1 Homework: CSE548 Global Climate Change and Society Response (Due on 11 March 2022, Friday) Please write down your answers clearly and BOX the final results. For 5A, you may use MATLAB or Excel to compute the abundances. 1. (30 points) Multiple choice 1). In the last 130 years, the Earth has warmed approximately: a) 0.1 °C b) 10 °C c) 0.8 °C d) 8 °C 2). Which contributes the most to sea level rise so far? a) Mountain glaciers b) Thermal expansion c) Ice shelves d) Ice sheets 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) Shortwave; longwave b) Microwave; longwave c) Ultraviolet; shortwave d) Longwave; shortwave 5). If more solar radiation is reflected back to space, it means the Earth’s albedo has a) Decreased b) Increased 6). If the energy leaving the Earth (Eout) is greater 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) stay the same; decrease b) stay the same; increase c) decrease; decrease 2 d) decrease; 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) 30% higher (410 ppm) c) 50% lower (150 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) Negative; positive b) Positive; negative c) Positive; positive d) Negative; negative 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) Clouds d) Water vapor e) Pinatubo volcanic eruption 12). Emitting black carbon into the atmosphere is _____ aerosol effect and is _____ on climate. a) direct; negative forcing b) direct; positive 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 3 14). 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 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) Heat waves generally bring thunderstorms and heavy precipitation that cause floods d) The sunny and stagnant conditions during heat waves cause high concentration of air pollutants and particles 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 reflect shortwave from the surface. d) Clouds absorb longwave emitted from the surface and radiate it back to the surface. 18). Which of the following are examples of weather events? (select all that apply) a) Tornado touching down in Joplin, Missouri b) Arctic sea ice thickness reducing by 50% in the last 30 years c) Drying of Lake Chad d) 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) 4 f) Hydrogen (H2) g) Tropospheric ozone 21). What is the most abundant greenhouse gas in the atmosphere? a) CO2 b) Water vapor c) N2O d) CFCs 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 wind is from Northeast now. c) The average high temperature for February is 19°C. 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 huge amounts of sea spray aerosols over the tropical ocean f) Inject CO2 over the Arctic 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 5 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 is a result of Arctic sea ice melting? (select all that apply) a) Releases CH4 into the atmosphere b) Increase of sea level c) Decrease of Earth’s albedo d) New shipping routes in the Arctic e) Stratospheric ozone hole 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) Mercury and Venus are 5.79×107 km and 1.08×108 km away from the Sun, respectively. The albedo of Mercury and Venus are 0.12 and 0.75, respectively. What are the effective temperatures of Mercury and Venus assuming energy balance and no atmosphere? Assume the temperature of the Sun is 5778 K and the radius of the Sun is 7×105 km. 6 2) (3 points) Mercury has virtually no atmosphere while Venus’ atmosphere consists mainly of CO2 (96.5%). The greenhouse effect makes Venus’ surface temperature to be 735 K. Is the Venus’ surface temperature higher or lower than the Mercury’s surface temperature? On Venus’ surface, what is the ratio of longwave energy from the atmosphere over the total (shortwave + longwave) energy absorbed? 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 = 0.3 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 the same as today (f = 0.77), what would be the surface temperature of the Earth? Would liquid water be present? 2) (2 points) Current thinking is that a stronger greenhouse effect offset the weaker Sun. Let us try to simulate this stronger greenhouse effect by keeping our 1-layer model for the atmosphere but assuming that the atmospheric layer absorbs 100% of terrestrial radiation. Calculate the resulting surface temperature. 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? 7 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 2021, with a world population of 7.9 billion in 2021. How is this compared to the amount of CO2 emitted from fossil fuel combustion (36.4 billion tons) in 2021? 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. 8 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 2021 426 2022 432 2023 439 2024 445 2025 452 2026 458 2027 465 2028 471 2029 478 2030 484 2031 494 2032 503 2033 512 2034 521 2035 531 2036 540 2037 549 2038 559 2039 568 2040 577 2041 587 2042 597 2043 607 2044 617 2045 627 2046 637 2047 647 2048 657 2049 667 2050 677 2051 684 2052 690 9 2053 697 2054 704 2055 711 2056 718 2057 725 2058 732 2059 738 2060 745 2061 749 6. (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.
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