GEOG101 Study Guide

Unit 13: The Pacific and Antarctica

 13a. Compare and contrast the regions of Melanesia, Micronesia, and Polynesia

  • What factors are used to distinguish between the regions of Melanesia, Micronesia, and Polynesia?
  • Describe the relative geographic locations of Melanesia, Micronesia, and Polynesia.
  • How do the prefixes mela-, micro-, and poly- describe their respective regions?
  • Why are the Pacific islands considered an extreme peripheral realm?

The islands of the Pacific are divided into three regions according to their physical geography, the local inhabitants, and location.

  • The region of Melanesia was originally named for the dark skin color of the inhabitants; melano is Greek for black. These islands are immediately north of Australia and east of Indonesia.
  • Micronesia, or small islands, is named for the size of its more than 2,000 individual islands. This region borders Melanesia to the north and is east of the Philippines and Taiwan.
  • Polynesia, or many islands, is named for its vast number of islands and archipelagos. It forms a large triangle that borders Micronesia and Melanesia to the east, extending from Hawaii in the north, New Zealand in the south, and Easter Island in the east.

All three regions are considered an extreme peripheral realm because their natural resources have not, historically, been vital to any core areas.

Review The Pacific Islands.

 

13b. Distinguish between low islands and high islands

  • What are high and low islands?
  • How are low islands related to high islands?
  • Which regions are dominated by high or low islands?

The distinction between high and low islands is based on their origin rather than their elevation. High islands are of volcanic origin, and low islands are formed from the sedimentation or uplift of coral reefs. Some low islands are hundreds of feet in elevation, such as Nauru in Micronesia which reaches 233 feet above sea level. There are also high islands that rise only a few hundred feet above sea level.

High and low islands are often found in proximity to each other because low islands often surround submerged extinct volcanoes as atolls. These once high islands have eroded to the point that they have subsided, leaving only a ring of growing coral visible at the surface. Most of Micronesia is composed of low islands, whereas Polynesia and Melanesia have many high islands. All three regions intersect the Pacific Ring of Fire. 

Review The Pacific Islands.

 

13c. Describe the primary economic activities of the islands in the Pacific

  • Long self-sufficient, why must many Pacific Islands now rely on core regions for economic support?
  • How has globalization affected the islands of the Pacific?
  • Explain why tourism is important to the economies of the Pacific Islands.

Fishing has long supported the economies of the Pacific Islands but, recently, overfishing has made that impossible. An increase in population has exacerbated the problem of low fish stocks. Thus, to feed its population and gain national wealth, the Pacific Islands are increasingly dependent on core regions. Tourists from these core regions are a major source of revenue. Although some islands have a few natural resources, such as the phosphates mined on the Micronesian island of Nauru, most are dependent on the attractiveness of their climate and beaches.

A number of islands and archipelagos are under the jurisdiction of the United States, France, the United Kingdom, or New Zealand. Thus, western culture has significantly influenced the traditional cultures of Guam, the Northern Marianas Islands, Wake Island, American Samoa, the Hawaiian Islands, New Caledonia, French Polynesia, Pitcairn Islands, and Cook Islands. Furthermore, modern technology has made globalization inevitable even among the independent countries of the Pacific Island realm. Although still relatively remote, the islands of the Pacific are not as isolated as they once were.

Review The Pacific Islands.

 

13d. Summarize the main environmental concerns of the islands in each region of the Pacific

  • What impact did World War II and the Cold War have on the environmental conditions of some of these islands?
  • What are the natural hazards that threaten many of these islands?
  • Why is freshwater in short supply on many islands?
  • How is climate change expected to affect the Pacific Islands?

A variety of environmental issues challenge the regions of the Pacific Islands.

  • Troops from Japan, the United States, and New Zealand all used islands in the Pacific during World War II. Guam, Hawaii, Fiji, and New Caledonia were particularly affected by deforestation, ordnance dumping, and the introduction of invasive species, among other forms of environmental damage.
  • Following World War II, several countries used islands in the Pacific for nuclear testing during the Cold War. The United States, for example, detonated nuclear weapons in eastern Micronesia on the Bikini Atoll, which is part of the Marshall Islands. Radioactive fallout remains a concern there and other areas where the United Kingdom and France tested nuclear weapons.
  • Because many of the Pacific islands are part of the Ring of Fire, they are vulnerable to volcanic eruptions, earthquakes, and tsunami waves. Their remote locations also make evacuation efforts more complicated.
  • Surrounded by salt water, the islands of the Pacific must rely on rainfall to replenish their freshwater resources. The population on many of these islands, however, is increasing and, therefore, straining freshwater supplies.

