Homework: CSE548 Global Climate Change and Society Response (Due on 6 November 2023, Monday)
Please write down your answers clearly and BOX the final results. For Q5, you may use MATLAB or Excel to compute the abundances.
1. (15 points) Multiple choice
1). In the last 130 years, the Earth has warmed approximately: a) 0.1 °C
b) 0.8 °C c) 8 °C d) 10 °C
2). Which of the following contributes the most to sea level rise so far?
a) Mountain glaciers
b) Ice shelves
c) Ice sheets
d) Thermal expansion
3). Greenhouse gases warm the Earth by absorbing and reemitting what type of energy?
a) Wind Energy
b) Shortwave Radiation
c) Longwave Radiation
d) Electricity
4). Most radiation coming from the sun is _____, and most radiation coming from the Earth is ____.
a) Microwave; longwave
b) Ultraviolet; shortwave
c) Longwave; shortwave
d) Shortwave; longwave
5). If more solar radiation is reflected back to space, it means the Earth’s albedo has
a) Decreased
b) Increased
c) Remain the same
6). If the energy leaving the Earth (Eout) is less than the energy reaching the Earth (Ein), the Earth will:
a) cool down
b) warm up
7). If the Earth’s albedo increases, the energy reaching the Earth (Ein) will ___, and the energy leaving (Eout) will ____.
a) decrease; decrease
b) decrease; increase
c) stay the same; decrease
d) stay the same; increase
8). In 1958, CO2 in the atmosphere was measured at 320 parts per million (ppm), and 63 years later (i.e. today) is approximately:
a) The same
b) 50% lower (150 ppm)
c) 30% higher (410 ppm)
d) 100% higher (640 ppm)
9). A decrease in shortwave radiation absorbed by Earth is a _____ radiative forcing, and a decrease in longwave out of Earth is a _____ radiative forcing.
a) Positive; negative
b) Positive; positive
c) Negative; negative
d) Negative; positive
10). Globally, the concentration of atmospheric CO2 is _____ than that of CH4; the lifetime of CO2 is _____ than that of CH4; the global warming potential of CO2 is _____ than that of CH4.
a) higher; longer; larger
b) higher; longer; smaller
c) lower; longer; smaller
d) lower; shorter; smaller
11). Which of the following can change in response to a climate forcing? Select all that apply.
a) Ice/snow
b) Sun activities
c) Pinatubo volcanic eruption
d) Clouds
e) Water vapor
12). Emitting black carbon into the atmosphere is _____ aerosol effect and is _____ on climate.
a) direct; positive forcing
b) direct; negative forcing
c) indirect; negative forcing
d) indirect; positive forcing
e) direct; positive feedback
f) indirect; negative feedback
13). Coral bleaching can be caused by _____. It is expected to _____ with global warming. a) Low ocean acidity; become more severe
b) High ocean temperature; become more severe
c) High ocean acidity; become less severe
d) High ocean temperature; become less severe
14). Which is a result of Arctic sea ice melting? (select all that apply)
e) Releases CH4 into the atmosphere
f) Increase of sea level
g) Decrease of Earth’s albedo
h) Stratospheric ozone hole
i) New shipping routes in the Arctic
15). During last century, the sea level has risen about _____.
a) 0.1 m
b) 1 m
c) 10 m
d) Actually stay the same
16). Why heat waves can threaten people’s lives? (Select all that apply)
a) Some cities are built for cooler times and difficult to response to sudden high temperature
b) Heat waves can bring persistently high temperature
c) The sunny and stagnant conditions during heat waves cause high concentration of air
pollutants and particles
d) Heat waves generally bring thunderstorms and heavy precipitation that cause floods
17). On a cloudy night, the temperature stays warmer because:
a) Clouds block cold air from the upper atmosphere from mixing with the warm surface air.
b) Clouds absorb longwave from space and radiate it to the surface.
c) Clouds absorb longwave emitted from the surface and radiate it back to the surface.
d) Clouds reflect shortwave from the surface.
