Spec Info

Ecological Footprint

Sustainability

‘Actions and forms of progress that meet the needs of the present without reducing the ability of future generations to meet their own needs’

What factors affect a countries' footprint?

• The ecological footprint is a measure of the area needed to support a population’s lifestyle. This includes the consumption of food, fuel, wood, and fibres. Pollution, such as carbon dioxide emissions, is also counted as part of the footprint.

Therefore the footprint is affected by:

• Industry• Development • Environmental policies• Population• Transport• Pollution

Soil Erosion- What is it and why do we care?

"The threat of nuclear weapons and man's ability to destroy the environment are really alarming. And yet there are other almost imperceptible changes - I am thinking of the exhaustion of our natural resources, and especially of soil erosion - and these are perhaps more dangerous still, because once we begin to feel their repercussions it will be too late." (p144 of The Dalai Lama's Little Book of Inner Peace: 2002, Element Books, London)

Deserts and Desertification

Deserts of the World

Some key terms and definitions.

• Drought - the destruction of soils and vegetation in arid

(dry) regions

• Desert - an extended period of drier weather than is usual (in the Sahel this

can last for more than 10 years)

• Desertification - A dry area, hot or cold, where total annual precipitation is less than 250 mm. Usually treeless

Examples of a case study question

With reference to a named example, explain the causes and consequences of desertification.

C Describes the causes and consequences

B Begins to explain the causes and consequences with some reference to the Sahel

A/A* Detailed explanation of the causes and consequences with specific reference to the Sahel.

TASKS: 1. Describe the location of the Sahel. Refer to continent, latitude, desert, etc. (if this was an exam question, it would be worth 4 marks)

Where is the Sahel?

Why does the Sahel suffer from desertification?

DESERTIFICATION

Increase in population Increase in cattle

Deforestation for fire wood Grassland grazed more intensively

Roots no longer hold soil together Roots may be eaten as well as grass

Leaves no longer protect soil from weather Less vegetation means less protection from weather

Loose top soil blown away by wind

(Soil Erosion)

=

Loose top soil blown away by wind

(Soil Erosion)

=DESERTIFICATION

Solutions to the problem of desertification?Restore and fertilize the land A simple and cheap way to fertilize the land is to prepare compost, that will become humus and will regenerate the soil with organic matter.

Combat the effects of the wind By constructing barriers and stabilising sand dunes with local plant species. Reforestation Trees play several roles: they help fix the soil, act as wind breakers, enhance soil fertility, and help absorb water during heavy rainfall. Because the burning of land and forests increases dangerous greenhouse gases, afforestation – planting new trees - can help reduce the negative impacts of resulting climate change. Develop sustainable agricultural practices Drylands are home to a large variety of species, that can also become important commercial products: for example, they provide 1/3 of the plant-derived drugs in the United States. Agriculture biodiversity must be preserved. Land overexploitation shall be stopped by leaving the soil ‘breathe’ during a certain-time period, with no cultivation, nor livestock grazing. Traditional lifestyles Traditional lifestyles as practiced in many arid zones offer examples of harmonious living with the environment. In the past, nomadism was particularly adapted to drylands conditions; moving from one waterhole to another, never staying on the same land, pastoral peoples didn’t exert much pressure on the environment. However, changing lifestyles and population growth are putting increasing pressure on scarce resources and vulnerable environments. The Silk Road in Asia and the Trans-Saharan route in Africa are good examples of the vigorous economic and cultural exchanges developed by nomadic societies.

Solutions to the problem of desertification?Fertilize the land to restore it

• To combat desertification it is necessary to restore and fertilize the land. Nutritive elements such as nitrogen, phosphorus, calcium, magnesium etc. in the soil are necessary for plants to grow. When the soil has lost all its nutritive elements or a part of its constituents (removed by wind or water) it is said to be degraded or exhausted and its productivity diminishes as a consequence. It can also accumulate such toxic elements as salt that need to be eliminated.

