The second exam of GEOL1302: Introduction to Climate Change
1. Please choose incorrect description.
(a) The ultimate source of energy for our planet is the Sun, which puts out an amazing 3.8 x 10^26 W (380 trillion trillion W) of power. (b) The Sun emits photons in all directions, so only a small fraction of the photons emitted end up falling on the Earth.
(c) The 1,360 W/m^2 is known as the solar constant for the Earth; it is represented in certain equations by the symbol S.
(d) The solar constant is function of how far the sunlight is delivering at the planet’s orbit.
2. Please choose incorrect description.
(a) The reflectivity of a planet is called the albedo, from the Latin word for “whiteness.”
(b) The albedo of the earth is usually represented by the Greek Letter α (alpha).
(c) The Earth absorbs an average of 238 W/m2 from the Sun, but that does not mean that every square meter of the Earth absorbs this amount. (d) The amount of sunlight received is at maximum if the surface is oriented perpendicular to the incoming beam.
3. Please choose incorrect description.
(a) The tropics are mainly open ocean, which is dark and therefore has a low albedo.
(b) In one-layer model, the Earth’s atmosphere is transparent to visible photons emitted by the Sun (which have wavelengths from 0.3 – 0.8 µm), so these photons speed through the atmosphere and reach the surface.
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(c) In one-layer model, the atmosphere is opaque to infrared photons emitted by the surface (wavelengths from 4 – 20 µm), and so all of these photons are absorbed by the atmosphere.
(d) In one-layer model, the atmosphere also behaves like a blackbody, so it emits photons based on its temperature.
4. Please choose incorrect description.
(a) Mercury is the planet closest to the Sun, yet Venus, twice as far from the Sun as Mercury, has a surface temperature that is approximately 300 K warmer.
(b) The inferred n for Mercury is near zero, suggesting it has almost no greenhouse effect.
(c) The greenhouse effect on Mars is expected to be weaker than that on Earth.
(d) The result of the massive, greenhouse-gas-rich atmosphere is a planet hotter than the inside of your oven on boil – hot enough even to melt lead.
5. What is the right equation for energy in for a planet?
(a) (b) (c) (d)
E¿ = S (1−α)
6. What is the surface area of a sphere with radius r?
(a) (b) (c) (d)
4 π r^2 = 4π (150 million km)^2 = 2.8 x 10^17 km^2 = 2.8 x 10^23 m^2
7. A planet in another solar system has a solar constant S=2000 W/m^2, and the distance between the planet and the star is 100 million km. What is the total power output of the star (in W)? hint: use 4πr^2 * S. If you want to learn more check out What does remain dwells on love and public rituals?
(a) (b) (c) (d)
P = 4πr^2 * S S = 2000 W/m^2 π = 3.14 r = 100,000,000 km = 100,000,000,000 m
100,000,000 km x 1,000 m/1 km = 100,000,000,000 m P = 4(3.14)(100,000,000,000 m)^2(2000 W/m^2) = 2.512 x 10^20 W
8. Alex and Jane argue about why Venus is so much warmer than the Earth. Alex argues that it is because …... Jane argues that it is because ….. Which person is right?
(a) Alex (b) Jane We also discuss several other topics like How is replacement cost calculated?
Venus is twice as far from the Sun as Mercury, has a surface temperature that is approximately 300 K warmer. This result becomes even more puzzling when we realized that, because of its high albedo, the energy in for Venus, S(1 – α )/4 = 200 W/m^2, is more than a factor of 10 smaller than that for Mercury (2,250 W/m^2). It is even less than the energy in for the Earth (238 W/m^2) – yet Venus is approximately 450 K hotter than the Earth. Venus is so much hotter than Earth’s, not because its atmosphere contains so much CO2, but because it is some 30% closer to the sun, and its atmosphere is 90 times denser at surface level than Earth’s. If you want to learn more check out What is our best explanation for the fall of civilizations in the aegean region that was followed by a descent into a centuries-long "dark age"?
9. One argument you hear against mainstream climate science is that adding greenhouse gases to the atmosphere is like painting a window. Eventually, the window is opaque, so that adding another coat of paint does nothing. Is this a good analogy? Don't forget about the age old question of What makes e. coli a good bacteria?
