VMBO Year 2 · HAVO/VWO Years 2–3 · Ecology and sustainability · Section 6.5
People and the environment
Environmental influences
People remove substances from the environment, such as raw materials, and add others, such as waste. Population size and patterns of consumption influence the scale of these effects.
Two important problems are:
- Resource depletion: Using natural resources faster than they can be replaced, or using up finite resources such as fossil fuels.
- Pollution: Introducing substances or other influences at levels that harm air, water, soil or living organisms.
Resource depletion
Some raw materials and fossil fuels are finite. Poorly managed farming can also deplete soil nutrients.
A monoculture grows one crop over a large area. Repeatedly removing the same crop without replenishing nutrients can reduce soil fertility.
Pollution
Examples include:
- Air pollution: Particulate matter, exhaust gases and reactive nitrogen compounds from sources such as traffic, industry and agriculture.
- Soil pollution: Harmful contamination from waste, industry or farming.
- Water pollution: Manure nutrients, wastewater and chemicals entering waterways or groundwater.
Some harmful substances enter food chains. Pesticides can also contaminate soil and water if they move beyond their intended target or persist in the environment.
The enhanced greenhouse effect
Greenhouse gases, including carbon dioxide and methane, absorb and re-emit infrared radiation, slowing heat loss to space. The natural greenhouse effect keeps Earth warmer than it would otherwise be.
Human activities increase greenhouse-gas concentrations. Burning fossil fuels releases carbon dioxide; activities including livestock production and fossil-fuel extraction can release methane.
This enhanced greenhouse effect causes additional warming.
Climate change
Warming changes climate and affects ecosystems. Examples include:
- Cyanobacterial blooms: Warm, nutrient-rich water can favour some toxin-producing cyanobacteria, sometimes leading to swimming restrictions.
- Sea-level rise: Seawater expands as it warms, and melting land ice adds water to the oceans.
- Salinisation: Freshwater or soils become saltier, which can damage salt-sensitive crops.
- Ecological changes: Flowering times, species distributions and feeding relationships can shift.
Glossary
- Cyanobacteria
- Photosynthetic bacteria, sometimes called blue-green algae; some form blooms and produce toxins.
- Soil pollution
- Harmful contamination of soil by substances from waste or other sources.
- Greenhouse effect
- Warming caused by atmospheric gases slowing the loss of heat to space.
- Greenhouse gases
- Gases such as carbon dioxide and methane that absorb and re-emit infrared radiation.
- Pesticides
- Substances used to control pests, weeds or diseases, with possible unintended environmental effects.
- Fossil fuels
- Fuels such as coal, oil and natural gas formed from ancient organic material over geological time.
- Raw materials
- Natural substances used to make products.
- Climate change
- Long-term changes in climate; current global warming is mainly driven by human greenhouse-gas emissions.
- Air pollution
- Harmful substances in air, including particles and certain gases.
- Environmental problems
- Damage to the environment, including pollution and resource depletion.
- Minerals
- In this plant-nutrition context, inorganic nutrients taken up from the soil.
- Monoculture
- Growing a single crop species over an area, often repeatedly.
- Sea-level rise
- An increase in average sea level, caused partly by warming seawater and melting land ice.
- Nitrogen
- An essential element; excess reactive nitrogen compounds can harm ecosystems, unlike the abundant nitrogen gas that makes up most air.
- Resource depletion
- Using up resources or consuming renewable resources faster than they recover.
- Enhanced greenhouse effect
- Additional warming caused by increased concentrations of greenhouse gases.
- Salinisation
- Increasing salt content in soil or freshwater.
- Pollution
- Introducing harmful substances or influences into the environment.
- Water pollution
- Contamination of surface water or groundwater by wastes, nutrients or chemicals.