Environmental Science 1401
henrylin815
ch011.pptxEnvironment
Tenth Edition
Raven
Chapter 1
Introducing Environmental Science and Sustainability
Introducing Environmental Science and Sustainability
Overview of Chapter 1
Human Impacts on The Environment
Population, Resources and the Environment
Sustainability
Environmental Science
Addressing Environmental Problems
Food as a Lens for Our Relationship to the Environment
Chicken sandwich requires: wheat, chicken, other ingredients, pesticides, fertilizers, energy (petroleum) to manufacture, transport, treat generated wastes, and make packaging, landfills
Our individual choices affect the environment
How could we adapt our food-production practices for greater sustainability?
The Environment (Earth)
Life has existed on Earth for 3.8 billion yrs.
Earth well suited for life
Water over ¾ of the planet
Habitable temperature, moderate sunlight
Atmosphere provides oxygen and carbon dioxide
Soil with essential minerals for plants
Modern humans appeared in Africa only 100,000 years ago
Increasing Human Numbers
In 19 50, eight cities had populations > 5 million
N Y C - 12.3 million
In 2016, large urban agglomerations of cities
10 largest metropolitan areas, total of 200 million
Tokyo, Japan – 17.8 million, with 38.1 in greater metropolitan area
Human Population Growth
In 2017, human population is: 7.5 billion
Passed 7 billion in 2011
Growing exponentially
Estimates of 9.3 -10.5 billion by end of 21st century
In areas with fast growing populations, quality of life for many people may worsen considerably
Population and Extreme Poverty
More than 1 in 2 people live in extreme begin underline poverty end underline
Cannot meet basic needs for food, clothing, shelter, health
< $2.50 per U.S. dollars day
Fertility rates worldwide
children per family
Expected to decline and stabilize by end of 21st century
Difficult to meet population needs without exploiting Earth’s resources
Countries Differentiated Based on Wealth
Highly Developed Countries (H D C)
Complex industrialized bases, low population growth, high per capita incomes
Ex: U.S., Canada, Japan
Less Developed Countries (L D C)
Developing countries, low level of industrialization, high fertility rate, high infant mortality rate, low per capita income (relative to highly developed countries)
Ex: Bangladesh, Kenya, and Nicaragua
Income Disparity Between Rich and Poor
Rising income disparity in many countries
Large gap between wealthy and poor citizens
Differential access to electricity, cars, modern medicine
Recently, greater disparity between urban and rural citizens in L D C
Ex: China, India, Brazil, Mexico
Total wealth of country less accurate in describing well-being of citizens
Population, Resources, and Environment: Needs for Survival
Two useful generalizations:
1. Essential resources for individual survival are small
However, rapidly increasing population can quickly overwhelm or deplete, especially locally
Individual Resource Consumption
2. Individual resource consumption can far outweigh needs of survival
Affluent nations use larger portions and can exhaust resources globally
Types of Natural Resources
Natural Resources
Renewable Natural Resources
Direct solar energy
Energy of winds, tides, flowing water
Fertile soil
Clean air
Fresh water
Biological diversity (forests, food crops, fishes)
Nonrenewable Natural Resources
Metallic minerals (gold, tin)
Nonmetallic minerals (salt, phosphates, stone)
Fossil fuels (coal, oil, natural gas)
Resource Consumption
Human use of materials and energy
Economic and social act
People in H D Cs are big consumers
Unsustainable Consumption
When level of demand on resources damages or depletes resources enough to reduce the quality of life for future generations
Caused by overpopulation and/or overconsumption
Ecological Footprint
The average amount of productive land, fresh water, and ocean required to continuously provide that person with all the resources they consume
| Earth’s Productive Land and Water | 11.4 billion hectares |
| Amount Each Person is Allotted (divide Productive Land & Water by Human Pop.) | 1.5 hectares |
| Current Average Global Ecological Footprint | 2.7 hectares |
Ecological Overshoot
Humans have a global ecological overshoot
Ecological Footprint Comparison
Large variation in footprints among countries
I P A T Model
Model - represents a system; describes the system as it exists and predicts how changes in one part of the system will affect the rest of the system.
Average Fuel efficiency in U.S.
