Increasing populations: Air pollution and habitat destruction

Carbon dioxide

A greenhouse gas produced when fossil fuels are burnt

Methane

A greenhouse gas produced by cows and from rice fields.

The enhanced greenhouse effect

The additional warming of the Earth's surface caused by increased levels of greenhouse gases that absorb infrared radiation

Effects of enhanced greenhouse effect

More frequent extreme weather conditions (e.g. heat waves, cyclones, more powerful tropical storms, etc.)

Some areas to become more drought affected, while other areas become more prone to periods of heavy rainfall

Changes to circulating ocean currents - which may cause longer El Nino (warming) and La Nina (cooling) events

Desertification

The process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture.

Populations have increased due to:

* increased medical care + vaccinations

* Clean water supply

* Improved housing

* Better food production and storage methods

Soil erosion

An effect of deforestation. The soil is moved away by water and wind.

Decreased Biodiversity

An effect of deforestation. A loss of different species in an area.

Pesticides

Chemicals used on plants that do not harm the plants, but kill pests and insects.

Monoculture

A farming strategy in which large fields are planted with a single crop, year after year.

Selective breeding

Choosing organisms with desired traits/characteristics to be parents of the next generation

Disadvantages of intensive livestock production

Poor welfare of animals and diseases spreading easily