In addition to these challenges, sea level rise due to climate change threatens the existence of some island countries. Kiribati's islands in Micronesia and Polynesia may, for example, be completely submerged. On other islands, sea level rise means the contamination of freshwater supplies and agricultural land and other hazards.

Review 

 

13e. Describe the physical geography of Antarctica

  • Explain how Antarctica can be a desert even though it is covered by ice.
  • What landform dominates Antarctica beneath its ice sheet?
  • What evidence is there for tectonic activity in Antarctica?

Antarctica is a desert because it receives so little precipitation annually. Because it is so cold there, what little snow falls rarely melts. Over time, the snow that does fall compresses the layers of snow below, forcing it to recrystallize into granules that become more dense as air space between the grains decreases. This process takes more than a hundred years. Although Antarctica began icing about 45.5 million years ago, scientists have, thus far, only been able to extract samples dating to 800,000 years ago.

Beneath Antarctica's ice sheet, the terrain is mountainous, with the highest average elevation of any continent in the world at 8,200 feet. The Transantarctic Mountains, one of the longest mountain ranges on Earth, bisects Antarctica. At higher than 14,800 feet above sea level, some of its peaks are ice-free. The Ellsworth Mountains to the west of the Transantarctic range include Mount Vinson, the highest point on the continent at 16,050 feet. There are also volcanoes under Antarctica's ice sheet. These volcanoes, including Mount Erebus, are likely due to the West Antarctic Rift System, which is where the Antarctic tectonic plate is thinning. This is similar to the tectonic activity occurring along the East African Rift. 

Review: 

 

13f. Discuss the political struggle of governing Antarctica and how the international community manages the continent

  • What countries claimed territory in Antarctica prior to 1959?
  • Explain what the Antarctic Treaty regulates.
  • Who lives in Antarctica?

Before 1959, seven countries claimed territory in Antarctica: Argentina, Australia, Chile, France, New Zealand, Norway, and the United Kingdom. Friction between several claimant countries led to negotiations that resulted in the Antarctic Treaty, which regulates international relations regarding Antarctica.

  • In addition to the seven claimants there were five more original signatories to the Antarctic Treaty: Belgium, Japan, South Africa, the United States, and the USSR.
  • There are now 54 signatories to the Antarctic Treaty. Countries wanting consultative status demonstrate their commitment to the continent by engaging in substantial research there.
  • The signatories have agreed to set the continent aside as a scientific preserve to be used for peaceful purposes only.
  • The Treaty bans military activity, resource extraction, and waste disposal.
  • The most recent action to increase the environmental protection of Antarctica was the Madrid Protocol in 1998.
  • One of the new key provisions of the Treaty is a requirement that all activities, including tourism, undergo an environmental assessment.

Antarctica does not have a native human population. There are staff research stations, with about 1,000 people there in the winter and about 5,000 in the summer.

Review the section on The Antarctic Treaty in Antarctica.

 

13g. Describe the effects of global warming

  • Define global warming.
  • What is the connection between global warming and climate change?
  • Why are the effects of global warming on Antarctica critical for the entire world?

Global warming is the long-term heating of Earth's climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities. Burning fossil fuels is the primary cause because it increases heat-trapping greenhouse gas levels in Earth's atmosphere. The effects of global warming include:

  • melting glaciers, polar ice sheets, and sea ice,
  • increasingly acidic oceans,
  • lower air quality,
  • and loss of habitat, among many other consequences.

Global warming is not the same as climate change; it is a component of it. Climate change includes both human- and naturally-produced warming. For example, emissions from volcanic eruptions and coal-burning utilities contribute to climate change but only the emissions from coal-burning utilities contribute to global warming.

As Earth's atmospheric temperature increases, Antarctica's ice pack decreases. In addition to the increase in global sea level as the Antarctic ice sheet melts, there is also an increase in global temperatures. Without white snow and ice to reflect the Sun's rays, the remaining darker surfaces will absorb solar radiation, further increasing the temperature of Earth's atmosphere. The higher temperatures will result in more extreme weather events.

Review the section on Climate Change in Antarctica.

 

13h. Explain the natural and human causes of climate change on Earth

  • How is climate change related to the Industrial Revolution?
  • What are some examples of natural causes of climate change?
  • What are greenhouse gases?

