The third exam of GEOL1302: Introduction to Climate Change
Note: All of the “Please choose incorrect description” questions contain correct answers in bold from lecture notes so study and memorize them as much as you can before encountering the actual incorrect description on the actual exam.
1. What is the equation for quantifying feedbacks?
(a) (b) (c) (d)
∆ T f=∆Ti
2. Please choose incorrect description.
(a) From question 1, if g=0, then there is no feedback and the final temperature change is equal to the initial temperature change. (b) From question 1, if g is between 0 and 1, then ∆ T f is larger than ∆ Ti , meaning the feedback is positive.
(c) From question 1, if g is less than 0, then ∆ T f is less than ∆ Ti , meaning the feedback is negative. Don't forget about the age old question of What is dominant and dominated strategy?
3. Please choose incorrect description.
(a) Total feedback parameter g for our climate can be expressed as a sum of feedback parameters from the individual feedbacks:
g = gia + gwv+ gcloud+ glr
where gia is the ice–albedo feedback, gwv is the water-vapor feedback, gcloud is the cloud feedback, and glr is the lapse-rate feedback (we consider here only the fast feedbacks). (b) water-vapor feedback = 0.6
(c) ice –albedo feedback = 0.1
(d) lapse rate feedback = − 0.3
4. Please choose incorrect description.
(a) Summing these individual feedbacks, we get a total feedback parameter for our climate of g = 0.4 to 0.7
(b) Feedbacks amplify the warming from that due directly to greenhouse gases and other radiative forcings.
(c) For this doubling of carbon dioxide, the initial warming ΔTi is 1.2°C. Using the feedback strengths implies a range of final temperature ΔTf = 2 to 4.5 °C.
(d) Doubled carbon dioxide corresponds to a radiative forcing (RF) of roughly 4 W/m^2.
5. What is the climate sensitivity (the sensitivity as the warming per unit of radiative forcing)? (a) (b) (c) (d) If you want to learn more check out What if calf wont drink?
The climate sensitivity 0.5 – 1.1 °C/ (W/m^2), with a best estimate of 0.75 °C/ (W/m^2).
6. Please choose the incorrect description.
(a) We have only considered fast feedbacks in our calculation of the climate sensitivity. This is probably appropriate for climate change over the next century.
(b) Over the next millennium and beyond, the contribution of slow feedbacks can become important. These feedbacks are mainly positive, so the climate sensitivity may be significantly higher when we consider such longer periods.
(c) A radiative forcing is an imposed change on the energy balance of the Earth; in response, the Earth changes its temperature so that energy balance is reestablished.
(d) Summing all changes, we get a new radiative forcing over the past 250 years of +1.6 W/m^2. We also discuss several other topics like What causes waves to form?
7. Please choose the incorrect description.
(a) Earth’s continents are moving slowly, but over tens of millions of years, this movement, also referred to as tectonic motion, substantially alters the arrangement of the continents across the Earth’s surface. (b) The location of continents determines whether ice sheets form. (c) Ice sheets form because of cold summer temperatures. If snow that falls during the winter does not melt during the following summer. (d) Land at low latitudes is the most favorable location for cold summers (and winter snow). We also discuss several other topics like Why are females more careful about mating?
8. Please choose the incorrect description.
(a) The loss of an ice sheet will warm the climate.
(b) If Antarctica moved toward the equator over the next 100 million years, loss of the Antarctica ice sheet would be likely, thus leading to significant warming.
(c) The location of the continents determines the ocean circulation. (d) The oceans carry huge amounts of heat from the tropics to the high latitudes, so changing ocean circulation can change the temperatures of the tropics and Polar Regions.
9. Please choose the incorrect description.
(a) Movement of the continents can change the pattern of rainfall and expose new rock to the atmosphere, which changes the locations and rate of chemical weathering – and therefore the amount of carbon dioxide in the atmosphere. We also discuss several other topics like What is the difference between the core promoter and the regulatory promoter?
(b) 40 million years ago the Indian subcontinent collide with the Asian continent, forming the Himalayas and the adjacent Tibetan Plateau.
(c) Changing wind patterns brought heavy rainfall onto the vast expanse of newly exposed rock in these features, and the resultant chemical weathering drew down atmospheric carbon dioxide over a period of tens of millions of years.
(d) The movement of the continents is responsible for the rapid warming of the past few decades
10. Please choose the incorrect description.
(a) If the Sun brightens, the climate will warm. We might therefore wonder if the recent warming of the climate can be explained by an increase in the output of the Sun.
