Can Global Warming Cause Global Cooling? Climate Change in Greenland and the North Atlantic 3 by Betsy Youngman and David Smith

Can Global Warming Cause Global Cooling? Climate Change in Greenland and the North Atlantic 3 By Betsy Youngman and David Smith

Guiding Question Learning Objectives How fast is the Greenland ice sheet Students will be able to: melting, and what are the possible • describe the rate of change of the impacts of that change? Greenland ice sheet and the impacts on the salinity in the North Atlantic Project Duration • explain the possible impact of climate Three to five 45-minute class periods change on the global thermohaline ocean circulation Grade Level • relate ocean currents to terrestrial Grades 8-12+ (ages 13-18) climate classification

Subjects • Environmental Science • Earth Science • Oceanography

Project 3 of Investigating Your World with My World GIS • www.natgeoed.org/MyWorldGIS Copyright 2012 National Geographic Society. Photographs by Betsy Youngman (top left); George F. Mobley (top right); Chuck Tomlin, My Shot (bottom) Mobley (top right); Chuck Tomlin, (top left); George F. Photographs by Betsy Youngman Copyright 2012 National Geographic Society. TEACHER INSTRUCTIONS

Can Global Warming Cause Global Cooling? Climate Change in Greenland and the North Atlantic By Betsy Youngman and David Smith

Connections to National Standards How fast is the Greenland NATIONAL SCIENCE EDUCATION STANDARDS, GRADES 9-12 ice sheet melting, and what • Standard A-1: Abilities necessary to do scientific inquiry are the possible impacts of • Standard F-5: Natural and human-induced hazards • Standard F-6: Science and technology in local, that change? national, and global challenges

NATIONAL GEOGRAPHY STANDARDS • Standard 1: How to Use Maps and Other Geographic Overview Representations, Tools, and Technologies to Acquire, Students use GIS and other media to explore a critical Process, and Report Information From a Spatial area of climate change research: glacial melting and its Perspective potential impact on the ocean currents. In Lesson A, • Standard 14: How Human Actions Modify the Physical students are introduced to the Greenland ice sheet and Environment observe the increase in melting on the ice sheet. Lesson • Standard 18: How to Apply Geography to Interpret the B of the activity introduces students to the great oceanic Present and Plan for the Future conveyor belt and the critical deep-water formation zones that drive this system. Lesson C examines the question: Vocabulary what will happen to climate if the oceanic conveyor belt • glacier, noun—a mass of ice that originates on land, slows? usually having an area larger than one tenth of a square kilometer; many believe that a glacier must show Background some type of movement; others believe that a glacier Evidence shows increased melting of glaciers in can show evidence of past or present movement. The Greenland. The addition of fresh water to the North Greenland ice sheet is a thick glacier that covers most Atlantic threatens to alter the ocean’s salinity in the North of the island of Greenland. Atlantic region. The North Atlantic is also home to a key • glacial mass balance, noun—the difference between the area of the oceanic conveyor belt, where colder, denser accumulation (gain) and ablation (loss) of glacial ice water sinks and initiates the conveyor. Given the role that and snow. A glacier that has negative mass balance is salinity plays in maintaining the oceanic conveyor belt, in retreat, or decline. Usually calculated on an annual a decrease in salinity due to the addition of fresh water basis. (which is less dense) from the melting of the Greenland • salinity, noun—amount of salt dissolved in a liquid; ice sheet threatens to slow or shut down the oceanic saltiness. conveyor belt. If the conveyor shuts down, it will no longer bring warm, ocean waters from the south to areas of Northern Europe. Since the ocean plays an important role in the local climate balance, this could lead to a dramatic drop in local temperatures for Northern Europe.

