Core Theme 3 - Patterns in Environmental Quality + Sustainability Flashcards
What is the Global Energy Budget?
The balance between incoming energy from the sun and outgoing energy to the atmosphere
What is insolation?
Incoming solar radiation
What is albedo?
The ability of a surface to reflect light. The higher the albedo, the more light reflected
How has carbon dioxide contributed to the enhanced greenhouse effect?
- CO2 levels risen from 315ppm (1950) to 355ppm today
- expected to reach 600ppm by 2050
- increase due to human activities e.g. burning fossil fuels + deforestation
How has methane contributed to the enhanced greenhouse effect?
- 2nd largest contributor to global warming
- increasing at rate of 1% per annum
- cattle convert 10% of food they eat into methane + emit 100million tonnes methane into atmosphere per annum
- methane-rich paddy fields emit 20-100 million tonnes annually
- w inc. in global warming, bogs trapped in permafrost will melt + release vast quantities of methane
How have CFCs contributed to the enhanced greenhouse effect?
- increasing at rate 6% per year
- 10,000 times more efficient at trapping heat than CO2
Implications of climate change
- sea levels will rise, causing flooding in low-lying areas e.g. netherlands, bangladesh: up to 200 million people could be displaced
- storms will increase due to more atmospheric energy
- changing agricultural patterns (USA’s grain belt will decline but Canada’s growing season will increase)
- less rainfall over USA, southern Europe + CIS
- up to 40% of wildlife species will become extinct
What proportion of soil degradation can be attributed to water erosion?
Water erosion accounts for 60% of soil degradation. There are many types of water erosion inc. surface, gully, rill and tunnel erosion
What is acidification of soils?
Acidification is the change in the chemical composition of the soil, which may trigger the circulation of toxic metals
What are the causes of land degradation?
- reduction of natural vegetative cover
- unsustainable land-use practises
- groundwater over-abstraction, leading to dry soils
- atmospheric deposition of heavy metals + organic pollutants
What proportion of soil degradation is due to overgrazing?
35%
What proportion of soil degradation is due to deforestation?
37%
Loess Plateau: Background
- Loess Plateau used to have fertile soil + ideal agricultural conditions, which contributed to development of early Chinese civilisation
- plateau devastated by years of overexploitation
- had one of highest erosion rates in world
- 95% rainwater lost as surface runoff
- only in 1995 recognised as critical area for 90 million inhabitants
- without fundamental intervention land would be unliveable
What was the Loess Plateau Watershed Rehabilitation Project?
With US $500million from World Bank, the Loess Plateau Watershed Rehabilitation Project was created with the primary objectives of sustainably improving agriculture, decreasing sediment flows into the Yellow River. and increasing incomes for the local economy.
What did the Loess Plateau Watershed Rehabilitation Project do?
- Planted with a range of trees, shrubs + grasses to achieve land stabilisation and production of much-needed fuel, timber and food
- Construction of sediment retention dams in the Yellow River reduced sediment runoff from slope lands and gullies in the nine watersheds. Rather than the water running down and continuing to cause erosion by carrying soil particles with it, the water is trapped so that it can be utilised effectively
- Farmers living there were paid for their labor and therefore their lives were being rehabilitated simultaneously with the plateau.
What were the impacts of the Loess Plateau Watershed Rehabilitation Project?
- More than 2.5 million people in four of China’s poorest provinces were lifted out of poverty
- Farmers’ incomes doubled and in some cases quadrupled, employment diversified and the degraded environment was revitalised
- Replanting and bans on grazing allowed the perennial vegetation cover to increase from 17% to 34%.
The removal of vegetation + topsoil frequently results in:
- increased surface runoff + stream discharge
- reduction of water infiltration + groundwater recharge
- development of erosional gullies + sand dunes
- change in surface microclimate enhancing aridity
- drying up of wells + springs
- reduction of seed germination of native plants
Why are the impacts of soil degradation more severe in developing countries?
- primary is often main sector of employment in LEDCs e.g. agriculture
- with less fertilised land + drying up of wells, less crops can grow destroying economies + communities as they are more vulnerable