• As these elements become exhausted through intensive agriculture it becomes necesssary to re-establish soil fertility either by using synthetic fertilizers or by preparing much cheaper compost. It is principally prepared from plant waste: manure, agricultural trimmings (straw), and biological household waste. Water hyacinths, though harmful in rivers, can be transformed into fertile matter that supplies nutritive elements to the soil as compost. After several weeks in a pit, and with the heat and humidity, humus is produced. It can then be spread among the crops and used to prepare the soil before seedlings are planted. The soil regenerated with organic matter in this way will produce more fruitful harvests. The restructuring of the soil is a very effective and particularly sustainable way to maintain soil fertility.

• The presence of livestock could also be exploited to enrich the soil. By consuming crop leftovers the animals return nutritive elements to the soil that enriches it with nitrogenous matter in the form of dung. Dung also restores the capacity of soil to produce a more plentiful harvest. The herd also provides meat and milk. In this way, farmers and cattle rearers can help each other.

Combating the effects of windSome simple mechanical means to alleviate the effects of wind that prevent the displacement of sand and dust, include: • the construction of fences or barriers from local plant species: woven palms, planted hedges (rows of maize or millet that protect beans and onions) or metal sheeting around villages and crops.• planting vegetation whose roots protect and fix the soil. • prohibiting livestock from grazing to protect the areas of plantation. ReforestationThis requires the creation of nurseries to nurture young plants among local species selected for their rapid growth and adaptation to the harsh climate. Reforestation is a long-term action since tree growth is slow. Trees play several roles:• they fix soil elements and prevent their loss by water and wind. • they act as obstacles to the wind (wind-breaker) to protect crops (trees should be pruned to be more effective). • they enhance soil fertility: many trees produce nitrogen (due to the presence of bacteria in roots) that fertilizes and increases soil productivity. • they facilitate water penetration into the soil during the rains and contributes to maintaining humidity for a long time. • they provide shade for animals and people. •they supply nutritive elements: fruit trees diversify food sources, trees provide fodder for livestock (during the dry season).

Substituting woodA large number of populations use wood as their major source of energy, which contributes further to desertification (through deforestation) and increases the greenhouse effect (by releasing carbon dioxide). The non-sustainable use of forest resources (firewood) as a source of energy is a factor leading to desertification. Therefore, identifying and employing alternative renewable energy sources is important in the fight against desertification. Non-polluting and renewable energies can replace wood at limited or no cost (the energy source is free) and they can easily be used by families in villages.

e.g. Solar energy:Bright sunny conditions, characteristic of arid regions, can satisfy energy needs in these areas. Solar energy can be used in multiple ways:

• parabolic mirrors help cook food, produce water vapour and run electric water turbines. • panels transform sunrays into electricity. The electric current is stored in batteries and can be used day or

night. Despite the present high cost, it is hoped that this option will become more affordable in the future. • the evaporation power of the sun can produce distilled water, free of salt and germs, by using a solar

distiller.e.g. WindThe force of the wind can drive wind propellers that produce electricity. The wind energy can generate a pump to extract water from wells, fill watering holes or irrigation basins or activate mills to transform grain into flour. This type of energy will facilitate land irrigation and the supply of water to the livestock. e.g. BiogasThis is a gaseous mix produced in a fermentation tank that comes from the decomposition of dung and plant waste. The leftovers from the fermentation can be used as natural fertilizer (compost). The high temperatures in the drylands are beneficial to the creation of biogas. Its advantages: it is uncostly and can be used for lighting, cooking or to drive motors (generators, tractors and cars). Biogas can also be produced in small installations. This technique can most effectively be developed in regions where agriculture and cattle rearing coexist.

Developing education and training It is important that every individual has access to information and understands the action proposals communicated by the media and literature. Reading and writing skills provide people the opportunity to become better informed and help them understand and organize projects that combat desertification. Education therefore enables them to share knowledge and better manage the available resources.