Earth's average surface temperature has been increasing since the late 19th century, coinciding with the increase in carbon dioxide emissions from the Industrial Revolution.

  • Coal and later petroleum and natural gas were the fuel sources that powered the new technologies of the Industrial Revolution, including the steam engine.
  • Burning coal and other fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere.
  • Greenhouse gases, including carbon dioxide, nitrous oxide, methane, water vapor, and chlorofluorocarbons, trap heat in the atmosphere, eventually raising Earth's surface temperature.
  • Although greenhouse gases, with the exception of chlorofluorocarbons, are naturally occurring, they have been released in far greater quantities than is natural since the beginning of the Industrial Revolution.

Natural processes also emit greenhouse gases and contribute to climate change in other ways. Volcanoes, for example, emit carbon dioxide. Changes in Earth's orbit, ocean currents, and solar intensity can also affect climate change.

Review the section on Climate Change in Antarctica.

 

13i. Describe how the amount of ozone in the stratosphere above the South Pole changes during the seasons

  • What role do polar stratospheric clouds play in seasonal ozone depletion?
  • Why does stratospheric ozone thin between September and December?

Stratospheric ozone levels over the South Pole vary seasonally due primarily to Earth's tilted axis of rotation and air circulation patterns. During the winter months, June to September, ozone levels increase and begin to decrease in the spring.

  • Polar stratospheric clouds, which form during the winter months, provide the conditions for ozone destruction by trapping chlorine and nitric acid.
  • When sunlight returns to the South Pole in the spring, it reacts with the trapped chemicals, destroying the ozone.
  • Thus, stratospheric ozone thins with the loss of cloud cover and the constant exposure of the South Pole to sunlight.

When stratospheric ozone thins, it is referred to as a hole in the ozone layer even though there is not a complete absence of ozone.

Review the section on Ozone Depletion in Antarctica.

 

13j. Explain how ozone in the stratosphere protects living organisms from incoming solar ultraviolet (UV) radiation

  • Why is ultraviolet radiation (UV) harmful?
  • What is the difference between tropospheric and stratospheric ozone?

As shown in the following figure, the sun emits ultraviolet radiation (UV), some of which is absorbed by the ozone in the stratosphere. UV radiation is beneficial because it promotes vitamin D production, but overexposure to it harms living organisms. Too much UV radiation causes skin cancer, premature aging, eye damage, immune system impairment, and reductions in phytoplankton productivity. When chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) destroy ozone, more UV radiation makes it to Earth's surface, accelerating harm to living organisms. Without the protection of stratospheric ozone, UV radiation would sterilize the Earth, making life impossible.


Ozone in the stratosphere protects life on Earth, but ozone in the troposphere, the lowest layer of the atmosphere, is harmful. Tropospheric ozone forms when hydrocarbons and nitrogen oxides released from automobile tailpipes and smokestacks react with sunlight. Thus, high levels of tropospheric ozone are often found in urban areas during the summer months. Breathing ground-level ozone can trigger a variety of health problems such as bronchitis, chest pain, and asthma, among others.

Review the section on Ozone Depletion in Antarctica.

 

Unit 13 Vocabulary

This vocabulary list includes terms that students need to know to successfully complete the final exam for the course.

  • Antarctic Treaty
  • archipelagos
  • chlorofluorocarbons (CFCs)
  • climate change
  • Cold War
  • consultative status
  • core regions 
  • deforestation 
  • desert 
  • East African Rift
  • Ellsworth Mountains
  • extreme peripheral realm
  • fishing 
  • fossil fuels
  • global warming
  • greenhouse gas
  • high islands
  • hydrocarbons
  • hydrochlorofluorocarbons (HCFCs)
  • Industrial Revolution
  • invasive species 
  • low islands
  • Madrid Protocol
  • Melanesia
  • Micronesia
  • Mount Erebus
  • Mount Vinson
  • nitrogen oxides
  • ordnance dumping
  • overfishing 
  • ozone
  • Pacific Ring of Fire
  • phosphates 
  • Polynesia
  • radioactive fallout 
  • remote 
  • scientific preserve
  • South Pole 
  • stratosphere 
  • stratospheric ozone
  • Transantarctic Mountains
  • troposphere
  • tourists 
  • ultraviolet radiation (UV)
  • West Antarctic Rift System
  • World War II