Can Global Warming Cause Global Cooling? • Teacher Instructions • Page 27 TEACHER INSTRUCTIONS

Teaching Strategies Extending the Learning In this chapter there are three separate GIS lessons; each • Show one of the following the short videos: “NOVA: takes approximately one class period to complete. Science Now—Fastest Glacier” or “Scientific American The lessons are: Frontiers XV: Hot Planet—Cold Comfort.” Both videos • Lesson A: Is Greenland Melting? are available online. Have a discussion about what • Lesson B: Is the Salinity in the North Atlantic students observe in the videos. Changing? • Have students complete research about the present • Lesson C: How are Climate and Ocean Currents trends in the melting of the Greenland Ice Sheet. Some Interlocked? resources are listed below: —NASA Global Climate Change Key Indicators: http:// You will need to allow time for an introduction to the topic climate.nasa.gov/keyIndicators/index.cfm#landIce and a wrap-up discussion. —NSIDC Atlas of the Cyrosphere: Begin with a class discussion of the key question. Include http://nsidc.org/data/atlas/ in the discussion the topics of climate, climate change, —NASA Annual Accumulated Melt over Greenland, and climate change research. Use a globe or map to 1979 through 2009: http://svs.gsfc.nasa.gov/vis/ introduce students to the location of Greenland and the a000000/a003700/a003721/index.html Atlantic Ocean. Remind students that they are working • Learn more about remote sensing and the study with the data that is currently being collected by the of the Cyrosphere on the ICEsat page. scientists. Many scientists around the world are working http://icesat.gsfc.nasa.gov/ together to understand climate change and its possible • Help students learn more about climate change outcomes. Like the scientists, students may have to think research by showing segments from the video, about how the data sets are connected. Climate change “Earth: The Operators Manual”: has many features and fingerprints; in order to see the http://earththeoperatorsmanual.com/for_educators connections one needs to think like a detective! Engage students in the excitement about Greenland’s Additional Resources changing ice sheet. Read recent news and share images • MapMaker 1-page Maps: http://education. of melting glacial ice from the June 2010 National nationalgeographic.com/education/mapping/outline- Geographic Magazine article, “Greenland: Ground Zero for map/?ar_a=1 Global Warming.” The article is linked in the Resources • National Geographic Climate Change Collection: Global section, below. Warming. http://education.nationalgeographic.com/ education/topics/global-warming/?ar_a=1 After the whole-class introduction, have students work in • National Snow and Ice Data Center’s resources for pairs at computers while using My World GIS. Give each educators, scientists and citizens: http://nsidc.org/ pair the Student Instructions, the Answer Sheet, and a • Details of Ice Velocities Around the 2000-meter Traverse in blank outline map of the world. See Resources for a link Greenland: http://nsidc.org/data/parca/data.html#parca-9 to blank maps. • NASA Images and trends of melting ice: Students will use three project files in this chapter: http://www.nasa.gov/externalflash/globaliceviewer/ climate_change_greenland.m3vz • Woods Hole Oceanographic Institute’s in-depth analysis climate_change_oceans.m3vz of the changes in the North Atlantic. climate_change_impacts.m3vz —“A River Runs Through It: Chronicling the Currents of the North Atlantic” http://www.whoi.edu/page. do?pid=12455&tid=282&cid=2557 —Abrupt Climate Change: Should We Be Worried? http://www.whoi.edu/page. do?pid=12455&tid=282&cid=9986

Can Global Warming Cause Global Cooling? • Teacher Instructions • Page 28 TEACHER INSTRUCTIONS