(a) Yes (b) No
The greenhouse gases are like paining a window is not a good analogy. By adding more into the atmosphere, eventually it will become ineffective to our planet. This analogy deflects some of the studies and research that has been done on greenhouse gases.
10. Please choose the incorrect description.
(a) The greenhouse effect occurs because our atmosphere is basically transparent to visible photons but absorbs infrared photons. (b) The abundance of water vapor varies widely from place to place. (c) Water vapor is the most abundant and important greenhouse gas in our atmosphere. Don't forget about the age old question of What is the main function of microfilaments?
(d) Ozone is a final greenhouse gas, which is a molecule made up of three oxygen atoms, so its chemical formula is O3 .
11. What is not among greenhouse gases?
(a) (b) (c) (d)
Diatomic nitrogen, Diatomic oxygen, and argon are not greenhouse gases at all
12. Please choose the incorrect description.
(a) Plants absorb carbon dioxide from the atmosphere and use it to produce more plant material in a process known as photosynthesis: C O2+H2 O + sunlight → C H2 O + O2
(b) The production of a carbohydrate through photosynthesis followed by its consumption during respiration therefore produces no net change in either carbon dioxide or molecular oxygen.
(c) The atmosphere contained approximately 740 gigatonnes of carbon (GtC).
(d) The land biosphere contains 2,000 GtC or so, stored in living plants and animals, and in organic carbon in soils (e.g., decaying leaves).
13. Please choose the incorrect description.
(a) During the northern hemisphere’s fall and winter (October – April), plant material that was produced during the spring and summer decays, releasing carbon back into the atmosphere in the form of carbon dioxide.
(b) Carbon dioxide readily dissolves in water.
(c) Once CO2 has dissolved in water, it is converted to carbonic acid ( H2C O3 ) by means of this reaction: C O2+H2 O → H2 CO3
(d) The mixed layer is well mixed by winds and strong weather events, such as hurricanes.
14. Please choose the incorrect description.
(a) Approximately 100 GtC per year are continuously cycling between the atmosphere and land biosphere as plants absorb carbon dioxide as they grow and then release carbon dioxide when they die. (b) A carbon atom stays in the atmosphere for only four years or so before it is transferred into the land biosphere or ocean.
(c) The turnover time of carbon in the land biosphere is 2,000 GtC divided by 100 GtC/yr = 20 years. This means that a carbon atom in the land biosphere will stay there for approximately 20 years before being transferred into the atmosphere.
(d) The atmosphere exchanges carbon rapidly with the land biosphere and mixed layer, and much more slowly (time scale of centuries) with the deep ocean.
15. Please choose the incorrect description.
(a) Most of the carbon in the world – many millions of gigatons of carbons – is stored in rocks, such as limestone (CaCO3), and this carbon is slowly exchanging with the atmosphere-land biosphere-ocean system. (b) The volcanic emissions of carbon dioxide from the rock reservoir are roughly balanced by a process known as chemical weathering, which removes about an equal amount of carbon from the atmosphere land biosphere-ocean reservoir and transfers it back into rocks. (c) Once in the ocean, the molecules of calcium carbonate are deposited through various mechanisms on the sea floor.
(d) When fossil fuels are burned, the net reaction is similar to the respiration reaction.
16. Please choose the incorrect description.
(a) The chemical properties of an atom are for the most part set by the number of protons, so isotopes tend to have very similar chemical properties.
(b) Carbon-14 is known as radiocarbon because it is radioactive. That means its nucleus is unstable and converts back to nitrogen-14 with a half-life of approximately 6,000 years.
(c) Methane is emitted to the atmosphere from coal mines adds 50 million tons per year.
(d) In the last decade, about two third of the methane emissions are due to human activities, whereas one third is from natural resources.
17. What is the process that transfers carbon from the atmosphere to the land?
There are many processes that transfer carbon from atmosphere to land like photosynthesis, fossil pools, net terrestrial uptake, and net ocean uptake.
