Fragile Environments

Sustainability

The exploitation of the world's resources in such a fashion that the needs of the current generation are met without compromising the ability of future generations to meet their own needs

Reasons why environments are at risk

1. Population growth: Continued rapid growth in Sub-Saharan Africa means that the world population is likely to reach 11 billion by 2080
2. Increased consumption per capita: Increased global economic growth and increased global standards of living and hence consumption

Features of rainforests

1. Unique vegetative canopy structure consisting of several vertical layers including the overstory, canopy, understory, shrub layer, and ground level.
2. High levels of annual precipitation as they are located in intertropical convergence zones subject to intense solar radiation producing a convection zone of rising air that loses it's moisture through frequent rainstorms.
3. High levels of biodiversity with species interdependence and a complex symbiotic relationship

Ecological Footprint

The area of land required to support a population (or a person) at their current standard of living.

How technology can be used to reduce a population's ecological footprint without reducing their standard of living

1. Energy: Alternative energy sources, home insulation, electrical vehicles etc to reduce energy consumption
2. Materials: Find alternatives and recycle, use locally sourced materials to reduce carbon emissions required for transportation of raw materials
3. Food: Reduced meet consumption, smart irrigation systems, vertical farming etc

Soil Erosion

The physical removal of soil either by running water or the wind and it occurs when an area's vegetation is removed - in this context, due to desertification

Desertification

Desertification is the degradation of semi-arid environments into infertile arid environments because of naturally occurring droughts and human activity

Causes of Soil Erosion and Desertification: Droughts

1. Naturally Occurring Droughts
A prolonged period of water shortage due to lower than average rainfall, leading to watercourses drying up.
- Soil erodibility increases with drought duration
- Drying of soil creates cracks which reduces the moisture and volume of soil
- The action of surface runoff and wind exacerbates the rates of soil erosion in drought prone areas

Causes of Soil Erosion and Desertification: Population Pressure

2. Population Pressure
- Semi-arid areas generally have higher birth rates than death rates (alongside high fertility rates)
- Hence, rising populations also increase consumption per capita, increasing demand for resources, leading to:
-> Over-cropping: Farmers try to maximize their harvests, and often lack the capital to buy sufficient fertilizer, leaving the soil exhausted and inefficient, reducing vegetation cover
-> Overgrazing: Farmers try to maximize the size of their cattle, goat and sheep herds which reduces vegetation cover
-> Gathering firewood: People often depend on the firewood for cooking, the gathering of which depletes the cover of bushes and trees

Causes of Soil Erosion and Desertification: War/ Civil War and Forced Migration

Often because resources are being competed for by rising populations, many semi-arid areas are blighted by conflict. This leads to refugees who are often forced into vast camps and out a significant load on local food and water resources, exacerbating the other causes and degrading local environments

Solutions to the problems of soil erosion and desertification

1. Contour ploughing: Following the natural contours when tilling the soil, mitigating the impacts of floods, storms and landslides on the crops by reducing soil erosion, controlling surface runoff, and increasing soil infiltration and water retention.
2. Intercropping: Additional soil cover provided my multiple crops helps reduce soil erosion
3. Hedged cultivation plots: Hedgerow roots run deep, absorbing more water, and also act as a physical barrier to slow down wind speeds and reduce soil erosion.

How technology can reduce water shortages in fragile environments at risk from desertification

Supply:
1. Simple check dams on ephemeral streams can retain water from rainfall and replenish groundwater
2. Deep wells can access groundwater / untapped aquifers and solar powered pumps can pump from areas of surplus
Demand:
1. Smart drip irrigation systems can be used for crop cultivation
2. Water-efficient domestic supply systems can be introduced

The Sahel

A belt of semi-arid land stretching over 8000 km from Mauritania and Senegal in the West to Ethiopia and Somalia in the East along the southern fringes of the Sahara Desert

Causes of Soil Erosion and Desertification in the Sahel: Sudan

1. Droughts: High temperatures up to 48c in some areas with as little as 80mm of annual rainfall in some years
2. Population Growth
3. Warfare and forced migration: 2.5 million internally displaced people due to civil unrest. Massive refugee camps around Dafur that are slow to disperse

Impacts of Desertification in the Sahel: Southern Niger, 2010

Six month drought reached its Zenith:
1. Widespread crop failure resulting in acute food shortages, causing people to resort to famine foods
2. Nearly half a million children under five years old were suffering from acute malnutrition
3. Failure of grazing lands causing the deaths of tens of thousands of cattle
4. Large numbers of women left their husbands and migrated to main towns to work as prostitutes to earn money for food
5. 1 in 5 families left in search of food and income
6. Western aid agencies were overwhelmed by the scale of the disaster

Solutions to the problems of Soil Erosion and Desertification: Niger

1. Check dams to retain water in the summer rainy season
2. Local farmers trained to construct stone terraces to encourage infiltration and use contour ploughing, and digging Zais (cultivations pits) to encourage water retention
3. Over 10,000 seedlings have been planted and areas of woodland have been fenced to keep out livestock
4. Villagers have been taught to use hedges to keep out livestock and use inter-cropping strategies
5. Villagers were given improved cooking stoves

Deforestation

The removal of tree cover (by either burning or felling) at a faster rate than they can either regenerate or are replanted.

