Sp21_ClimateActivity_Pt2+3

Plenge Sp2021 Climate Modeling Name Poojha Palle Learning objectives: Part 2  Compare current CO2 concentrations and rates of change with historical CO2 data, and current temperatures and rates of change with historical data  Define greenhouse gases, give examples of greenhouse gases and describe how they change Earth’s energy budget. Part 2A. Paleoclimate data Use the information in the lectures and on this website to help you with the following questions: https://carbonconnections.bscs.org/unit-1/1.2-carbon-from-the-past/ 1. Explain how geoscientists can (a) obtain gas bubbles and (b) determine relative age of the gas bubbles using ice cores. Geoscientists obtain gas bubbles by drilling a core in ice sheets. The deeper they drill, the older the ice is, and with these old ice samples are samples of old air. In this way, scientists can measure CO 2 content in these bubbles from different depths. -------------------------------------------------------------------------------------------------------------------------------------------------- Use the graph (also found on the website) to answer the following questions. The 0 on the x-axis represents modern times, which means you travelling back in time as you travel to the right along the x-axis. 2. What is the highest CO2 concentration measured in Antarctic ice? When was it measured? Around 300 ppm, which was around 360,000 years ago. 3. The graph appears cyclic; that is, atmospheric CO2 cycles from a relatively high to a relatively low concentration over time. Approximately how many years pass between peaks in CO2 concentration? Around 125,000 years. Use the graph to answer the following question. 4. Are current CO2 and temperature data correlating the same way they did in the past? (select one) a. Yes, CO2 and temperature show the same trend today that they have in the past. b. No, the temperature is lower than it should be given historical data and current CO2 levels 1

c. No, the temperature is higher than it should be given historical data and current CO2 levels ------------------------------------------------------------------------------------------------------------------------------------------------ Part 2B. Greenhouse Gases as Climate Forcings Use the information in the lectures and on this website to help you with the following questions: https://carbonconnections.bscs.org/unit- 1/1.3-carbon-forcing/ This graph shows an example of a forcing and response in a seasonal climate. The Solar Radiation graph shows solar radiation coming to Denver, Colorado (green curve). The graph also shows average temperatures by day. 5. What is the forcing in this graph? a. Solar radiation b. Time c. Temperature 6. What is the response shown in this graph? a. Solar radiation b. Time c. Temperature 7. What is the lag time in this graph? a. 1 day b. 1 week c. 1 month d. 1 year ------------------------------------------------------------------------------------------------------------------------------------------------ Now let’s talk about CO2 and temperature again. 8. Which of the following is NOT an example of a greenhouse gas? a. N2O (nitrous oxide) c. CH4 (methane) b. H2O (water vapor) d. SOx (sulfur oxide compounds) 9. Which greenhouse gas is responsible for about 75% of the warming on Earth? a. CO2 (carbon dioxide) c. CH4 (methane) b. H2O (water vapor) d. SOx (sulfur oxide compounds) 10. Why are scientists so worried about CO2’s impact on temperature? a. CO2 is the most abundant greenhouse gas b. CO2 cannot flux out of the atmosphere as quickly as being added by humans c. CO2 can easily escape from the atmosphere as it dissolves in rainwater d. Scientists are not worried about CO2 having an impact on temperature Watch this video and use the information you learn to help you answer the next question. https://www.youtube.com/watch?v=UXgDrr6qiUk&t= 2

