Year 9 Humanities: Vanishing Worlds Study Guide

Vanishing Environments: Definition and Global Overview

• A vanishing environment is defined as a natural area being damaged, degraded, or destroyed at a rate faster than it can naturally recover.

• These changes are typically driven by human activities, though natural processes also contribute to environmental shifts.

• Significant examples of extraordinary vanishing environments include:

  • The Amazon Rainforest in South America.

  • The Great Barrier Reef located off the coast of Australia.

  • The glaciers of the Himalayas in Asia.

  • The low-lying islands of the Maldives in the Indian Ocean.

• Why environments vanish: Changes occur through interconnected reasons. While natural processes have shaped the Earth over thousands of years, modern human actions have become the dominant cause, altering landscapes at a pace significantly faster than natural cycles.

• Critical global statistics regarding vanishing environments:

  • The world has lost one-third ($1/3$) of its total wetlands since the year $1970$.

  • Half ($50\,\%$) of the world's coral reefs are currently damaged or dying.

  • Arctic sea ice is shrinking by nearly $13\,\%$ per decade.

  • Glaciers are currently melting at the fastest rate recorded in the last $2,000$ years.

  • Humans destroy approximately $10\,\text{million}$ hectares of forest every year, an area equivalent in size to the country of Portugal.

Causes of Environmental Change: Natural vs. Human Impacts

• In the past, internal and external natural forces such as volcanic eruptions, changes in solar radiation, and shifts in ocean currents influenced the Earth's climate gradually.

• Modern scientific evidence indicates that current rapid global changes are primarily human-driven.

• Comparison of cause types:

  • Natural Causes: These are powerful but generally short-term and regional in impact. Examples include volcanic activity (ash can cool temperatures but also creates fertile land), floods and droughts (often part of cycles like El Ni\u00f1o and La Ni\u00f1a), and earthquakes or landslides that suddenly reshape local habitats.

  • Human Causes: These have a greater, longer-lasting, and global effect because they alter the atmosphere's composition. Key activities include deforestation ($1\,\text{billion}$ tonnes of $CO_2$ released annually by the Amazon alone), urbanisation (creating "urban heat islands"), pollution (industrial and agricultural runoff), and human-induced climate change from burning fossil fuels.

• Scientific Evidence for Human Impact:

  • The Intergovernmental Panel on Climate Change (IPCC) reports that more than $95\,\%$ of current global warming is caused by human activity.

  • Global $CO_2$ concentrations have increased from $280\,\text{ppm}$ in the year $1750$ to over $420\,\text{ppm}$ currently, levels not seen for at least $3\,\text{million}$ years.

  • The Earth's average surface temperature has increased by $1.2\,^\circ\text{C}$ since the late $1800s$.

  • The period from $2015$ to $2023$ represents the nine warmest years ever recorded.

  • Sea levels are currently rising at a rate of approximately $3\,\text{mm}$ per year.

The Science of the Greenhouse Effect

• The Earth's atmosphere functions like a blanket. Sunlight reaches the surface, is absorbed, and is then re-emitted as infrared radiation (heat).

• Greenhouse Gases (GHGs): Specific gases including carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$) trap this heat, maintaining the planet's warmth.

• Natural Greenhouse Effect vs. Enhanced Greenhouse Effect:

  • Without these gases, the Earth's average temperature would be approximately $-18\,^\circ\text{C}$ instead of the current average of $+15\,^\circ\text{C}$.

  • Since the Industrial Revolution, the burning of fossil fuels and forest clearing have increased GHG concentrations, trapping excess heat.

• Results of the Enhanced Greenhouse Effect:

  • Increasing global temperatures.

  • Melting of glaciers and polar ice.

  • Rising global sea levels.

  • Frequent and more extreme weather events.

Understanding Ecosystem Services and Interdependence

• Ecosystem services are the goods and benefits that humans gain from the natural world, serving as the foundation for health, food security, and global economies.

• Key Types of Ecosystem Services:

  • Provisioning Services: Physical resources such as food, water, timber, and raw materials. Forests provide roughly $50\,\%$ of global drinking water; coral reef fisheries feed over $500\,\text{million}$ people.