5 Causes of Deforestation

1. Logging/timber extraction:
- "Slash and burn" techniques traditionally used by indigenous tribes practicing shifting cultivation to clear land for agriculture
- Modern day commercial logging (for Mahogany, Teak etc.) is more destructive
2. Agriculture
- Cleared land is used for arable cultivation (by small-holders and large commercials groups e.g. for Soya)
- Or used for grazing ranches of cattle for beef production and for plantation crops like palm oil
3. Mining
- For gold, silver, copper and even iron ore are all common
- Most destructive is bauxite, where large areas of forest are cleared for strip mining
- Removal of an overburden requires the removal of tree cover, and it is difficult to replace primary rainforests
4. Hydroelectric power
- Large reservoirs have been constructed in Amazonia, India, West Africa etc. has flooded hundreds of square kilometers of forest
5.
- Although relatively small in terms of clearance, roads have been critical in opening up forest interior which has been followed by logging
- eg. The Trans Amazonia Highway constructed in the 1970s opened up the Amazon basin

5 Consequences of Deforestation

1. Loss of Biodiversity
- Loss of habitat for animal, insect and tree species
- Also houses important pharmaceuticals such as cortisone and quinine
2. Disruption to the hydrological cycle and soil erosion
- Removing tree cover reduces infiltration and vegetation interception storage, and reduced evaporation and transpiration raises the water table, increasing rates of overland flow.
- Causes rapid erosion of deep tropical soils
3. Disruption to nutrient cycling
- Rainforests have high temperatures and high annual precipitation
- This means organic litter decomposes naturally and its nutrients quickly leach into the subsoil, concentrating nutrients in the biomass
- When soil erosion removes the biomass, soil infertility follows
4. Climate Change
- Forests are among the world's largest carbon sinks, and deforestation releases carbon through burning and decomposition
- Also reduces a deforested area's ability to absorb carbon in the future
5. Economic Development
- Deforestation opens the door to economically productive activity which is able to raise the standard of living for millions living in poor countries

3 Global Scale solutions to the Problems of Deforestation

The Greenhouse Effect

Incoming, predominantly short wave, ultraviolet, solar radiation passes through the atmosphere but outgoing, predominantly long wave, infrared terrestrial radiation is absorbed by specific gases in the atmosphere.

6 Anthropogenic Causes of Climate Change

1. Agriculture:
- Emissions in the form of methane released by ruminants and the cultivation of rice paddies which provided breeding grounds for methanogenic bacteria
2. Deforestation
3. Energy Generation:
- Combustion of fossil fuels (releasing CO2) to generate electricity in coal, gas and oil fired power plants is still increasing
4. Industry:
- Industrial processes eg. steel making emit greenhouses gases
5. Transport:
- Emissions generally though the combustion of hydrocarbons or oil-based fuels in airplanes, road vehicles etc.
6. Waste Management
- Decomposition of organic matter generates methane

7 Consequences of Climate Change

1. Shifting Climatic Belts
- Sub-tropical latitudes (current deserts) will expand and become hotter and drier
- Greatest warming in high latitudes due to destabilizing of positive feedback loops which amplify warming
2. Rising Sea Levels
- Causing the erosion of beaches, inundation of deltas, loss of habitat and social displacement
3. More Extreme Weather
- Higher temperatures increase convection currents and convective storms
- Warmer air holds more moisture, increasing the likelihood of flash floods
- Also will destabilize climatic belts and increase droughts and heat waves
4. Ecosystem Changes
- Due to shifting climatic belts
- Spring and summer arriving earlier
- Allows for the spread of invasive species such as vectors for Malaria
5. Changing Settlement Patterns
- Settlements on flood plains and low lying coasts may have to be restricted or abandoned
6. Reduced Employment Opportunities
- eg. Coal mining
7. Changes in Health, Wellbeing and Food Supply
- Spread of tropical diseases to move into new temperature latitudes
- Wellbeing: Eco-anxiety
- Food supply affected due to water shortages and wildfires threatening fruit crops and plains