Chapter 1 Notes: Understanding Our Environment

Case Study: Can We Restore the Amazon?

• Tremendously important ecosystem and carbon sink: stores $20\%$ of world’s tree biomass.

• Transpiration from rainforest trees releases water vapor to the atmosphere, supporting high rainfall.

• Rainforest shrinking dramatically due to human activities: burned down for ranching and farming; impacts include oil extraction and mining.

• Source attribution: ©Navajo Tribal Utility Authority.

Earth: A Remarkable Planet

• Conditions on Earth are unique:

  • Temperatures mild, relatively constant.

  • Plentiful clean air, fresh water, fertile soil.

  • All regenerated by biochemical cycles and biological communities.

• Earth is self-sustaining.

Is Earth’s Environment Changing?

• Questions to consider:

  • Are hurricanes becoming more intense?

  • More species extinctions?

  • Major droughts and wildfires more severe?

  • Emerging diseases as a threat?

• Example: Hurricane Beryl makes landfall in Texas (08/2024).

What’s “The Environment?”

• Circumstances or conditions that surround an organism or group of organisms.

• Complex system of social or cultural conditions that affect an individual or community.

What’s “Environmental Science?”

• Use of scientific approaches to understand natural systems around us.

• Study of interrelationships.

• Interdisciplinary and holistic – natural sciences, social sciences and humanities.

What are the major environmental challenges today?

Major Themes in Environmental Science

Climate Change: Crises and Opportunities

• Over the last 200 years, humans greatly increasing concentrations of CO₂ and other greenhouse gases.

• Mean global temperatures predicted to increase by $2-6^{\circ}C$ by 2100.

• Efforts to find solutions may foster better international cooperation and new innovations.

Biodiversity Crises and Opportunities

• Biodiversity Loss: Why?

  • Outcompeted by invasive species and exotic organisms.

  • Habitat destruction.

  • Pollution.

  • Overexploitation.

• Species are disappearing today at rates comparable to the “Great Extinction Event” at the end of the dinosaur era.

Energy Resources Crises and Opportunities

• Fossil fuels supply $80\%$ of energy in developed countries.

• Burning fossil fuels contributes to climate change.

• Renewable energy and energy conservation could slow climate change.

Water Quality Crises and Opportunities

• Clean water: Lack of clean water contributes to >$15\times 10^6$ deaths annually.

• $1.1\text{ billion}$ humans lack access to safe drinking water.

• $40\%$ of humans live in countries where water demand exceeds resources.

• Since 1990, $800+\text{ million}$ people gained access to improved water supplies and modern sanitation.

Air Quality Crises and Opportunities

• Air quality worsening dramatically in some regions, esp. China & India.

• Millions of early deaths; rising cancer rates from pollution.

• U.N. estimates >$2\times 10^9$ metric tons of air pollutants released/year (excluding CO₂ or wind-blown soil).

• U.S. & Europe effectively reversed deadly air pollution decades ago by enforcing policies, pollution controls & efficient technology.

Human Population Crisis and Opportunities

• Population growth: >7\text{ billion} people on Earth; ~$80\text{ million}$ added annually.

• Infectious disease cases dwindled in last 100 years; life expectancy ~doubled.

• Since 1960, avg. number of children born per woman decreased from $5.0$ to $2.45$ worldwide.

• Populations now stabilized in industrialized & poor countries (where social security, education & democracy established).

• Present trends project world population will stabilize at $8-10\text{ billion}$ by 2050.

Human Food Supplies Crisis and Opportunities

• Hunger and food insecurity: $60+\text{ million}$ people face acute food shortages due to weather, politics, or war.

• $2/3$ of all agricultural lands show signs of degradation.

• Over the past century, global food production increased faster than human populations.

• In most countries, obesity-related diseases more common than hunger-related diseases.

• During the population spike in the 1990s, the number of people facing food insecurity/chronic hunger declined by about $40\text{ million}$.

Habitat Preservation Crises and Opportunities

• Conservation of forests and nature preserves:

  • Deforestation dramatically slowing in Brazil (previous leader in deforestation).

  • Brazil is now working to protect forests.

• Worldwide, $13.5\%$ of the world’s land area is now protected.

Marine Resources Crises and Opportunities

• Marine Resources: >1\text{ billion} people depend on seafood for protein.

• $75\%$ of 441 fish stocks are severely depleted or need better management (World Resources Institute).

• Better monitoring of Marine Protected Areas (MPAs) supports more sustainable management.

• Marine reserves are now common, established in California, Hawaii, New Zealand, Great Britain, and elsewhere.

Human Education and Well-Being Crises and Opportunities

• Information and Education:

  • Expanding literacy, access to education.

  • Internet access makes sharing environmental solutions easier.

  • Expanding education for girls drives birth rate decline.

  • Rapid information exchange promotes increased global awareness of environmental issues.