  • Regulating Services: Maintaining atmospheric and climate stability. Forests and peatlands act as carbon sinks, absorbing about $30\,\%$ of human $CO_2$ emissions each year. Wetlands filter pollutants and prevent floods, saving nations billions in damage costs.

  • Cultural Services: Enrichment through spiritual meaning, education, and tourism. The Great Barrier Reef generates approximately $A\$6\,\text{billion}$ for the Australian economy and attracts $2\,\text{million}$ visitors yearly.

• Interdependence: Living things and natural systems depend on one another. When one service fails, it causes a cascade effect. For instance, Amazon deforestation reduces regulating services (carbon storage), which accelerates climate change, subsequently threatening provisioning services (rainfall for agriculture).

• Global Importance: Nearly half of all ecosystem services are currently in decline. The World Bank warns that the loss of key natural systems could cost the global economy up to $US\$2.7\,\text{trillion}$ per year by the year $2030$.

The Tropical Rainforest Biome: Focus on the Amazon

• Location: Tropical rainforests are located between the Tropics of Cancer and Capricorn (roughly $23.5\,^\circ\text{N}$ to $23.5\,^\circ\text{S}$ of the Equator).

• Climate Characteristics of the Equatorial Climate:

  • Constant high temperatures (daily range of $25\text{--}30\,^\circ\text{C}$).

  • High annual rainfall ($2000\text{--}3000\,\text{mm}$).

  • High humidity ($80\text{--}90\,\%$).

  • Little to no seasonal variation in day length or temperature.

• Biodiversity Snapshot: Rainforests cover less than $6\,\%$ of the Earth's land surface but house over $50\,\%$ of all known species.

  • The Amazon is home to more than $16,000$ tree species and $2.5\,\text{million}$ insect species.

  • The Congo Basin provides habitat for the mountain gorilla and forest elephant.

  • Borneo is the exclusive home of the orangutan.

• The Amazon Rainforest Specifics:

  • Covers over $5.5\,\text{million}\,\text{km}^2$ across nine countries.

  • Known as the "lungs of the planet," it produces roughly $20\,\%$ of the world's oxygen and stores $100\,\text{billion}$ tonnes of carbon.

  • Tipping Point: Since $1970$, $17\,\%$ of the forest has been cleared. Scientists warn that reaching $25\,\%$ deforestation could trigger a tipping point, turning the rainforest into dry savanna (savannisation).

Causes of Amazon Deforestation

• Cattle Ranching: The single largest cause in Brazil, accounting for approximately $80\,\%$ of deforested land. Pastures are created to produce beef for export to the US, China, and Europe.

• Commercial Agriculture: Brazil is a leading exporter of soybeans for animal feed. Roughly $10\,\%$ of deforested land is used for commercial agriculture, with another $5\,\%$ for small-scale farming.

• Logging: High-value hardwoods like Mahogany and Ipe are harvested. An estimated $80\,\%$ of Amazon logging is illegal, and logging roads (over $100,000\,\text{km}$) facilitate further encroachment.

• Mining and Infrastructure: Accounts for around $2\,\%$ of deforestation. Mining for iron ore, gold, and bauxite contaminates rivers with mercury. Road building, like the Trans-Amazonian Highway, has increased forest access by over $400\,\%$ in the last $30\,\text{years}$.

• Economic Perspective: Governments often view the forest as a resource to drive growth and provide jobs, but short-term profits ($billions$ of dollars in exports) are offset by long-term environmental costs.

Impacts of Deforestation in the Amazon

• Environmental Impacts:

  • Soil Erosion: Tree roots bind soil. Without them, heavy rainfall causes leaching, making the land infertile within a few years. Erosion rates can be $50\,\text{times}$ higher in cleared areas.

  • Loss of Biodiversity: Approximately $137\,\text{species}$ are lost every day globally in tropical forests. Endangered species include the giant river otter and harpy eagle.

  • Carbon Release: The Amazon has transitioned from a carbon sink to a source, emitting about $1\,\text{billion}$ tonnes of $CO_2$ annually due to fires and clearing.