18. Of the carbon dioxide humans add to the climate, approximately half is removed within a year. Where does it go?
(a) All go (b) All go into the (c) Half goes into Half goes into the ocean and half goes into the land-biosphere
19. Please choose the incorrect description.
(a) The ocean mixed layer is in contact with the atmosphere, so greenhouse gases intercept some of the energy escaping to space and redirect it back toward the surface. In this way, greenhouse gases both reduce energy out for the planet and increase energy in for the surface, thereby warming the planet.
(b) If we stopped emitting greenhouse gases today, the climate would still experience approximately a half a degree warming over the next few decades.
(c) Radiative forcing is the change in Ein – Eout for the planet as a result of some change imposed on the planet before the temperature of the planet has adjusted in response:
RF = Δ (Ein – Eout) = Δ Ein – Δ Eout
(d) An important source of stratospheric water vapor is the transport of methane into the stratosphere followed by oxidation, which has this net reaction: C H4+2O2 → 2 H2O+¿ C O2
20. Please choose the incorrect description.
(a) Aerosols are particles so small that they do not fall under the force of gravity, but remain suspended in the atmosphere for days or weeks. (b) Sulfate aerosols are highly reflective and reflect incoming solar radiation back to space, so their net effect is to cool the climate. (c) Volcanoes emit enormous amounts of sulfur gas, and energetic eruptions can inject it directly into the stratosphere. (d) A few years after a volcanic eruption into the stratosphere, stratospheric aerosols fall out of the stratosphere and the climate warms back up.
21. Please choose the incorrect description.
(a) Most of dust comes from natural processes, such as dust picked up off the world’s deserts by strong winds.
(b) Approximately 20 % of mineral dust comes from anthropogenic sources – mainly agricultural practices (e.g., harvesting, plowing, overgrazing), changes in surface water features (e.g., drying out of lakes such as the Aral Sea and Lake Owens) and industrial practices (e.g., cement production, transport).
(c) If you add aerosols to a cloud, then you will increase the number of CCN – and therefore the number of cloud droplets making up the cloud.
(d) A cloud containing smaller droplets is more reflective than bigger droplets.
22. Please choose the incorrect descriptions.
(a) Considering all the effects of aerosols on clouds, scientists estimate that the indirect aerosol effect produces a negative radiative forcing of -0.7 W/m^2.
(b) Because aerosols last only a few weeks in the atmosphere before they are removed, aerosols do not have time to become well mixed throughout the atmosphere (which takes a year or so). (c) From a climate perspective, the negative radiative forcing from aerosols offsets 40% or so of the positive radiative forcing that is due to greenhouse gases.
(d) Agricultural land typically has a higher albedo than does the natural landscape, especially if the latter is forest.
23. Please choose the incorrect description.
(a) Summing all the radiative forcings in the period between 1750 and 2005, we get a net radiating forcing of +1.6 W/m^2.
(b) A positive feedback is to amplify an initial warming. (c) The biggest negative feedback is known as lapse-rate feedback. (d) Water vapor, clouds, and the lapse rate respond within a week or in a few years.
24. Which process is related to slow feedback?
(a) (b) (c) (d)
25. Here are fast feedbacks operating in our climate. Please choose the incorrect description. (a) Water vapor: gwv = 0.6
(b) Lapse-rate: glr=−0.3
(c) Ice-albedo: gia=0.1
(d) Cloud: gcloud=0.0−0.3
26. Imaging that we add some carbon dioxide to the atmosphere and the Earth warms by 1◦C. How much warming would there have been if there were no feedback?
(a) (b) (c) (d)
About one third of that value, 0.3°C.
27. In the northern hemisphere, Ein maximizes on June 21, when the sun is most directly overhead. You might therefore expect temperature to be
highest on that day. But for the U.S. Gulf Coast, temperatures do not reach their hottest temperatures …………………... Is it true?
(a) Yes (b) No
This period is called solstice
28. (from problem 27) what makes this occurrence?
(a) Large mass …. (b) Many … (c) Large mass … (d) A lot of …
This is because of tilt of the earth axis of rotation with respect to its orbital path around the sun. The axis of rotations imaginary line drawn straight through earth connecting north pole to south pole. This line is tilted 23.5 degrees from earth’s orbital path around the sun. This mean that the sun does not hit earth evenly at particular latitude above the equator