Average fuel economy
22.1 mpg (19 88)
20.4 mpg (2000)
S U V popularity
24.8 (2015)
Hybrid popularity
Passenger car efficiency increased by
since 19 80 (left)
Sustainability Requires Long-term Perspective
Ability to meet current human economic and social needs without compromising the ability of the environment to support future generations
Sustainability Requires Long-term Perspective
Focus on Sustainability
Stabilize human population
Prevent pollution where possible
Restore degraded environments
Protect natural ecosystems
Use resources efficiently
Educate all boys and girls
Prevent and reduce waste
Eradicate hunger and poverty
Sustainability and Human Behavior
Not often operating sustainably because of behaviors:
Extract resources as if they are unlimited
Consume faster than resources are replenished
Pollute at high rates
Increase population despite finite resources
Tragedy of the Commons
Garrett Hardin (19 15–2003)
Solving environmental problems is result of struggle between:
Short-term welfare
Long-term environmental stability and societal welfare
Common-pool resources
Garrett used common pastureland in medieval Europe to illustrate the struggle
Sustainability works best with collaborative stewardship
Sustainable Development- Systems Concept
Economic development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs
Summits helping to form international approaches
Environmental Science
Interdisciplinary study of humanity’s relationship with other organisms and the nonliving physical environment
Biology
Ecology
Begin underline Geography
Chemistry
Geology
Physics
Economics
Sociology
Demography
Politics
Earth’s System and Environmental Science
System
A set of components that interact and function as a whole
Global Earth Systems
Climate, atmosphere, land, coastal zones, oceans
Ecosystem
A natural system consisting of a community of organisms and its physical environment
Systems in a dynamic equilibrium with feedback among components
Negative Feedback
Negative feedback
Change in some condition triggers a response that counteracts (reverses) the changed condition
Positive Feedback
Positive feedback
Change triggers a response that intensifies the changing condition
Ex: polar and glacial ice melt, color change leading to more rapid melting
Science is a Dynamic Process
Science is a systematic way to investigate the natural world
To manage and produce information
Scientists collect objective data through observations and experiments, and make conclusions
Published work is peer reviewed
Process by which scientific findings are scrutinized and validated or rejected by other experts in the field
Helps to self-correct errors
Scientific Method
The way a scientist approaches a problem by formulating a hypothesis and then testing it by means of an experiment
Controls and Variables in Experiments
Variable
A factor that influences a process
May be altered in an experiment to determine its effect on the outcome
Experimental group
Chosen variable is altered in known way
Control group
Variable is not altered
Allows for comparison between the tests of when we alter the variable and when we do not alter the variable
Scientific Knowledge and Theory
Theory
An integrated explanation of numerous hypotheses, each supported by a large body of observations and experiments and evaluated by the peer review process
Simplifies, clarifies, and predicts our understanding of the natural world
Absolute truth is not possible in science
Varying degrees of uncertainty
Knowledge evolves as new evidence is found
Climate Change: Hypotheses and Theory
C O2 and other gases from burning fossil fuels affect climate
Unable to test or run large experiments globally
Must acquire lots of data and adapt theories and understanding with new data
Many parts of climate theory are tested
C O2 and rise in atmosphere
Impact of gases on solar radiation
Addressing Environmental Problems
Five steps represent ideal approach
Scientific assessment
Risk analysis
Public engagement
Political action
Long-term evaluation
Reality is untidy
Often, public pushes for a solution
Environmental Science in Practice: Lake Washington
Large, deep freshwater lake
Suburban sprawl in 19 40’s
10 new sewage treatment plants dumped treated effluent, high in nutrients, into lake
Effect = excessive growth of cyanobacteria
Bacterial decomposition of cyanobacteria depleted O2
Scientific Assessment of Lake Washington
Scientists from University of Washington studied problem and collected data
Study informed Washington Pollution Control Commission (19 55)
Commission concluded that effluents added nutrients to Lake, particularly phosphorus
Nutrients caused growth of cyanobacteria
Cyanobacteria decomposed by bacteria depleted O2
Low O2 reduced fish and small invertebrates
If pollution stopped, lake would recover
Recovery Plan for Lake Washington
Many political hurdles in passing a plan
Accepted bill was most ambitious and expensive pollution control project in U.S. at the time
Treated sewage was diverted into trunk sewer that ringed lake (starting in 19 63)
Eventually discharged into Puget Sound, where it would have less effect
By 19 75, lake was healthy and water was clear
Today, work to reduce waste generation in view of greater population around lake
Data on Recovery of Lake Washington
~3
~50%
