, and enhancing the preservation of tissues to be transplanted. Conclusions about the physical impact that bioprospecting has had on the biodiversity of Antarctica are not possible at this stage and it is not possible to ascertain if there has been a rise in collecting biodiversity components and whether the activity has resulted in damage to the Antarctic environment. It can be said, however, that interest by private sector firms in further research into commercially useful genetic resources and biochemical processes in Antarctica is on the increase. Although Antarctica is protected by the Antarctic Treaty, banning mining and other activities, the use of the continent for scientific research is well-established. However, such research is intended to be for the benefit of all - not for biotechnology companies who would keep the ‘patents' to themselves to make profits. The UN is warning that questions need to be asked now, before it is too late.


What are the features of Antarctic ice?

Ice sheets

The Antarctic ice sheet is the largest single mass of ice on Earth. It covers an area of almost 14 million km 2 and contains 30 million km 3 of ice. Around 90 per cent of the fresh water on the Earth's surface is held in the ice sheet, an amount equivalent to 70 m of water in the world's oceans. In East Antarctica the ice sheet rests on a major land mass, but in West Antarctica the bed is in places more than 2500 m below sea level. It would be seabed if the ice sheet were not there.

Even in summer Antarctic temperatures are below 0°C and so frost and snow crystals that gather on the surface of the ice sheet do not melt but accumulate year-by-year. As these crystals are buried the weight of the crystals above presses them together. Eventually, they are transformed into dense and impermeable glacial ice .

Glacial ice seems solid but under the tremendous pressures it experiences in the ice sheet, it will flow like a viscous liquid. This means that the ice sheet does not continue to get thicker as new snow falls but, under the action of gravity, flows over and around obstacles toward the sea. The ice sheet acts like a conveyor belt, taking ice from the atmosphere and delivering it back to the sea. Whether the mass of ice entering balances the amount leaving is the subject of considerable research.

Although the surface is cold, the base of the ice sheet is generally warmer, in places it melts and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet - these are ice streams.

Is climate change altering the ice sheet?

Glaciologists study the ice sheet using a variety of modern techniques, e.g., ice-penetrating radar, satellite sensing and field surveying. They measure ice thickness, the rate of accumulation and loss, and they image flow structures within the ice.

There is little evidence to suggest that the majority of the Antarctic ice sheet has altered significantly in the last 150 years but there is evidence that local changes are underway. Sea ice extent appears to be decreasing, and some ice shelves are breaking up. The most spectacular of these attracted considerable publicity, particularly the collapse of part of Larsen Ice Shelf in 1995.

Ice streams

Although they account for only 10 per cent of the volume of the ice sheet, ice streams are sizeable features, up to 50 km wide, 2000 m thick and hundreds of km long. Some flow at speeds of over 1000 m per year and most of the ice leaving the ice sheet passes though them.

Ice streams generally form where water is present, but other factors also control their velocity, in particular whether the ice stream rests on hard rock or soft, deformable sediments. At the edges of ice streams deformation causes ice to recrystallise making it softer and concentrating the deformation into narrow bands or shear margins . Crevasses , cracks in the ice, result from rapid deformation and are common in shear margins.

Ice shelves

Ice is less dense than water and because near the coast ice sheets generally rest on a bed below sea level, there comes a point where it begins to float. It floats in hydrostatic equilibrium and either it stays attached to the ice sheet as an ice shelf , or breaks away as an iceberg . Being afloat, ice shelves experience no friction under them, so they tend to flow even more rapidly than ice streams, up to 3 km per year. Much of Antarctica is fringed by ice shelves. Ross and Ronne-Filchner ice shelves each have areas greater than the British Isles.

Across the base of ice shelves, sea water and ice come into contact. Where this sea water is warm enough, the ice shelf will melt, adding cold fresh water to the sea. This diluted seawater eventually helps to form a water mass called Antarctic Bottom Water which is present in many of the deepest parts of the ocean.

Eventually ice breaks off the ice shelves to form icebergs. We will see shortly that ice shelves may be sensitive indicators of climate change.

Sea ice

Beyond the ice shelves is the sea. When the sea freezes it forms a salty type of ice, sea ice . The area covered by sea ice varies with the seasons, around 3 million km 2 in February, around 20 million km 2 in October.

Although only a few metres thick sea ice insulates the sea and limits the amount of sunlight reaching it. Lack of light limits growth of phytoplankton in the sea, though algae do multiply in the sea ice itself, sometimes turning it brown. The insulation effect reduces heat transfer between ocean and atmosphere, keeping the air cold and dry. Finally, as sea ice melts it cools both ocean and atmosphere. Because it limits energy transfer, the extent of sea ice is critical to the climate of the Southern Ocean.


Teachers’ Notes

Themes / Geographical relevance: Antarctica / exploration / glaciation / wilderness environments / climate change

14-16 activities 

1. Working in groups, plan a tourism package for Antarctica. You should consider the following as part of your plan:

  • What kind of people might be attracted to Antarctica?
  • How would they get there, travelling from Europe or America?
  • What kind of activities would be appropriate?
  • How much should tourists pay?
  • Who, if anyone, should profit from this kind of eco-tourism? And what should the money be used for?

2. Working in teams, prepare some arguments either in favour of, or against, the economic exploitation of Antarctic resources.

3. What other ‘wilderness’ environments can you think of?

AS/A2 exam tips 

Students of glaciation (a compulsory or optional topic for all boards except Edexcel specification B) need to have some knowledge of actual glacial environments. In particular, examiners will be impressed if you can show understanding of the diversity of glaciers and glacial processes that exists. The distinction between highly erosive temperate (Alpine) glaciers and far less erosive cold (Polar) glaciers needs to be drawn out. Details of ‘protective’ Antarctic glaciers can certainly be used to support any answer. With this in mind, try to draft a plan for the following essay question:

‘Glaciers erode, deposit and protect.’ Discuss


Wilderness environments are a feature of synoptic papers for both Edexcel Syllabus A and B. For instance, the specification for Syllabus B requires that students can answer the following questions:

  • What are wilderness areas? What are their characteristics?
  • What is the significance of wilderness regions?
  • Are such areas worth protecting?
  • How and why are pressures on such areas increasing?
  • How and why might protection constrain or conflict with economic development?

Try to draft answers to these questions using the material included in this article.

This report was written by Dr Simon Oakes who works for the Flood Hazard Research Centre (Middlesex University) and Mander Portman Woodward School (London). He is a senior examiner for Edexcel. It was edited by Dr John Shears, Head of the Environmental Office with the British Antarctic Survey (BAS) and senior author of the Antarctic Schools Pack.

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