  • Water Cycle Disruption: Trees release moisture through transpiration. Reduced forest cover leads to less rainfall, threatening water supplies for major cities like S\u00e3o Paulo and Lima.

• Social and Economic Impacts:

  • Indigenous Displacement: Over $350$ Indigenous groups, including the Yanomami and Kayapo, face loss of culture, disease, and conflict as they are driven from ancestral lands.

  • Economic Collapse: After initial gains, soil exhaustion and reduced rainfall (up to $30\,\%$ less) lead to agricultural failure.

  • Data Snapshot: Cleared land can lose up to $80\,\%$ of its nutrients within only three years.

Strategies for Saving the Amazon Rainforest

• Protected Areas and Indigenous Reserves: Over $20\,\%$ of the Amazon is currently protected. Examples include Ja\u00fa National Park ($2.3\,\text{million}$ hectares) and Tumucumaque Mountains National Park ($3.9\,\text{million}$ hectares). Deforestation is $3\,\text{times}$ lower in Indigenous territories.

• Ecotourism: Provides income without destruction. Examples include the Tambopata Reserve in Peru and the Napo Wildlife Centre in Ecuador (owned by the Kichwa people).

• Debt-for-Nature Swaps: Wealthier nations reduce a country's debt in exchange for environmental investment. In $2010$, the US cancelled $US\$21\,\text{million}$ of Brazil's debt for rainforest protection.

• Reforestation and Education: Projects like "Reforest Amazonia" have planted over $3\,\text{million}$ native trees. Initiatives like the Zero Deforestation Cattle Agreement and agroforestry training for farmers help maintain economic viability sustainably.

Coral Reefs: Ecology and Global Distribution

• Biology: Reefs are built by coral polyps that secrete calcium carbonate skeletons. They have a symbiotic relationship with zooxanthellae (algae) which provide oxygen and food through photosynthesis.

• Distribution (The "WEST LDS" Conditions):

  • W (Wave action): Gentle movement for oxygen and nutrients.

  • E (Exposure): Must stay mostly underwater.

  • S (Sediment): Needs clear water free of silt.

  • T (Temperature): Optimal growth between $23\,^\circ\text{C}$ and $29\,^\circ\text{C}$.

  • L (Light): Shallow water (usually less than $60\,\text{m}$) for photosynthesis.

  • S (Salinity): Stable, salty ocean water.

• Major Reef Systems:

  • Great Barrier Reef (Australia): Over $2,300\,\text{km}$ long.

  • The Coral Triangle (Southeast Asia): Global center of marine biodiversity.

  • Caribbean Sea and Red Sea: Notable for high salinity and resilient species.

Threats and Impacts of Reef Loss

• Major Threats to the Great Barrier Reef (GBR):

  • Coral Bleaching: Heat stress (above $30\,^\circ\text{C}$) causes polyps to expel algae. Mass events occurred in $2016$, $2017$, and $2022$. Shallow-water coral cover fell from $50\,\%$ in $1985$ to $25\,\%$ in $2020$.

  • Ocean Acidification: Dissolved $CO_2$ forms carbonic acid. The ocean is $30\,\%$ more acidic (pH dropped from $8.2$ to $8.1$), slowing skeleton construction.

  • Pollution: Runoff from sugarcane and cattle farms (Burdekin and Fitzroy rivers) causes algal blooms.

• Impact of Reef Loss on Livelihoods:

  • Marine Food Web Collapse: Fish populations have dropped by over $50\,\%$ in parts of Fiji. Small fish (parrotfish, butterflyfish) lose shelter, impacting predators like reef sharks.

  • Coastal Vulnerability: Reefs absorb $97\,\%$ of wave energy. Loss increases flooding risks for Tuvalu and Kiribati.

  • Economic Loss: Tourism linked to reefs accounts for $40\,\%$ of Fiji's GDP. Global loss could cost the world over $US\$10\,\text{trillion}$ by the year $2100$.

  • Cultural Loss: Traditional fishing grounds (qoliqoli in Fiji) represent identity and heritage.