18). Which of the following are examples of weather events? (select all that apply)
a) Tornado touching down in Joplin, Missouri
b) It was mostly sunny at HK PolyU on 30 January 2023
c) Arctic sea ice thickness reducing by 50% in the last 30 years
d) Drying of Poyang Lake
e) Typhoon Mangkhut making landfall in Hong Kong
19). The largest source of anthropogenic CO2 is from:
a) Ocean emissions
b) Trees
c) Fossil fuel burning
d) Cows
e) Human breathing
20). Which of the following is a greenhouse gas? (Select all that apply)
a) Oxygen (O2)
b) Carbon dioxide (CO2)
c) Nitrogen (N2)
d) Methane (CH4)
e) Water Vapor (H2O)
f) Hydrogen (H2)
g) Tropospheric ozone (O3)
h) Nitrous oxide (N2O)
21). What is the most abundant greenhouse gas in the atmosphere?
a) CO2
b) Water vapor
c) N2O
d) CFCs
e) N2
f) O2
22). The radiative forcing of CO2 for current value versus preindustrial (year 1750) value is about _____, which is similar to the total radiative forcing caused by all greenhouse gases and aerosols.
a) -2W/m2 b) 2W/m2 c) -20W/m2 d) 20W/m2
23). Which of the following is a statement about the climate of Hong Kong? (Select all that apply)
a) The average high temperature last week was 15°C.
b) The average high temperature for February is 19°C.
c) The wind is from Northeast now.
d) It is currently partly cloudy.
e) It will probably be cloudy tomorrow.
f) Typhoon often comes during summer and fall.
24). Which of the following events might cool the earth’s surface? (Select all that apply)
a) Increased black carbon emissions
b) Decreased output from the sun
c) Major volcanic eruption
d) Lowering the earth’s albedo
e) Inject CO2 over the Arctic
f) Inject huge amounts of sea spray aerosols over the tropical ocean
25). Which of the following changes, if they occurred by themselves, would decrease earth’s albedo on average? (Select all that apply)
a) The north polar ice cap expands to cover most of United States
b) The Arctic sea ice melts completely, exposing ocean below
c) Make the Sahara desert covered by trees
d) The earth's cloud cover doubles
26). Which of the following is an example of climate feedback? (Select all that apply)
a) Change in strength of the sun
b) Volcanic eruption that block out the sun
c) Change in water vapor abundance due to global warming
d) Change in cloud cover in a warming climate
e) Changes in greenhouse gas concentration due to anthropogenic emissions
f) Changes in sulfate aerosol concentration due to anthropogenic emissions
27). On average, about _____ of the sunlight that reaches our planet gets reflected or scattered back to space by clouds, dust or Earth’s surface; about _____ is absorbed in the atmosphere, mainly by clouds and water vapor; almost _____ get absorbed by Earth’s surface (land, forest, pavement, ocean, and the rest).
a) 70%; 20%; 10%
b) 30%; 0%; 70%
c) 30%; 20%; 50%
d) 70%; 0%; 30%
28). The deposition of dust onto the snow and ice would result in what type of forcing?
a) Positive longwave forcing;
b) Positive shortwave forcing
c) Negative longwave forcing
d) Negative shortwave forcing
29). Which of the following was the cause of the most recent ice age?
a) Aerosol releases from volcanic eruptions
b) Changes in the Earth's orbit
c) Reduced volcanic activity leading to lower releases of carbon dioxide
d) Increased uptake of carbon dioxide by plant growth
30). What climate factor associated with global warming might increase crop yields? (Select all apply)
a) A decrease in radiation come from the sun
b) An increase of tropospheric ozone
c) Increased hurricane damage in equatorial regions
d) Increased atmospheric CO2
2. (9 points) Radiative balance and feedbacks
1) (6 points) In another star system, there are two suns with temperatures of 6012K and 5890K respectively, and radii of 8×105 and 2×106 km, and 6.82×108 km and 9.2×108 km away from Planet A. The albedo of planet A is 0.25, what is the effective temperatures of A, assuming energy balance and no atmosphere or light interference?
2) (3 points) If planet A’s atmosphere consists of O3, CH4 and CO2, which make A’s surface temperature to be 783K. On A’s surface, what is the ratio of longwave energy from the atmosphere over the total energy emitted by the A surface?