(b) The Sun’s output varies on many time scales. Over the Sun’s 5-billion year life is has slowly gotten 30%.
(c) Since the late 1970, instruments on satellites have been measuring the solar constant, over this period, the most significant observed variation is an 11year cycle, by which total solar energy output varies approximately 0.1 percent. If you want to learn more check out What is not a type of branded content?
(d) The climate does not respond to these 11-year variations because of the enormous thermal inertia of the oceans
11. Please choose the incorrect description.
(a) The rapid warming of the past few decades is not caused by a brightening of the Sun.
(b) The Sun has brightened over the past few hundred years and this can potentially explain at least some of the gradual warming of the 18th, 19th and early 20th centuries.
(c) This has led to a positive radiative forcing with a magnitude of approximately +0.12 W/m2, which is minor compared to radiative forcing from greenhouse gases.
(d) If the Earth moved closer to the Sun, then the solar constant would increase even if the brightness of the Sun did not change.
12. Please choose the incorrect description.
(a) Over the course of 100,000 years or so, as the orbit becomes more eccentric, the average Earth-Sun distance increases and the average amount of solar energy falling on the Earth decreases. (b) For the Earth’s orbit, the change in eccentricity causes the annual average solar constant to vary by approximately 0.5 W/m^2. This change in the solar constant will lead to changes in the Earth’s climate.
(c) Today, the Earth is closest to the Sun during July, when it is wintertime in the northern hemisphere.
(d) In 11,500 years, the Earth will be closest during July, and in 23,000 years it will again be January.
13. Please choose the incorrect description.
(a) Changing the date of closest approach to the Sun or the tilt of the Earth does not change the Earth–Sun distance, so it does not change the solar constant.
(b) Increasing the tilt of the planet increases the amount of sunlight hitting the Polar Regions and decreases the amount hitting the tropics, which alters the climate.
(c) Orbital variations regulate how sunlight is distributed over the planet, so they play a role in regulating these temperatures.
(d) Changes in the output of the Sun or in the Earth’s orbit are examples of forced variability.
14. Please choose the incorrect description.
(a) El Nino events, which make up the warm phase of ENSO, occur every few years and last a year or so.
(b) El Nino’s opposite is La Niña.
(c) During El Nino events, the Earth warms several tenths of a degree Celsius.
(d) During the PETM, an enormous release of either carbon dioxide or methane.
15. Feedbacks react to initial changes in surface temperature and amplify or ameliorate them. Feedbacks can be a cause of climate change? (hint, please refer to question 3 of Chapter 7).
(a) Yes (b) No
Feedbacks do not initiate climate change, but forcings do
16. What is not the primary factors that control our climate? (a) The composition of our atmosphere (e.g., the amount of greenhouse gases in it)
(b) The solar constant
(c) The albedo
Note: the first three of the answer choices are true statements from lecture notes. Therefore, answer which of the statement is incorrect on the actual exam
17. Please choose the incorrect description.
(a) The most important changes over the next century are expected to be in the composition of the atmosphere.
(b) Predicting future climate comes down to predicting the amount of greenhouse gas in our atmosphere.
(c) Potential future paths of greenhouse-gas emissions are known as emissions scenarios. These scenarios form the backbone of our “predictions” of climate change over the coming century (d) The total values of goods and services produced by an economy is known as the gross domestic product, abbreviated GDP
18. Please choose the incorrect description.
(a) The total emission by a society are basically determined by that society’s GDP. If the GDP doubles, then we expect emissions to double, as long as everything else remains the same. (b) Strong evidence of the link between GDP and emissions can be seen during recessions. During the most recent recession (2008 to present) CO2 emissions from US decreased significantly. (c) The total control GHG emission (I) from a society can be described by the following simple equation:
I = P * A * T
where: P = Population (# people)
A = Affluence ($ per person)
T = GHG Intensity (CO2 emissions per $)
(d) GDP scales with population.
19. Please choose the incorrect description.
(a) Every person in a society consumes goods and services, so if the population doubles (and everything else remains the same), then total GDP should also double.
(b) GDP (and GHG emissions) should also scale with affluence ($ per person)
(c) Greenhouse-gas-intensity is known as the Technology term (T) is a measure of how much greenhouse gas is emitted to the atmosphere for every dollar of consumption.