Case Study: Small Island Nations at Risk (Maldives and Kiribati)

• Physical Vulnerability: Nations like the Maldives, Kiribati, and Tuvalu sit only $1\text{--}3\,\text{m}$ above sea level. Sea level rises of $3\text{--}4\,\text{mm}$ per year could submerge them by $2100$.

• The Maldives Paradise in Peril:

  • Average land height is $1.5\,\text{m}$. $80\,\%$ of islands are less than $1\,\text{m}$ high.

  • Solutions: Hulhumal\u00e9, an artificial island built $2\,\text{m}$ above sea level. Thilafushi (landfill island) and "Floating Cities" designed for $20,000$ people.

  • Challenges: Saltwater intrusion makes $80\,\%$ of wells in northern atolls undrinkable. Capital Mal\u00e9 is protected by a $3\text{--}\text{metre}$ high concrete wall.

• Kiribati and "Migration with Dignity":

  • Consists of $33$ atolls; capital is South Tarawa. Sea level rises at $4\,\text{mm}$ per year.

  • Migration Strategy: The government bought $20\,\text{km}^2$ of land on Vanua Levu, Fiji, as a safe haven. The policy focuses on training citizens for skilled jobs abroad to ensure they migrate voluntarily rather than as refugees.

• Global Ethics: These nations contribute less than $0.0002\,\%$ of global carbon emissions but face total loss of sovereignty and culture.

Glaciers and Frozen Environments

• Definition: Glaciers are slow-moving masses of ice formed from compressed snow. As snow compresses, it becomes "firn" before turning into glacial ice.

• Types of Frozen Environments:

  • Alpine Glaciers: Found in mountain ranges (e.g., Fox and Franz Josef in New Zealand).

  • Ice Sheets: Continental masses (Greenland and Antarctica).

  • Sea Ice: Found in the Arctic.

• Global Importance and Albedo Effect:

  • Store $70\,\%$ of the world\u2019s freshwater.

  • Feed major rivers (Ganges, Yangtze) supporting billions.

  • Bright surfaces reflect solar radiation (the Albedo Effect); melting exposes dark land/water, which absorbs more heat (a positive feedback loop).

• Impacts of Melting Glaciers:

  • Environmental: Rising sea levels (Greenland adds $0.8\,\text{mm}$ annually), Glacial Lake Outburst Floods (GLOFs) in Nepal/Bhutan.

  • Human: Water insecurity for agriculture in India and Pakistan; decline in hydropower in the Andes; cultural loss for mountain communities.

  • New Zealand Case: The Franz Josef Glacier has retreated over $800\,\text{m}$ since the year $2000$.

Management of Frozen Environments

• Local Engineering: Glacier blankets (Rh\u00f4ne Glacier, Switzerland) can reduce melting by $60\,\%$. Artificial snow production is used in Austria but requires high energy and water.

• Global Governance:

  • Antarctic Treaty ($1959$): Signed by $60\,\text{nations}$ to ensure Antarctica is used only for peaceful scientific research, banning mining and military activity.

  • Arctic Council ($1996$): Involves eight nations and Indigenous groups (e.g., Inuit Circumpolar Council) for sustainable management.

  • Paris Agreement ($2015$): Global commitment to limit warming to $1.5\,^\circ\text{C}$.

Questions & Discussion

• Discussion Prompt from Lesson 5: "Which cause of deforestation is hardest to stop?" Cattle ranching is often cited due to high global demand for beef and its role in providing rural jobs in Brazil.

• Discussion Prompt from Lesson 10: "Fisherman of Fiji" Case Study Analysis.

  • Environmental impact: Coral bleaching and polluted runoff from sugarcane farms turned the reef white.

  • Social/Economic impact: Fisherman Samuela must travel twice as far for half the catch; younger villagers are migrating to cities.

  • Community response: Implementation of "tabu zones" (no-take areas) to allow fish and coral to recover.

• UN Role-Play: Discussion on the legal status of "climate refugees." There is currently no legal recognition under international law (which covers conflict/persecution), raising questions of global justice for nations like Kiribati.

• Australia-Kiribati Partnership: Australia has provided over $A\$98\,\text{million}$ for education/infrastructure and $US\$150\,\text{million}$ to help Kiribati access international climate finance.