HUMAN IMPACTB-6.6: Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and

processes of Earth.

“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 growthTechnologyConsumption of resources

Carrying capacity

Carrying capacity: maximum population size that can be supported by the available resources

Various factors determine the carrying capacity of humansEnergyWaterOxygennutrients

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 shortagesPollutiondiseases

Population Growth - water Increasing population affects amount of

water producedIf 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 agricultureWorldwide 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 affectedWater cycleCarbon cycleNitrogen cyclePhysical 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 atmosphereHowever, there is a concern about nuclear energy

waste

Nuclear Energy

Consumption of Resources

As population increases and technology expands, demand for earth’s resources increasesLimited supply of these resources to sustain

population Some resources are renewable resources

(production = consumption)Food, clean water, and timberSome 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 fuelsDemand for minerals, metals and ores increases for

industry but are decreasing in availabilityMinerals 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