Human Impact on the Environment

Industrial Revolution A. Rapid Human Population Growth has had a major negative impact on the environment Industrial Revolution Medical Advancements Farming Advancements

1. Estimated population size as per the U.S. Census Bureau: a. World: 7.2 billion Global Population Growth Population size Year Doubling Time 1 billion 4 billion 2 billion 8 billion 1975 1850 1930 2017 all history 80 years 42 years 45 years b. United States: 319 million 2. Overpopulation is at the root of nearly all environmental problems such as pollution and resource depletion.

B. Biodiversity 1. Number of different organisms in an ecosystem 2. Increased biodiversity  a. Increased Stability b. Genetic variation for survival during environmental changes c. Potential medicines & food crops

C. Water Problems 1. Thermal Pollution: nuclear power plants dump hot waste water into rivers/lakes  decreases dissolved oxygen  fish suffocate/die

Nuclear

Chernobyl, Ukraine 1986

Fukushima, Japan 2011

2. Fertilizers: supply nutrients to help plants grow; runoff into streams/rivers Rapid plant/algae growth (Algal Bloom/Eutrophication)  Lots of algae die  Lots of decomposers deplete oxygen  Fish suffocate/die

3. Pesticides – used to kill insect pests (Ex. DDT) a. May also harm/kill harmless insects/animals b. Can be taken in by producers and then passed through a food chain  Biomagnification (chemicals increase in concentration as they pass from one trophic level to the next)

D. Land Problems 1. Littering of Nonbiodegradable Wastes – cannot be broken down (plastic, aluminum, glass, diapers)

2. Deforestation: Removal of Forests  Increased CO2 levels ( Global Warming)  Erosion (removal of soil by wind/water)  Habitat Destruction  Decreased Biodiversity

3. Exotic/Invasive Species Organisms imported into an area from another region No natural predators  Reproduce Rapidly  Overpopulation  Out-competes native species  Disrupts food chain/Decreases biodiversity Examples: Purple loosestrife plant, Japanese beetle, gypsy moth, zebra mussels

4. Overhunting/Overfishing/Direct Harvesting (removal of specific organisms) Endangered Species (may soon completely disappear) Could lead to the extinction of that species Passenger Pigeon Dodo Bird

E. Air Problems CFCs (Chlorofluorocarbons) – used in aerosols, refrigerators, air conditioners  Ozone Depletion *Allows more UV radiation to reach Earth’s surface (causes skin cancer)

a. Air Pollution  lung cancer, heart disease, asthma 2. Burning of fossil fuels (coal, oil, natural gas) by cars and factories a. Air Pollution  lung cancer, heart disease, asthma b. Increased greenhouse gases (i.e. CO2) causes Global Warming (Global Climate Change)

b. Increased greenhouse gases (i. e. CO2) b. Increased greenhouse gases (i.e. CO2) causes Global Warming (Global Climate Change)  changes in climate/weather patterns (warmer environments that organisms can’t live in, more frequent intense storms, drought, wild fires,)  polar ice caps & glaciers melt  rise in sea level (flooding) & habitat loss  sea ice melts  polar bears can’t reach their prey & die from starvation

1909 2004 McCarty Glacier, Alaska

1909 2000 Toboggan Glacier, Alaska

c. Release of Sulfur Dioxide & Nitrogen Dioxide causes Acid Rain (rain with low pH) Harms aquatic ecosystems Harms plants Damages limestone & marble buildings

F. Ways to Fix the Problems 1. Educate the public 2. Tradeoffs: Costs vs. Benefits 3. Environmental Laws: Protected Habitats Regulate Overhunting/Overfishing Control/Limit Pollution Prevent importation of foreign species 4. Reforestation – replant trees

5. Conservation of Nonrenewable (fossil fuels) and some Renewable (trees) Resources Reduce, Reuse, Recycle Alternate (renewable) energy sources – solar, wind, water, etc.

Geothermal

Alternative Energy Sources for Electricty Production Pros Cons Potential meltdown can irradiate an area making it inhospitable (ex. Chernobyl) Dangerous nuclear waste Efficient High-yielding Nuclear Power Renewable Free energy source No pollution Currently…. Solar (photovoltaic) Not very efficient Expensive technology Renewable Free energy source No pollution Large footprint Aesthetically displeasing Migratory birds may die Wind Efficient and renewable Free energy source No pollution Hydroelectric (Dams) Disrupts river ecosystems No longer economical Renewable Free energy source No pollution Can only use near thermal “hot spots” (for high energy yield) Geothermal

controlling insect populations without using pesticides 6. Biological Pest Controls - controlling insect populations without using pesticides a. Release natural predators b. Pest-resistant plants c. Insect Traps (Pheromones) d. Release sterilized male insects