Fragile environments Flashcards
ecological footprint
a measure of the amount of land area required to provide people with water, energy, waste and food
carbon footprint
the amount of carbon dioxide used, created and released into the atmosphere as a result of the activities of an individual, organization or country
desertification
the process by which fertile land becomes desert due to the loss of top soil
7 characteristics of desertification
- absence of surface water
- lowering of the water table
- decreased precipitation and increased evaporation - arid conditions
- increased soil erosion
- bare soil is exposed to wind - decrease in vegetation
- can’t photosynthesise - decreased soil quality
- salinity and texture loss due to reduced humus content - salinization
- mineral salts brought up by capillarity as a result of high evaporation
7 Causes of desertification
- overgrazing
- destroyed vegetation - overcultivation
- exhausts soil and nutrient depletion so crops will not grow - soil erosion
- less support for vegetation - deforestation
- roots no longer bind soil, leading to soil erosion - population pressure
- increased by migration - less predictable weather
- civil war
Impacts of desertification
Social
- famine, malnutrition, migration, conflict
Economic
- agricultural decline(crops fail and livestock die)
environmental
-soil erosion and broken nutrient cycle
Dealing with desertification
- educate
- reduce soil erosion
- Fuelwood
- Water conservation
- changing farming
Reducing soil erosion examples
afforestation- introducing trees to improve the humus content and canopying the ground
e.g. The great green wall of Sahel
Water spreading weirs
Extend from one side of a valley to the other
Stops flow of river down a slope, but allows water to overflow to next stone line
Speed of water is reduced so soil is deposited
Water seeps into the ground, raises the water table and extends the cultivatable area
7 Causes of deforestation
- Agricultural plantation for one crop
- soybeans, sugar cane or palm oil - cattle ranching
- mining for iron, gold and copper
- road building
- commercial logging
- hydroelectric power
- settlers farming
7 Impacts of deforestation
- displacement of indigenous people
- loss of potential medicines
- soil erosion
- loss of biodiversity
- pollution of rivers
- CO2 emissions and loss of carbon sinks
- economic development
Sustainability
meeting needs without compromising the ability of future generations to meet their own needs, avoiding the depletion of natural resources in order to maintain an ecological balance
7 aspects for sustainable management of deforestation
- respecting local culture and environment
- provide income for local communities
- protect biodiversity
- involve local people to give them control over their land and lives
- use traditional skills and knowledge
- use appropriate technology
- limited pollution
10 methods for sustainable management of deforestation
- national parks
- carefully planned and controlled logging of forests
- selective logging of valuable trees
- replanting forested areas
- heli-logging
- developing alternative energy supplies
- agroforestry
- ecotourism
- substitution of some forest resources
- acai, latex, brazil nuts - reduce amount of logging licenses
agroforestry
combining crops and trees
heli-logging
uses helicopters to remove cut trees, to reduce damage done to rest of the forest
Organisation conserving the rainforest
ARPA - amazon region protected area IBAMA- protection against illegal logging and mining since 1989 US-Brazil partnership REGUA- replanting project The Forest Code
UN forum on forests
ITTA - international tropical timber agreement
CITES- convention on international trade in endangered species
UNFF- united nations forum on forests
Natural causes of climate change
- solar radiation variations
- volcanic activity
- cosmic material
Solar radiation variation
Milankovitch theory
- changes in the shape of the earth’s orbit around the sun
- changes in the tilt of the earth’s axis(obliquity)
- wobbles as the Earth spins on its axis(precession)
every 100,000 years they combine so Earth experiences a glacial period
volcanic activity
large eruptions cause global dimming
- ash reflects solar radiation back into space causes decrease in temp
cosmic material
huge meteors and asteroids eject large amount of dust into the atmosphere
-global dimming
anthropogenic causes of global warming
greenhouse gases
Greenhouse gases
carbon dioxide
methane
nitrous oxides
Chlorofluorocarbons
source of methane
decay of organic matter
waste in landfill sites
animal manure
rice growing
sources of chlorofluorocarbons
released from aerosols, fridges and air conditioning
Greenhouse effect
Electromagnetic radiation as short wavelengths passes through the Earth’s atmosphere
The Earth absorbs most of the radiation and warms up
The Earth radiates energy as infrared radiation(longer wavelength)
The greenhouse gases absorb the waves
The lower atmosphere warms up
melting ice sheets
decreased albedo
less sunlight is reflected so temperature increases
-positive feedback loop
make resources such as oil, natural gas and minerals accessible
Response to global warming
- reducing greenhouse gas emissions
- investing in renewable energy sources(off-shore wind farms)
- nuclear power
- Paris agreement Nov 2016 - committed to keep warming to less than 2 or 1.5°C
Hadley cell
- The equator is hit by vertical solar rays from the sun, meaning their is high levels of insolation. Temperature increases and pressure decreases(equatorial low pressure belt)
- Hot, moist air rises into the atmosphere near the Equator due to the high temperature.
- As the air rises, it cools.
- This sudden coolness of the air allows water to condense from gas to liquid and so high precipitation occurs as it drops its moisture as heavy tropical rains.
- The resulting cooler, drier air mass meets the tropopause, moves sideways, away from the Equator.
- As it approaches the tropics, the air descends and warms up again, (abiotically) meaning less condensation.
- The descending air hinders the formation of clouds, so very little rain falls on the land below meaning it becomes very arid(sub-tropical high pressure)
climate change
long-term shifts in temperatures and weather patterns
Uk plan
1.4% of global GHG emmissions
signed up to Kyoto Protocol
Own Climate change act- commit to cutting by 80% from 1990 levels
Uk response
- reduce reliance on fossil fuels(85%) by burning more gas than coal
- more efficient energy usage… consumption fallen by 18% since 2005
Brazil conserving rainforest
- Forest code- 1965. Requires all landowners to maintain up to 80% of their property
- Amazon Region Protected Area- 45million hectares made into parks and reserves
- REGUA- replanting
- US- Brazil partnership- brazil promised to restore 12mill hectares of land