(d) The greenhouse-gas-intensity term T can be broken into two terms: T = EI * CI
where: EI is energy intensity (joule of energy per $) CI is carbon intensity (emitted CO2 per joule of energy)
20. Please choose incorrect description.
(a) Different economic activities take different amounts of energy to generate one dollar of economic output, so it is dependent on the mix of economic activities in an economy.
(b) Industrial manufacturing has a higher energy intensity than do white collar service-oriented activities.
(c) Energy intensity of an economy is the efficiency with which the economy uses energy.
(d) The trade-off is that better technology is often more expensive. LED light bulbs, for example, have higher upfront costs than incandescent bulbs (even though the long-term cost of operation is lower).
21. Please choose incorrect description.
(a) Among fossil fuels, combustion of natural gas produces the least amount of carbon dioxide per joule of energy generated. Thus, it has the
lowest carbon intensity, which is one of the reasons it is often considered to be the “greenest” of the fossil fuels.
(b) Oil produces more carbon dioxide per joule than methane, so it has a higher carbon intensity.
(c) The highest carbon-intensity fossil fuel is coal – it produces twice the carbon dioxide per joule as methane.
(d) Overall, the carbon intensity of a society reflects the mix of technologies used to generate energy.
22. Please choose incorrect description.
(a) I = P*A*T, the product of PAT is in units of CO2 emissions for a given society or economy. As a nation evolves over time, all three of these factors will change as will its GHG emissions. (b) World population has increased by 80% over the past few decades. Today, population is increasing by roughly 200,000 people per day (growth rate of approximately 1% per year).
(c) Most of this growth is occurring in the developing world, where fertility rates remain high.
(d) GDP per person, increased by 80% over the past few decades of the 20th century.
23. Please choose incorrect description.
(a) EI has decreased rapidly as our society has developed more efficient ways to use energy.
(b) Some of this increasing efficiency has been driven by market forces: - energy costs money, a more energy-efficient piece of equipment or process will reduce costs. Because of this economic pressure, everything you buy today is more energy efficient than the comparable 1950s version.
(c) Over the past 50 years, the fraction of the economy based on energy intensive heavy industry and manufacturing has declined, while the fraction based on services has increased.
(d) This reduction in CI occurred as the world shifted from coal to cleaner natural gas.
24. Please choose incorrect description.
(a) Recent increases in population (P) and affluence (A) have tended to increase emissions.
(b) A decrease in green-gas intensity (T) has tended to decrease emissions.
(c) Putting them together, the net change in emissions between 1970 and 2005 was an increase of 75%.
(d) Key factors in determining how fast affluence grows globally: Level of education, Rule of Law, Free Trade, and Access to technology
25. Please choose incorrect description.
(a) Energy intensity has decreased as 2% per year.
(b) Continued reduction in Carbon Intensity possible through expanded use of natural gas to replace oil and coal.
(c) Predicting future population requires predictions of factors: poverty, religious and social views on birth control, rate of education of women, and availability of healthcare
(d) The most well-known set of scenarios come from the IPCC: A1, A2, B1, and B2.
26. Please choose incorrect description.
(a) A1: a world of rapid economic growth, where both rich and poor experience gains in wealth.
(b) B1: A world where both rich and poor experience gains in wealth, but at a slower rate than A1 scenario.
(c) B2: A world of uneven economic growth, with rich getting wealthier but poor remaining poor.
(d) All 4 scenarios assume the world does not work together to address climate change by reducing emissions systematically.
27. Please choose incorrect description.
(a) Climate model simulations suggested by 2100, the Earth will be 1.8-3.6°C warmer the year 2000.
(b) The warming is avoidable, which is why it is often referred to as “committed warming”.
(c) Range of model output using the same emissions scenarios and a large number of different climate models allows us to evaluate uncertainty in prediction from “physics” of climate models.
(d) Range in temperature by 2100 due to different emissions is also a factor of 2 (i.e., 2 to 4°C).
28. Please choose incorrect description.
(a) Approximately 50% of CO2 added to atmosphere is removed within 1 year as C is absorbed by plants on land (25%) and surface water of the ocean (25%).
(b) After a few centuries – equilibrium between atmosphere and deep ocean results in 70% of CO2 emitted in the deep ocean (and 30% of CO2 emitted still in ATM).
(c) Over 1000s of years, CO2 is slowly removed the atmosphere-ocean system by chemical weathering (and stored as?).
(d) CO2 remains relatively high throughout the 1000 years.