1. Resources and Our Environment

2. Environmental Resources
Earth's environment includes all of the resources, influences, and conditions at Earth's surface
Vital resources to life: air, water, land, and sunlight
Vital economic resources:coal and oil, metal ores
Renewable resources can be replaced in nature at a rate close to the rate of their use, such as
→ oxygen, trees, food grown in soil, solar energy
Nonrenewable resources exist in a fixed amount or are used up faster than they can be replaced in nature
→ metals: gold, silver, iron, copper, and aluminum.
→ nonmetals: sand, gravel, limestone, sulfur
→ energy sources: coal, oil, natural gas, uranium

3. Air Air is a renewable resource
78% Nitrogen, 21% Oxygen, 1% argon, carbon dioxide, and other gases
Respiration: the process by which oxygen is combined with food molecules to produce energy, water and carbon dioxide
Photosynthesis: the process by which plants use light to convert carbon dioxide and water into sugars and oxygen

4. Air Pollution
Pollution occurs when some part of the environment is changed in a way that makes it unfit for human, plant, or animal use
Air picks up chemicals or particles called pollutants
Most potential pollutants come from human activities
Sulfur dioxide comes from burning fossil fuels, and causes acid rain
Many gases produced in vehicles are poisonous
Natural sources of air pollution include forest fires, dust from soil, pollen, volcanic eruptions, and sea spray

5. Land and Soil ~ 29% of Earth’s surface is land
How humans use land depends on steepness, climate, and soil conditions
Soil is a mixture of mineral matter, decaying organic matter, water, air, and living organisms
Soil fertility is the ability of soil to grow plants
Less that 25% of the Earth’s land can be used to grow crops

6. Problems in Land and Soil Use
When the rate of erosion exceeds the rate of topsoil formation, the soil becomes a nonrenewable resource
Erosion is most prevalent on steep slopes where plants have been removed
Topsoil is renewed at a rate of a few inches every decade
Soil depletion removes nutrients from the soil
Salinization is caused by the evaporation of water, leaving behind dissolved salts
Land is a limited resource, there is only so much available

7. Water
Over 70% of Earth’s surface is covered by water, 97% in the oceans
Ocean water is too salty for growing crops or for drinking
Most uses of water require fresh water from lakes, rivers, and groundwater
The water cycle replenishes the fresh water
Quantity of water is a challenge
Quality of water is also a challenge

8. Water pollution
Pollution from industrial waste and domestic waste increases the pressure on water supplies
Pesticides, sewage, oil leaks and spills, and contaminated water all find their way into the water supply
Phosphates and nitrates from fertilizers and detergents enter lake and ocean water
Eutrophication is the unusual growth of algae and other microscopic organisms
Oxygen using organisms eat the algae and deplete oxygen from lakes and the ocean, fish and other animals die
Germs from sewage may pollute and cause disease
Poisonous waste from factories causes a build up of poisons in fish
Thermal energy is also a pollutant