-------------------------------------------------------------------------------------------------------------------------------------------------- Learning objectives: Part 3  Describe how scientists use models to predict patterns in future climate, including the types of data included in the model and how scientists can test the validity of the model Part 3. Climate Models 1. Use the information in the lectures and watch this video to help you with this question: https://www.youtube.com/watch?v=JRayIgKublg How do scientists get the most reliable measurement of Earth’s overall temperature? Models – scientists characterize a system by identifying processes that govern its evolution; these processes are represented by equations. Models capture the “essence” of how our system works (the world’s system) o 1970 climate model simulated how changes in atmosphere caused average temperature to change over time o Found natural forcings oscillated over long periods of time but human forcings from GHG emissions are steadily increasing Most reliable form of temperature came from weather stations around the world NASA Glory mission will measure solar irradiance and atmospheric aerosols to fill in gaps in climate models -------------------------------------------------------------------------------------------------------------------------------------------------- For the rest of the questions in this section, you’ll be using 2 websites: You’ll want to keep both open in different windows/tabs. The first is informational: https://carbonconnections.bscs.org/unit-3/3.2-testing-forcings The second is a climate model. Please read the information below before you get started so that you understand what you’re doing with the climate mode. https://ecm.coloradocollege.edu/interactive The top graph has three lines, each a different color: - the black line represents the observed temperature anomaly, - the green line is the “best fit model”—Scientists ran tests making each forcing more/less important to figure out controls on Earth’s temperature until they were able to explain 83.9% of the variance. - the red line is the fit of the model based on your manipulation of the amplitudes of the forcings. The amplitude you give each forcing changes the relative importance of each forcing to controlling Earth’s temperature. More explanation on amplitudes:  If anthropogenic CO2 is warming the temperature, but simultaneous starting a negative feedback loop, it may be difficult to determine how much the addition [of each tonne of CO2] will actually change global temperatures.  Scientists measure forcings & temperatures in the past and determine what % of the temperature change can be explained by each forcing. The better they replicate past data, the better estimate they predict future changes.  This model includes 4 different forcings that you can manipulate. The questions in the next section will discuss each of the forcings included. -------------------------------------------------------------------------------------------------------------------------------------------------- El Niño/La Niña 4

On the model, set all forcings except “El Niño” to zero using the slide bars. Adjust the amplitude of the El Niño forcing with the slide bar. 2. Briefly define what an El Niño event is, and why it affects global climate. Period of high sea surface temperatures (SSTs) in the Pacific Ocean along the equator. Called El Nino cause occurs around Christmas. When an event occurs, surface winds change back towards the continent, which reduces upwelling of nutrient-rich waters of the photic zone (upper layer of ocean where photosynthesis occurs). It affects global climate because air above the oceans is heated by this warm water. This can affect global rain patterns too. 3. Which of the following is true regarding El Niño and La Niña events? a. El Niño events are negative forcings, and La Niña events are negative forcings b. El Niño events are positive forcings, and La Niña events are negative forcings c. El Niño are negative forcings, and La Niña events are positive forcings d. El Niño are positive forcings, and La Niña events are positive forcings 4. What is the typical lag time between El Niño or La Niña events and global climate change? a. 5-6 weeks b. 5-6 years c. 5-6 monthsd. 5-6 decades 5. Manipulate the slide bar for El Niño while all other forcings remain at zero. What is the highest value you can get for the red line (read the “fit index” on the right side of the graph)? 0.01 -------------------------------------------------------------------------------------------------------------------------------------------------- Volcanic Forcings On the model, set all forcings except “Volcanic” to zero using the slide bars. Adjust the amplitude of the volcanic forcing with the slide bar. 6. Briefly explain how and why volcanic eruptions affect climate. Erupting volcanoes eject aerosols in the air, which are small particulates that include droplets of liquid or fine pieces of dust. Aerosols, when ejected into the stratosphere, reflect some of the Sun’s energy back into space. This results in global temperature decrease as there is less radiation being absorbed by Earth’s atmosphere. 7. Which eruption would contribute the most significant negative forcing on Earth’s climate? (choose one) a. An eruption in which aerosols remain in the troposphere (do not enter the stratosphere) b. An eruption in which aerosols reach the stratosphere c. An eruption of magma only, with very few particulates . 8. The early 1980 saw two large volcanic eruptions: Mount St. Helens in Washington Sate (May 1980) and El Chichón in southern Mexico (March-April 1982). It takes volcanic aerosols 4-8 months to spread in 5

Anthropogenic (man-made) forcings On the model, set “El Niño, Volcanic, and Solar” to 0. Set “anthropogenic” to 1 using the slide bars. 14. How does the fit of this model compare to observed data between 1979 and 2018? (choose one) a. The red line model overlaps with the observed data, but is the wrong shape b. The red line model shows the general shape of the observed data, but is offset (lower) c. The red line model shows the general shape of the observed data, but is offset (higher) d. The red line model shows the general shape of the observed data, and overlaps a significant portion of the data 15. What is the highest value you can get for the red line (read the “fit index” on the right side of the graph) ? 0.518 16. Which statement best describes anthropogenic forcings over time? a. Anthropogenic forcings explain about 0.5% of the variation observed in global temperature since 1979. b. Anthropogenic forcings have caused a net increase in Earth’s temperature since 1979. c. Anthropogenic forcings have caused a net decrease in Earth’s temperature since 1979. d. Anthropogenic forcings are cyclic in nature 7