Location of tropical rainforests

Starter: Copy and complete:

Deforestation is the cutting down of trees. Many primary forests in temperate countries have almost disappeared after centuries of logging (cutting down trees for timber) and land clearance (usually to plant crops). However it is only fairly recently that large-scale deforestation has started to take place in the world’s tropical rainforests. The future welfare of the tropical rainforests is an important issue.

Why is the rainforest so fragile?

• Rainforest ecosystems are characterised by heavy convectional rainfall, high humidity, lushness of vegetation and nutrient-rich but shallow soil. These factors give rise to a unique water and nutrient cycle.

Deforestation in the Amazon

Deforestation in the Amazon has been going on for centuries. The local Indians used “Slash and Burn” to clear small parts of the forest to grow crops on. Since the area cleared was small, the damage was minimal and the jungle eventually took over the land once again.This damage was sustainable because it was very few people, clearing very small patches of the rainforest.

But today...

Deforestation is now carried out at a much greater scale, and it is no longer sustainable

because the forest is not given time to recover.

Why is the Amazon being chopped down?

v

A

B

C

D

Why protect?????CO2

Carbon dioxide produced by burning fossil fuels is taken in by treesThis helps to reduce carbon in the atmosphere, reducing global warming

And……

The greenhouse effect…

NOT

NOT and

Is But

Where do these gases come from?

Carbon Dioxide

Methane

CFCs

Nitrous Oxide

Works like….

Without it……

33°c

Evidence…….?

• Fact 1!

• Fact 2!

Global Impacts….

The human modified greenhouse effect

Evidence---Sea Levels Rise

13m7m 84m

Global coastal flooding Maldives Coastal FloodingLoss of tourism – many coastal areas are popular tourist destinations. Flooding can cause tourist attractions to close and it can put people off visiting.

Loss of tourism – tourism is the largest industry in the Maldives. If the main airport can’t work properly because of coastal flooding the country will be cut off from international tourists. This will massively reduce the country’s income

Damage repair – repairing flood damage can be extremely expensive.

Loss of beaches – coastal flooding wears away beaches on the islands at a rapid rate. This destroys habitats and exposes the land behind the beach to the effects of flooding

Loss of agricultural (farming) land – sea water has a high salt content. Salt reduces soil fertility, so crop production can be affected for years after a flood.

Loss of soil – the soil on most of the islands is shallow (bout 20cm deep).coastal floods could easily was away the soil layer, which would mean most plants won’t be able to grow

Deaths- coastal floods have killed thousands Houses damaged or destroyed – a severe flood could make entire communities homeless

Water supplies affected - floodwater can pollute drinking water with salt and sewage

The Maldivian Government had to ask the Japanese Government to give them $60 million to build a 3m high sea wall that protects the capital city Male

Loss of housing – many people are made homeless because of floods

Changes to long-term plans – the government is thinking about buying land in countries like India and Australia and moving Maldivians there before the islands disappear

Loss of jobs – coastal industries may be shut down because of damage to equipment and buildings e.g. Fishing boats can be destroyed

Changes to environmental policies – increased flooding is cased by rising sea level which is caused by global warming. The Maldives has pledged to become carbon neutral so it doesn't contribute to global warming and encouraging other governments to do the same.Ecosystems affected – seawater has a high salt content.

Increased salt levels can damage or kill organisms

Vegetation killed by water – the force of flood water uproots trees and plants. Standing flood water also drowns some trees and plants

Disrupted fishing industry – fish are the Maldives’ largest export. Coastal flooding may damage fish processing plants, reduce fish exports in turn reducing the country’s income

Increased erosion – a large volume of fast-moving water can erode lots of material, damaging the environment

Less fresh water available – supplies of freshwater are already low on many of the islands. If supplies are polluted with salty water during floods, then some islands will have to rely on rain water or build expensive desalination plants to meet water demandsThe government has to make policies to reduce the impacts

of future flooding. They can do things like building more or better flood defences or they can manage the use of areas that might be flooded, e.g. By stopping people living there.

International efforts to prevent global warming