Global Issues Part 2 Flashcards
What is the spectral energy density?
it is the distribution of radiation energy emitted by a body across the electromagnetic spectrum.
What are the units of spectral energy density?
W m-1 or W Hz -1
What is a black body?
A black body absorbs all radiation that it may receive at any wavelength. It can be shown that such a body must emit radiation with an intensity and a SED that only depend on the Stefan-Boltzmann law.
On the diagram of spectral density - which hand side is the radiation emitted and received for the Earth
For spectral energy density, the radiation is received from the sun on the left hand side of the diagram. The radiation is transmitted to space on the right hand side of the diagram.
What is radiative forcing?
Most of the solar radiation hitting the earth will be in the form of visible light. Some will be reflected and scattered. The rest of it is absorbed by the surface and re-radiated in the infrared. The re-absorption of this re-radiated energy in the IR by some gases in the atmosphere delays re-emission back to space. The re-absorbed energy is re-radiated by the gases in al directions, thus warming the layers below. This is radiative forcing.
Which gas is mostly responsible for radiative forcing and other gases that contribute?
CO2. The less-contributing gases include water vapour, methane, nitrogen oxides and other gases.
What is the effect of a temporary increase in the CO2 concentration?
It reduces the heat flux that Earth is emitting to space.
What gives CO2 its dominance amongst other GHGs?
It has a fairly low concentration but the broad absorption band in the infrared spectrum gives its dominance.
What about water vapour and radiative forcing?
The rising temperature is increasing the overall concentration and thus amplifies the radiative forcing. However more clouds will then reflect sunlight back to space and thus mitigating the greenhouse gas effect.
What is the carbon bubble?
When looking at future prospects, the current value of fossil fuels may be seriously overinflated as more governments and businesses get on board the climate change reduction train. That gap between what fossil fuels are actually worth and what they are valued at will grow.
What could governments do to discourage the use of fossil fuels?
The aim of governments is to make fossil fuels a “stranded asset” to be left untouched. This would be by enacting regulations and implementing taxes. Thus would devalue the shares in oil and gas companies.
What is the greenhouse gas to rival CO2?
CH4
How is CH4 produced by human activity?
- Rice cultivation
- Biomass burning
- Coal mining
- Natural gas production
What was the aim of the Kyoto Protocol?
The Kyoto Protocol aimed to reduce CO2 emissions by 5% between 1990 and 2012.
Did the Kyoto Protocol meet its aims?
No the Kyoto Protocol failed. The emissions increased by half.
What are the reasons between the failure of the Kyoto Protocol?
It was not ratified by the US and Australia. It was ratified by the UK, China and India but the latter two were committed only to improving their economy.
What is the successor of the Kyoto protocol?
The Paris Agreement
What is the aim of the Paris Agreement?
Limit the average global temperature rises to below 2 oC or below 1.5 oC if possible.
How does the Paris Agreement work for each signatory?
Each signatory submits their own personally determined contributions for emission reductions. There are 195 signatories.
What are the downfalls of the Paris Agreement?
The Paris Agreement is legally binding but there is no mechanism for sanctioning results or any sort of timeliness.
What is the relationship between energy and development?
There is a linear relationship between the energy consumption of the country and the GDP
What is the ethical issue facing the nations of the world?
Sizzling the plant vs. keeping living on in poverty. Developing countries should be allowed their chance.
Engineering solutions - what does energy efficiency include?
Heat integration, combined heat and power (CHP)
Engineering solutions - what are the advantages of energy efficiency?
It makes a lot of financial sense, and industry likes it
Engineering solutions - what are the disadvantages of energy efficiency?
There is an inadequate marketing strategy (there is no incentive for landlords and tenants) and there is inadequate existing infrastructure for example for implementing district growth heating
Engineering solutions - what needs to be done to improve energy efficiency?
Strong policies and regulations that require new funding and who is going to pay?
Engineering solutions - give examples of some renewable technologies?
Wind, solar, geothermal, tidal and wave
Engineering solutions - what are the advantages of renewable technologies?
There are low CO2 emissions on a life cycle basis. The cost of offshore wind has recently been greatly reduced which now makes them highly competitive.
Engineering solutions - what are the disadvantages of renewable technologies?
It is still costly. Renewable energy sources are intermittent which means that there is often need for a back up and a baseload from conventional generation and reinforcement on power grid. There is the constant challenge of managing supply and adverse market conditions.
Engineering solutions - solutions for renewable energy technologies
- Pooling over large geographical areas
- Demand side management including smart grids to avoid blackouts of the grid
- Energy storage technologies need developing and made less costly
Engineering solutions - what are the advantages of power generation from biomass sources?
The CO2 generated by burning the fuel equals the CO2 consumed in growing it
Engineering solutions - what are the cons of power generation from biomass sources?
The fuel is bulky and costly to transport, there is low spatial yield because the crops are grown or collected over a large acreage, wet and must be dried before combustion. It also takes up land which could be used for the cultivation of crops.
Engineering solutions - solutions for power generation from biomass sources?
Small scale operations with proximity of the fuel source.
Engineering solutions - why plant trees?
Trees are planted to ‘offset’ emissions
Engineering solutions - what are the advantages of planting trees?
It is popular with public opinion and local population
Engineering solutions - what are the disadvantages of planting trees?
It is the difficulty in the scale of the enterprise, the involvement of the local people and the land use and ownership, and enforcing sustainable forestry
Engineering solutions - what are the fixes for planting of trees?
Strong policies and regulations that require new funding
Engineering solutions - what are the advantages of generating more nuclear power?
- Low CO2 on a Life-Cycle Analysis basis.
- Small self-contained modular reactor could be more economical compared with the traditional large ones
Engineering solutions - what are the cons of generating more nuclear power?
- Conventional power stations are not popular due to large-scale disasters
- Waste disposal is also an issue with public perception and uncertainty of custody with future generations.
- Decommissioning is costly
- Small reactors may fall into the hands of terrorists
Engineering solutions - what are the fixes for nuclear power?
- Safer fission technologies and fuel routes with e.g. molten salt reactors and thorium replacing uranium.
Engineering solutions - CO2 capture. How can CO2 be captured?
(a) Biomass growth
(b) Diatoms
(c) Geological storage
(d) deep water trenches
Engineering solutions - disadvantages of CO2 capture.
There is no other benefit to businesses other than not releasing carbon dioxide into the atmosphere. It would involve the instalment of expensive equipment and energy costs.
Engineering solutions - fixes for CO2 capture
Government support for de-risking and demo projects. Deal first with concentrated carbon dioxide emissions e.g. cement.
