Planetary Health: Resources, Energy, and Pollution
Environmental Impact: Our Wounded Planet
Resource Exploitation
Natural resources are elements from nature that humans utilize for their benefit.
Resource Classification
- Renewable Resources: Inexhaustible resources like solar, wind, and tidal energy.
- Non-Renewable Resources: Finite resources like oil, coal, and natural gas.
- Potentially Renewable Resources: Resources that can be renewed depending on human exploitation and regeneration rates, such as agricultural, livestock, and fishery resources.
Water: Earth’s Life Blood
Water covers three-quarters of our planet. However, only 2.5% is freshwater, much of which is trapped in polar ice.
The Hydrosphere
The hydrosphere comprises Earth’s seas, rivers, lakes, groundwater, ice caps, and glaciers. The water cycle, driven by solar energy and gravity, circulates water throughout the planet.
Water Usage
Humans have always relied on water. Agriculture consumes the most freshwater (73%), significantly more than industry and energy production (21% combined).
- Domestic and Public Consumption: Cleaning, drinking, watering parks, and other public uses.
- Agriculture: Crop irrigation (flood, sprinkler, and drip methods).
- Energy Production: Hydroelectric power generation.
- Livestock: Animal hydration and waste cleaning.
- Industry and Mining: Manufacturing processes, cooling systems, and power plants.
Energy: Clean and Conserved
Non-Renewable Energy
- Coal: Carbon-rich mineral formed from decomposed plant material. It’s the cheapest energy source but highly polluting, contributing to greenhouse gases and acid rain. Primarily used for electricity generation.
- Oil: Essential resource for gasoline, diesel, plastics, etc. Reserves are dwindling, and production costs are rising. Most reserves (65%) are in the Middle East.
- Natural Gas: Mixture of gases like methane and hydrogen, formed from decomposed organic matter. Cleaner burning than oil with larger reserves.
- Nuclear Power: Energy generated from uranium fission in nuclear power plants.
Renewable Energy
- Solar Energy: Converting sunlight into usable energy. Solar thermal absorbs solar heat for heating, while photovoltaic solar is highly profitable and rapidly growing.
- Hydropower: Utilizing river or waterfall power for electricity generation in hydroelectric plants.
- Wind Power: Wind turbines harness wind energy to generate electricity.
- Tidal Energy: Utilizing ocean currents.
- Geothermal Energy: Harnessing Earth’s internal heat.
- Biomass Energy: Utilizing organic matter from agriculture, livestock, and urban waste.
- Hydrogen Energy: Burning abundant hydrogen releases energy and water.
- Nuclear Fusion: The energy source of the sun and stars.
Pollution: Environmental Alteration
Pollution is the alteration of the environment by physical, chemical, or biological agents in concentrated amounts.
Water Pollution
Caused by agricultural and livestock waste, wastewater, and industrial byproducts.
- Nutrients: Essential for aquatic plant growth, but excessive amounts lead to overgrowth.
- Oxygen-Demanding Waste: Substances that consume oxygen.
- Pathogens: Bacteria and viruses from organic waste.
- Salinity: Mineralized water from soil, rocks, or industrial waste.
- Heavy Metals: Toxic in high amounts, entering the food chain and posing health risks.
- Organic Compounds: Pesticides, plastics, and volatile organic compounds.
- Thermal Pollution: Heat from industrial cooling processes.
- Sediment: Insoluble particles from erosion.
The Greenhouse Effect
Caused by carbon dioxide and water vapor. Essential for life but excessive amounts lead to global warming.
Solar radiation heats Earth, which emits infrared radiation. Greenhouse gases trap this radiation, warming the planet.
Smog: Urban Air Pollution
Smog (smoke + fog) is air pollution caused by specific weather conditions and pollutants.
Industrial Smog
Gray smog from burning coal and oil, containing sulfur dioxide, sulfuric acid, and particulate matter. Less common in developed countries now.
Photochemical Smog
Ozone (O3): Formed from oxygen molecules, toxic in high concentrations. The ozone layer in the stratosphere protects us from UV radiation.