3. (14 points) Sedimentary deposits in rocks show that liquid water was present on Earth as early as 3.8 billion years ago, when solar radiation intensity was only 70% of today’s value. Consider the simple greenhouse model described in this course where the atmosphere is represented as a thin layer transparent to solar radiation and absorbing a fraction f of terrestrial radiation. Assume throughout this problem a constant planetary albedo A = 0.29 for the Earth. Today’s solar constant is Fs=1360 W m-2. The Stefan- Boltzmann constant σ = 5.67×10-8 W m-2 K-4.
1) (4 points) If the greenhouse effect 3.8 billion years ago were f = 0.96, what would be the surface temperature of the Earth? Would liquid water be present?
2) (2 points) What if the atmospheric layer absorbs 75% of terrestrial radiation, would liquid water still be present?
3) (5 points) We can modify our model to produce a warmer surface temperature by representing the atmosphere as two superimposed layers, both transparent to solar radiation and both absorbing 100% of terrestrial and atmospheric radiation. Calculate the resulting surface temperature.
4) (3 points) It has been proposed that the strong greenhouse effect in the early Earth could have resulted from accumulation in the atmosphere of CO2 emitted by volcanoes. Imagine an Earth initially covered by ice. Explain how volcanic CO2 would accumulate in the atmosphere under such conditions, eventually thawing the Earth.
4. (15 points) Cycling of CO2
1) (4 points) Consider the following global cycle of carbon between the atmosphere, the biosphere, the soil, the ocean, and the sediment for the pre-industrial times. Reservoirs are in units of Giga tons (Gt) C (1 Gt = 1×1015 g) and flows are in units of Gt C yr-1. Calculate the lifetime of CO2 in the atmosphere, the terrestrial (biosphere+soil) system, and the entire ocean (surface+intermediate+deep). Which is a more permanent reservoir for sequestering atmospheric CO2: the terrestrial or the entire ocean system? Why?
2) (6 points) Assume one human exhales about 1 kg of carbon dioxide per day. Please calculate the total amount of CO2 from human breathing globally in 2022, with a world population of 8 billion in 2022. How is this compared to the amount of CO2 emitted from fossil fuel combustion (34 billion tons) in 2022? A famous politician suggested sarcastically that “we all quit breathing” to reduce the source of CO2 to the atmosphere. Would that work? Briefly explain.
3) (5 points) Upwelling of deep ocean water supplies high concentrations of nutrients such as nitrogen to the surface ocean. What is the effect of this upwelling on atmospheric CO2?
5. (12 points) Projection of climate change and Mitigation
You want to predict how the level of atmospheric methane might evolve over the next 40 years. Consider two emissions scenarios: RCP4.5 and RCP8.5. For each scenario, compute and plot the projected atmospheric abundance of methane (ppb) versus time (y) for years 2021-2061. Compare the results of the two scenarios. Assume throughout that period atmospheric methane decays by a first-order process with a lifetime of τ = 1/k = 12.4 yr. Assume methane abundance was 1886 ppb at 2021. There are roughly 1.78×1020 moles of air in the atmosphere. The molar mass of methane is 16 g/mol. Your answer should contain the method of computation as well as key figures/data.
1) (5 points) RCP4.5 Assume that the total emissions are the sum of natural emissions, En = 166 Tg CH4 y-1, plus anthropogenic emissions, Ea. The anthropogenic emissions are constant at 332 Tg CH4 per year. You can solve it numerically or analytically.
2) (4 points) RCP8.5 The estimated emission from 2021-2061 has been given in the table below. Please solve it numerically. (Note that 1Mt = 1Tg = 1012g)
3) (3 points) Explain with examples how we can control methane emissions.
YEARS
Mt CH4/yr
6. (5 points) Explain inversion layer life cycle in 5 steps, what is causing the change, and what it will affect.
7. (10 points)
1) During heating water, bubbles first show up at the bottom and get smaller to the top. After water boils, the bubbles also show up at the bottom but get larger to the top. Explain what is inside bubbles before and after water boiling respectively.
2) Explain the meaning of PH2O,SAT when T = 373K and calculate boiling point when temperature is 82°C.
8. (20 points) Responses to climate change
1) (5 points) What is IPCC? What its task and role in climate change management?
2) (5 points) Explain the roles of oceans in determining global and regional climate.
3) (5 points) Describe how climate warming can negatively affect the fishery industry.
4) (5 points) Describe the arguments for “common but differentiated responsibility” in reducing greenhouse gases emissions by developed and developing countries.
