Topic 9.3 Notes – Technological Advances: Debates About the Environment After 1900

How Human Activity Reshaped the Environment After 1900

People had damaged environments before 1900, but this era turned local damage into a planetary pattern. Fossil fuels, machines, mass production, and global trade made it possible to cut, mine, pump, and transport nature at huge scale.

The causation pattern shows up again and again:

human demand → technology or state policy → resource extraction or landscape change → environmental damage → social and political conflict

Different forces worked together:

• Population growth raised demand for food, water, energy, housing, and consumer goods.
• Industrialization meant more coal, oil, natural gas, mining, shipping, electricity, and emissions.
• Urbanization packed people, factories, cars, sewage, and waste into dense spaces.
• Green Revolution farming increased food output, but irrigation, fertilizers, and pesticides strained soil and water.
• Globalization linked consumers far away to rainforest clearing, oil drilling, mining, and export crops.
• States pushed dams, roads, irrigation systems, industrial growth, and settlement in both capitalist and communist countries.

That’s the AP move here. Technology solved problems and created new ones.

Major Environmental Changes and Their Effects

Deforestation

Forests were cleared for logging, cattle ranching, soybeans, mining, roads, and settlement.

Forest disturbance in the Amazon basin

Effects included:

• biodiversity loss because habitats disappeared
• soil erosion because tree roots no longer held soil in place
• water-cycle disruption that changed rainfall and river systems
• carbon release that added to global warming
• harm to forest peoples whose land and livelihoods were damaged

The standard example is the Amazon in Brazil. The map reinforces the key pattern you should remember. Forest disturbance clusters along road corridors, showing how highways opened the interior and helped ranching, logging, mining, and soy farming spread through a mix of state policy and global demand.

Desertification and land degradation

This means dry land becomes less productive. It came from overgrazing, overcultivation, deforestation, bad irrigation, groundwater depletion, and drought.

Effects included food shortages, weaker pastoral life, migration, and fights over land and water.

The standard case is the Sahel. Drought mattered, but so did population pressure, farming on marginal land, and policy failures.

Declining air quality

Coal plants, factories, cars, oil refining, and household fuels released pollutants such as particulate matter, sulfur dioxide, nitrogen oxides, carbon monoxide, lead, and ozone.

London smog

Effects included respiratory disease, smog, acid rain, and low visibility. This photo captures the kind of urban smog that became deadly in industrial cities. The Great Smog of London in 1952 killed thousands and pushed Britain toward the Clean Air Act of 1956.

Freshwater depletion and pollution

Agriculture used the most freshwater, especially through irrigation. Dams, cities, and industry increased withdrawals too. Pollution came from sewage, fertilizers, pesticides, mining runoff, plastics, and oil spills.

Examples you should know:

• Nile basin competition over shared river water
• Exxon Valdez in 1989 and Deepwater Horizon in 2010 as major oil-spill cases

The Aral Sea as the Best Case Study

This case pulls the whole topic together. The before-and-after satellite view makes the scale of the damage easy to see.

Aral Sea, before and after shrinkage

1. The Soviet state wanted more cotton.
2. It diverted the Amu Darya and Syr Darya rivers for irrigation.
3. Cotton output rose in the short term.
4. The Aral Sea shrank and became saltier.
5. Fisheries collapsed, toxic salt dust spread, jobs vanished, and health got worse.
6. After the Soviet Union collapsed, water disputes grew among new states.

This matters because it was a human-made crisis, not a natural disaster. One development plan created desertification, pollution, economic collapse, and conflict at the same time.

Greenhouse Gases and the Climate Change Debate

The greenhouse effect is natural and keeps Earth warm enough for life. Human activity strengthened it.

The greenhouse effect

Major greenhouse gases:

• Carbon dioxide from coal, oil, gas, and deforestation
• Methane from livestock, fossil-fuel production, rice farming, and waste
• Nitrous oxide from fertilizers and industry

Effects of climate change include rising temperatures, melting ice, sea-level rise, changing rainfall, stronger heat and drought risk, ocean acidification, species stress, and displacement.

Debates you need to know:

• Scientific debate existed, but the consensus supports human-caused warming
• Fossil fuels drive economic growth, yet they create long-term environmental costs
• Rich and poor countries argue over responsibility, often using common but differentiated responsibilities
• Environmental justice matters because poorer, Indigenous, and marginalized groups often suffer more
• Responsibility is debated among states, corporations, and consumers

Agreements:

• Kyoto Protocol (1997) set binding targets mainly for developed countries
• Paris Agreement (2015) used national pledges and aimed to keep warming well below 2°C, while pursuing 1.5°C

Why These Changes Increased Competition and Conflict

Environmental pressure made people compete more intensely over water, forests, farmland, fisheries, minerals, and energy. These conflicts could involve states, upstream and downstream river users, farmers and pastoralists, or corporations and Indigenous communities.

Results included migration, displacement, higher food and water prices, compensation demands, and international negotiations.

The key nuance is that scarcity does not automatically cause war. Institutions, inequality, and state policy shape whether people cooperate, negotiate, migrate, or fight.