Environmental impact and planetary boundaries Flashcards
What is environmental monitoring?
- The quality of the environment it describes the current status and when done repeatedly the pattern of the data can be used to identify trends and make predictions
Environmental monitoring:
Air Quality
- The concentrations of air pollutants are measured because of health effects associated with exposure to them
- Air pollution is carried by the wind so this must be taken into account when identifying sources of pollution
Environmental monitoring:
Soil monitoring
-Looks at the soil structure and density, its water holding and drainage capacity, pH, organic particles earthworms and other organisms as implied by measuring enzyme activity and respiration rate
Environmental monitoring:
(Chemical) Water quality
The concentration of environmental oestrogens in water supplies has increased as a result of the use of oral contraceptives and of materials used in industry
- They have a feminising effect on some aquatic organisms and it is suspected that they might influence humans as well, both in embryo development and iin timing of puberty
Environmental monitoring:
(Biological) Water monitoring
- Many animals act as indicator species for water quality, e.g. brown trout in rivers indicate high quality water
- Steep decline in salmon population is an indicator for acid rain
- mosses can indicate heavy metal concentrations
- Eels are used to study halogenated organic chemicals, which accumulate in their fat
Environmental monitoring:
(Microbiological) Water monitoring
- Bacteria and viruses are monitored, especially in drinking water or water used for sports
- Many sewage treatment plants do not sterilise the water used for sports
- Many sewage treatment plants do not sterilise the water they release
- So water entering a river may look clean but have a very high bacterial count
Environmental impact assessment
- Statistical analyses of environmental monitoring data , performed by dedicated software packages, mean that data collected can contribute to environmental impact assessment
- These are document that aim to predict environmental effects of a proposed project when activities risk harming the environment, e.g. road building
In the EU environmental impacts assessment were introduced in 1985. Among the topics they address are:
- A description of the project and site
- Alternatives that have been considered, e.g. whether the fuel in a power station burning biomass is local or not
- A description of the environment, e.g. populations, fauna, flora, air, soil, water, human use, landscape and cultural heritage. Organisations with crucial local knowledge, such as the RSPB, have input into this
- A description of significant effects on the on the environment, e.g. in a wind farm development, a significant impact may be collisions with birds
- Mitigation, i.e. ways to avoid negative impact are an essential aspect of planning. Evidence is required to show that reducing the impact of harmful activities has been considered. Counterarguments might be:
- wind farms to be built when birds are not nesting
- Proposed roads to avoid breeding ponds of endangered amphibians, e.g. the greater crested newt and the natterjack toad
Define planetary boundaries
Limits between which global systems must operate to prevent abrupt and irreversible environmental change
Planetary boundaries: The climate change boundary
- Climate change is one of the two core boundaries and its planetary boundaries has been crossed
- The effects on wind, ocean currents, rainfall patterns and precipitation
- Kyoto protocol, agreed in 1997 was the first major international agreement to address global warming
- This is done by setting targets for reducing the greenhouse gases in the atmosphere
Planetary boundaries: Biofuels
- The carbon dioxide that biofuels release during combustion has only recently been removed from the atmosphere
- Growing more biofuel crops removes the carbon dioxide from the atmosphere again
- Biofuels are made by biological process such as anaerobic digestion of plant material or agricultural, domestic and industrial waste
- They are useful in reducing the use of fossil fuels but growing plant material for them conflicts with the use of land for food production and it requires considerable irrigation
- International energy agency target is for at least 25% of the worlds transport to use biofuels by 2050
- First generation biofuels are made from cellulose and lignin from woody crops, which are harder to extract
Social, economic and technical issues relating to biofuel production:
- Carbon emissions: European bioethanol production and use reduce greenhouse gas emissions by 60-90% compared with the production and use of fossil fuels
- Sustainable biofuel production relies on sustainable planting and efficient technical systems
- Deforestation to grow biofuel crops leads to soil erosion and biodiversity loss
- Reduction in water availability, because biofuel crops require a large volume of irrigation water
- Combustion of biodiesel produces more nitrous oxide than fossil fuel
- Food vs fuel: land used to grow food has been turned over to crop production for biofuels
Bioethanol
- Bioethanol is the commonest biofuel and most car petrol engines are designed to use up 15% bioethanol with petrol
- It is made by fermenting the carbohydrates in sugar or starch crops, such as maize, sugar beets, sugar cane and sweet sorghum
- Brazil and the USA have developed bioethanol commercially, with 90% of the global production
Bioethanol is made in several stages
- Plant material is crushed and the stored starches are digested with carbohydrates to release sugars
- Sucrose is crystallised out leaving molasses, which is rich in glucose and fructose
- Glucose and fructose are fermented by yeast to produce a mixture containing ethanol
- The mixture is heated by burning the fibrous waste, or bagasse, from the initial plant material and pure ethanol is distilled
Biodiesel
- Most widely used biofuel in Europe
- ## It is made from vegetable oils including soya, rapeseed and palm oil and it can be made form algae
