Climate Change Study Guide Key

Climate Change Study Guide KEY DO NOT WRITE ON THIS PAGE Use this key to check your answers on your study guide. 1. Of the solar radiation that reaches the Earth, how much is deflected (by the atmosphere)? 25% How much is absorbed right away by the atmosphere? 20% How much reaches the surface? 50% 2. What happens to the radiation that reaches the surface? It is absorbed, which heats the surface. It is then radiated out as infrared energy (heat). 3. What is the main cause of the atmosphere heating up? The infrared energy that is radiated out from the surface is absorbed and spread by the gases in the atmosphere. 4. Which gasses are considered to be “greenhouse gasses”? Carbon dioxide, methane, water vapor (These occur naturally.) 5. What is the main effect of the “Greenhouse Effect”? It keeps the earth at a good (warm) temperature for living things 6. What is Earth’s average temperature? 59°°F or 15°°C 7. Our notes state that “growth patterns visible in tree rings tell scientists what the temperature and precipitation were in a specific area”. How do they do that? (What does a thin tree ring tell scientists? What do thick rings mean?) Trees grow one ring a year. If it is a good year (wet, warm), the ring is thick. If it is a bad growing season (dry, cold), the ring is thin. Scientists look at the pattern of thick/thin rings to see what the climate was over time. 8. If scientists find fossils and different types of pollen in the ground, HOW does that help scientists understand what climate had been in that area in the past? They tell scientists what plants/animals used to live in an area. Because plants/animals need certain conditions to survive, scientists can then infer what the climate/conditions must have been like at the time. 9. What information do ice core samples tell scientists about climates in the past? Ice core samples tell scientists about the temperature, precipitation, CO2 levels, and whether there were volcanic eruptions or dust storms during a time period. 10. How far back do ice core samples go in time? ~300,000 years 11. How are tree core samples, soil samples that contain pollen, and ice core samples similar? All three types of evidence have layers that help scientists understand climate. Another similarity is that different samples can be pieced together to create a larger sample set of data that goes farther back in time. 12. Give examples written records that tell scientists about past climates: Artwork, stories, records like those kept by kings/rulers about festivals or payments, ships records, etc. Learning Goal 3: Climate Change (Page 50-51) 13. Describe what Earth’s “normal” climate pattern has been in the past: Earth’s climate normally alternates between warm periods and ice ages 14. Describe what Earth was like during the last Ice Age (or “Glacial Episode”) and tell when it ended? Large areas (30% of Earth’s surface) were covered by ice sheets called glaciers. Sea level was lower. Ended about 10,500 years ago. 15. Describe each of the following possible causes of climate change AND tell how each may influence Earth’s temperature: - Changes in solar energy: The Sun gives off more/less energy over an 11-year cycle. More sun spots (areas of cooler temperatures on the Sun) = more energy and higher temperatures on Earth. Less energy = less spots = less heat = cooler. - Eccentricity: Earth’s orbital path gets more/less oval over time, so Earth is sometimes closer/farther from the Sun. (Closer = warmer) - Precession: Earth tends to wobble on its orbital path. This also effect’s the distance Earth is from the Sun. - Changes in the tilt of Earth’s axis: Earth’s axis changes its angle over time so that it is more/less “tipped over”. This impacts how much energy Earth’s polar regions receives, which impacts temperature. Volcanic eruptions: Eruptions fill the atmosphere with particles that can block the sun and lead to lower temperatures. - Human Activities: burning fossil fuels (like oil and natural gas, such as when we drive our cars) and burning forests/wood releases greenhouse gasses into the atmosphere. Scientists believe this will increase Earth’s temperature BECAUSE these gasses are known to trap and spread heat in the atmosphere. 16. Draw a diagram that shows eccentricity, precession, and how Earth’s axis’ angle changes over time. Label the diagram. NOTE: Also review the possible impact of climate change.