×

×

UH / Geology / GEOL 1302 / What is the formula for quantifying feedback?

# What is the formula for quantifying feedback? Description

##### Description: Covers most of Chapters 7 and 8 and a little bit from Chapter 6
7 Pages 60 Views 5 Unlocks
Reviews

The third exam of GEOL1302: Introduction to Climate Change

## What is the formula for quantifying feedback?

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

(1−g)

(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.

## What is the opposite of el nino?

(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?

(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

## What are the primary factors that control climate?

(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

(d) The

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)

(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).

(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.

(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.

(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.

(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

(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.

(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.

(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).