B-6.6: Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and processes of Earth. Human Impact

“4 Minutes” by Madonna (with Justin Timberlake) “There is a sense of urgency… that we are living on borrowed time essentially and people are becoming much more aware of the environment and how we’re destroying the planet.” – Madonna interview with MTV Madonna wrote the song “4 Minutes” because she felt a sense of urgency to save the planet from destruction

Activity Working with a partner, your task is to solve some of the world’s toughest problems Each group is only responsible for 2 to 3 issues. You only have 4 minutes to save the world!!!

Humans and the Ecosystem Humans play a role in ecosystem and cycles People depend on resources and cycles of Earth to provide clean water, breathable air, and good soil Human activities are affecting the cycles and Earth processes: Population growth Technology Consumption of resources

Carrying capacity Carrying capacity: maximum population size that can be supported by the available resources Various factors determine the carrying capacity of humans Energy Water Oxygen nutrients

Sustainability Sustainability  meeting the needs of humans to survive indefinitely Needs to be a balance between Earth’s resources and carrying capacity, needs of humans, and needs of other species on Earth Factors that affect sustainability: population growth, technology, consumption of resources

Population Growth Grown exponentially Prediction: will continue to grow at a rapid rate Natural slowing of population growth as it nears its carrying capacity is due to increase in death rate and decrease in birth rate due to: Food and water shortages Pollution diseases

Population Growth - water Increasing population affects amount of water produced If clean water is being depleted at a greater rate than it can be purified, it is not considered renewable in our lifetime

Population Growth - waste An increasing population can affect amount of waste There are mechanisms to control the disposal of waste products, but more waste is produced than can be managed Some waste products require complicated and costly means of removal

Population Growth – fertile soil An increasing population can effect amount of available fertile soil for food resources (agriculture) Soil is often lost when land is cleared, making land unsuitable for agriculture Worldwide demand for land (agriculture or habitation) has led to deforestation Forests cut down, less carbon dioxide absorbed leading to increase in global warming Deforestation can increase rate of erosion (wind and water) and decrease rate of soil generation

Worldwide, about ½ of the area once covered by forests is now cleared Compare the before and after for Asia

Human population growth When these resources become scarce, many natural processes are affected Water cycle Carbon cycle Nitrogen cycle Physical processes of soil regeneration

Technology Technology used to find solutions to problems Technology has been a benefit but also contributed to: pollution of air, water and land For sustainability, technology has provided cleaner energy sources, safer ways to deal with waste and better methods for cleaning up pollution Technological advances in agriculture, industry, and energy can have a positive or negative impact on Earth

Agricultural technology Improve ability to grow crops to sustain growing population Help conserve fertile soil and reduce soil erosion Farm machinery consume renewable resources and can contribute to erosion and air pollution Addition of substances (fertilizers, pesticides, fungicides, livestock waste) to environment can alter composition of soil and have a negative/positive effect on water, carbon or nitrogen cycles

Industrial technology Lead to developments in communication, transportation and industry Development of certain chemicals (CFCs) contribute to depletion of ozone layer (increasing UV rays reaching Earth) CFCs: chlorofluorohydrocarbons, used in producing foam packing materials, cleaning electronics, and refrigeration chemicals

The Greenhouse Effect

Industrial technology Technological advances revolutionized communication industry; however disposing of outdated or damaged equipment is a concern

Industrial Technology – burning fossil fuels Burning fossil fuels increases sustainability of growing population, however, It increases greenhouse gases, which increases temperatures which affects sea levels, climate and atmospheric composition It produces acid rain Acid rain decreases pH of soil and nutrients can leave soil Acid rain changes pH of aquatic ecosystems

Acid Rain

Industrial technology – alternative energy technology Using natural renewable energy sources decreases burning of fossil fuels and increases quality of atmosphere Renewable resources: wind, water, geothermal, or solar energy Using nuclear energy provides alternative energy that does not impact atmosphere However, there is a concern about nuclear energy waste

Nuclear Energy

Consumption of Resources As population increases and technology expands, demand for earth’s resources increases Limited supply of these resources to sustain population Some resources are renewable resources (production = consumption) Food, clean water, and timber Some factors limit their production Example: grain is limited by amount of land available, fertility, etc.

Consumption of Resources Some resources are nonrenewable resources (consumption > production) Fossil fuels Demand for minerals, metals and ores increases for industry but are decreasing in availability Minerals are nonrenewable resources because mineral deposits can be extracted are formed so slowly Sustainable use of resources can be accomplished by reducing consumption, reusing products rather than disposing of them or recycling waste to protect the environment