1. The electrical energy used to light a house might go through the following sequence of conversion steps (assuming the fuel resource to be coal).

i) One tonne of coal is completely burned to produce steam in a boiler that has an efficiency of 88%;

ii) The hot, high-pressure steam passes through a steam turbine that has an efficiency of 38%;

iii) The spinning turbine drives a generator that has an efficiency of 93%; iv) The transmission lines from the generator to the house deliver electricity with an efficiency of 96%;

v) That delivered electrical energy powers a LED light bulb that converts it into visible light with an efficiency of 24%.

Ultimately, what fraction (expressed in %) of the primary energy in that original tonne of coal actually contributes to lighting the house? What happens to the rest of the energy? [2 Marks]

2. The Coastal GasLink pipeline project would see natural gas shipped to the West coast for eventual transport to Asia. As you may be aware, it is being opposed by some indigenous groups in British Columbia, and has been criticized by many for enabling the continued use of fossil fuels and the associated carbon dioxide emissions. Describe the reasons why an environmentalist might argue that this natural gas pipeline will contribute to lower carbon emissions and so should be built. [2 Marks]

3. The Fukushima nuclear reactor accident caused the environmental release of significant amounts of radioactive caesium (Cs) isotopes. Specifically, caesium-134 and caesium 137, which have half-lives of, respectively, two years and 30 years. The survey of soil radioactivity conducted in June 2011 revealed soil surface Cs-134 activity of about 500,000 Bq/m in the town of Okuma (roughly 10 km from the stricken power plant) and Cs-137 activity of roughly the same level. Disregarding any other changes or cleanup efforts since then,

a) In what year will the total level of soil radioactivity due to these two radioisotopes (combined) have dropped to 25% of its original value? [1 Marks]

b) What would you expect the radioactivity due to Cs-134 to be in Okuma today compared to its original level in June 2011? (Semi-quantitative statements are sufficient.) Explain. [2 marks]

4. Your friend is terribly afraid of radiation, so naturally her wealthy and mischievous younger brother offers her a choice for her birthday: 1) a day-long walking tour of Okuma (during which she may wear a mask) where the residual radiation dose (from the 2011 Fukushima accident, 10 km away) averages roughly 4 micro-Sieverts per hour above normal background, OR 2) dinner in far-from-Fukushima Tokyo where fresh fish caught just off the coast of Fukushima prefecture and rice grown near Okuma will be served. In the absence of any other information, which option would you advise your friend to choose, and why? (There is no secret third option...) [2 Marks]

5. When individuals are asked about the environmental impacts of cars, it is common to hear as a part of the answer some vague statement about "air pollution". But, specifically, what kind of air pollution is associated with personal automobiles? (What are the main primary and secondary pollutants produced?) And what is currently done to control it? [In the event that this topic isn't covered in class, then first read Chapter 20, sections 1-3, of the textbook.] [3 Marks]

6. The Sun delivers roughly 1360 W/m of electromagnetic (EM) power to the top of the atmosphere, but the amount of EM power received at the Earth's surface is about 33% greater than that on average. Explain how this can be. [2 Marks]

7. Canada's emissions of greenhouse gases represent roughly 2% of total global emissions, putting us in 11th place globally. In contrast, China and the United States (which rank 1 & 2) contribute 28% and 15% of the global total - figures are from 2019. However, Canada is ranked 5th in the world (2018) on the basis of greenhouse gas emissions per capita (per person). Canada has signed onto the Paris Accord, under which we commit to reducing our total greenhouse gas emissions by 30% below 2005 levels by the year 2030. The most recent figures reveal that Canada will struggle to achieve that target. From the point of view of keeping long-term global climate change to a minimum, how important is it that Canada meets its carbon dioxide goal? Does it matter if we miss those targets? What is your view? Explain. [4 Marks]

8. It took only four years following the discovery of the Antarctic ozone hole in 1985 (and 16 years after the possibility of a problem was first raised) for concrete action to be taken in the form of the Montreal Protocol prohibiting the manufacture and use of several ozone-depleting substances (mostly CFCs). Suggest reasons why the global problem of ozone depletion was so rapidly addressed while the equally global problem of climate change remains a matter of deep division with only slow & uncertain progress made so far. Why has there been no similar success on the climate change front? [3 Marks]