Geography Deforestation

Limits to growth model uses 5 factors that grow at an exponential rate:

Population, industrialization, pollution, food production and resources

Ability of technology to increase resources grows only linearly

As population increases, resources decrease

Food and industrial output grow exponentially until resources and food run out and pollution increases

Population then crashes - predicted to happen in 2010

The world's population has risen from two billion in 1930 to 6.8 billion now, with nine billion projected by 2050.

The burgeoning human population is acknowledged as one of the underlying causes of environmental issues such as climate change, deforestation, depletion of water resources and loss of biodiversity.

- The population has doubled in Ethiopia. And this is putting stress on the land , pushing people further up the mountains to the margins of fertility. The thin soil is exhausted; the trees that bound it to the hillsides have long since been chopped down for firewood. When

When it is dry it blows away as dust, when it rains the topsoil is swilled away by rivers.

Aim: To know effects of and solutions to deforestation

Effects of deforestation

Water cycle

* Decrease in infiltration --> more overland flow --> flash flooding

* Greater turbidity of water - more murky

* Water temperature increases

Atmosphere

* Reduction in water evaporated from trees

Soil and nutrients

* Top soil removed

* Nutrients washed away

* Soils compacted

* Decrease in infiltration --> more overland flow --> flash flooding

* Sandification - raindrops wash away fine particles of clay leaving course sand behind

* Greater turbidity of water - more murky

Biological diversity

* Detritivores washed away with soil

* Loss of species diversity

* Habitats are degraded

* Loss of pollinators