Central Theme of this Course: Sustainability & Sustainable Development

• Sustainable Development:

  • Provides for current needs without compromising future needs.

  • Encourages resiliency and adaptability.

  • Addresses uneven distribution of resources.

World Wealth Unevenly Divided

• $10\%$ of the world’s population have incomes over $40{,}000/yr$ (Europe, North America, Japan, Singapore, Australia, etc.).

• >$70\%$ of the world’s population (≈$5\text{ billion}$) have incomes less than $40{,}000/yr$ (China, India, sub-Saharan Africa, etc.).

• Per capita income in different regions (in 2010 U.S. dollars).

Indigenous People Safeguard Biodiversity

• ~$500\text{ million}$ indigenous people remain in traditional homelands.

• They possess valuable ecological wisdom; many live in little-disturbed habitats.

• These habitats are refuges for rare/endangered species and undamaged ecosystems.

What’s Science?

• Attempt to discover order in the natural world and use that knowledge to describe/predict what will happen in nature.

• Based on observations/experiments.

• Fundamental assumptions:

  • Events in the world follow orderly patterns.

  • Careful observation and experimentation help us understand these patterns.

• Benefit: Use science to identify practical solutions to many problems.

The Scientific Method: Step 1

• Observation/Question: Oh, my plant is dead. Why did my plant die while I was away?

The Scientific Method: Step 2

• Formulate a hypothesis (conditional explanation):

  • Example: My roommate did not water it; too much water; too much sun; too little sun.

The Scientific Method: Next Steps

• Test hypothesis:

  • Make a prediction.

  • Collect data (experimentation or observations).

  • Demand reproducibility!

• Revise your prediction; collect additional data if necessary.

• Interpret your results (consult/compare with others’ prior results).

• Publicize your findings, let others review (peer review).

The Scientific Method: Terms

• Hypothesis = conditional explanation/answer.

• Scientific theories = well tested and accepted hypotheses; supported by an overwhelming body of data and experience.

• Scientific (natural) laws = well tested and accepted, broadly applicable scientific theories.

• Note: Scientific theory and scientific law are not the same!

The Scientific Method (Summary Figure)

• 1 Identify question

• 2 Form testable hypothesis

• 3 Develop a test of the hypothesis

• 4 Collect data; compare with previous studies

• 5 Interpret results

• 6 Report for peer review

How have ideas about the environment changed? What does it matter if…

• Honeybees are dying off in massive numbers?

• Polar bears are going extinct in the wild?

• I buy international products grown on fields created by cutting down rainforest, or manufactured in factories which release their dangerous pollutants into streams and rivers, rather than treating the waste?

• Let’s explore some major ideas and contributions of environmental leaders of the last century, up to the present…

Pragmatic (Utilitarian) Resource Conservation

• Triggered by wanton resource waste and destruction.

• Key figures:

  • George Perkins Marsh (wrote Man and Nature, 1864), raised awareness of nations’ need for environmental stewardship.

  • Theodore Roosevelt and chief conservation advisor Gifford Pinchot.

• 1873: U.S. National Forest Reserves established (later Forest Service created).

• Promoted “utilitarian or pragmatic conservation” (i.e., mainly for humans’ use of a resource).

• Pinchot generally opposed conservation for the sake of wilderness or scenery itself.

Preservation Movement

• Key figures: John Muir, Aldo Leopold.

• Belief: Preserves should exist for their own sake; opposite of Pinchot’s utilitarian vision.

• Opposing views: Environment as a commodity belonging to us vs. a community to which we belong.

• John Muir: first president of the Sierra Club.

• Aldo Leopold: formulated the land ethic; founded the Wilderness Society.

Preservation Movement Emphasizes Fundamental Right of Other Organisms

• Emphasis on intrinsic value of non-human life and ecosystems.

Modern Environmental Movement

• Rise of pollution concerns led to the modern movement.

• Book Silent Spring (Rachel Carson, 1962) highlighted pesticide impacts.

• Focus on both natural resources and pollution, threats to humans and other species.

• Led to environmental lobbying and activism; expanded in the 1970s.

Global Environmentalism: Environmental Quality Tied to Social Progress

• Activists connect environmental quality with social progress on a global scale.

• Concepts like a green-collar economy (jobs in solar energy, energy efficiency).

• Notable figures: Van Jones, Bill McKibben (350.org).

• Dr. Wangari Maathai and the Green Belt Movement in Kenya as an example of sustainable development.

Quick Chapter 1 Review (Key Points)

• Scientific Method, Hypothesis, Scientific Theory, Scientific Law.

• Pragmatic (Utilitarian) Resource Conservation (Roosevelt, Pinchot).

• Preservation Movement (Leopold, Muir).

• Modern Environmental Movement (Carson, Silent Spring).

• Global Environmentalism tied to social progress.

• Sustainable development as a central concept.