Data Dictionary Additional information about each of the layers used in this project • Greenland AWS Locations: Greenland Automated • Avg River Discharge (m^3/s): River discharge Weather Stations. Located on the Greenland ice shows the amount of fresh water entering the sheet. Source: Konrad Steffen—University of ocean Colorado CIRES • Salinity Research Sites: Oceanographic research • Glacier Velocity Gates: Locations marked with buoys used in salinity, temperature, and current geospatial coordinates. Used in monitoring the velocity research. Credit: Ruth Curry—Woods Hole motion of the ice sheet. Source: Bea Csatho—Ohio Oceanographic Institute State University • Dense Water Formation Sites: Locations where • Greenland ice sheet (km): Ice sheet location and deep ocean currents form due to changes in extent. Credit: National Snow and Ice Data Center salinity and temperature • 1992—2002 Greenland Melting Extents: Summer • Avg Annual Surface Temp and Salinity of Oceans: melting area and extent. These are locations Surface temperature and salinity of the ocean where liquid water can be detected on top of the • Elevation and Sea-floor Bathymetry: Shows ice sheet. Recorded by satellite. Source: Russell elevation of Earth’s surface features Huff—University of Colorado CIRES • Generalized Ocean Conveyor Belt: Thermohaline • Continents: Polygon layer with continental circulation pattern boundaries. Source: ESRI • Global Wind Pattern: Generalized pattern of winds • Buoy Locations: Oceanographic research buoys over oceans used in salinity, temperature, and current velocity • Surface Currents: Generalized pattern of surface research. Source: Bob Dickson—Centre for currents driven by winds over oceans Environment, Fisheries and Aquaculture Science • Climate Classes (Simple): Regions of similar (CEFAS) climate (precipitation and temperature)

Can Global Warming Cause Global Cooling? • Teacher Instructions • Page 29 STUDENT INSTRUCTIONS

Can Global Warming Cause Global Cooling? Climate Change in Greenland and the North Atlantic By Betsy Youngman and David Smith

n this investigation, you will learn how scientists are monitoring the melting of the Greenland ice sheet How fast is the Greenland Iand how the deep ocean currents that form in the North Atlantic drive the great ocean conveyor belt. You ice sheet melting, and what will consider the potential impacts on climate that could are the possible impacts of result from a change in the salinity of the ocean water in this region. that change? Use the student answer sheet to record your answers for this investigation.

Lesson A: Is Greenland Melting? Part I: Observing an Ice Sheet takes a Special Kind of Scientist INTRODUCTION One of the potential impacts of global warming is the melting of the Greenland ice sheet. Scientists have been monitoring the ice sheet for over 100 years using a variety of techniques, including ground-based weather stations. Advances in satellite monitoring in the past 20 years have improved our ability to see changes in large-scale systems such as Greenland’s ice sheet. The combination of evidence of change from many sources of observations, including ground and space-based, has given scientists reason for concern. Climate change has many features and fingerprints; scientists think like detectives! This project includes text and photos from some of the scientists who are studying the ice sheet behavior. Read on to learn more about their work.

1. Launch My World GIS by double- clicking its icon on the Dock (Mac) or Start List (PC).

2. Choose File > Open Project. Navigate to where you have stored Climate_Change_Greenland.m3vz and open the file. It will open displaying Greenland centered in the map.

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3. Click the check box to turn on the following layers: • Greenland AWS Locations (Photo and Movie Links) • Greenland Ice Sheet

4. Create a legend by name for the all of the Greenland weather stations data layers by selecting “name” in the layer’s color pull-down menu.

5. Locate the following stations by clicking the map with your Pointer Tool . Notice that the thickness of the Greenland Ice Sheet layer is also displayed in the legend below the map. • Swiss camp • Summit • CP2 • JAR 1

These stations are a few of the many weather and glacier observing locations that are visited by scientists tracking the behavior and conditions on the ice sheet.

6. Select the Link Tool and locate the Weather Station and camp pictures that are linked to the map. Click the flags to observe them. Use your answer sheet to record what you observe about these stations and the working conditions for scientists.

Noah Malotch is digging himself out of a crevasse. Notice he is not wearing gloves. The ice sheet edges have many such crevasses. Generally, these cracks are not big enough to swallow a person, but you can find yourself stuck up to your waist. (Photo by Jason Box)

Markus Frey (right) and Betsy Youngman work together on an atmospheric chemistry experiment. Summit Station is the location where the ice cores were drilled in 1992. These cores tell us the climate history of the region over the past 110,000 Russell Huff climbs a weather station to set it up. years. Research continues at Summit Station year Koni Steffen looks on. Russell and Koni have been round. studying the changes on the Greenland ice sheet for This picture was taken on a very warm July day in many years. 7.2001. (Photo by Jason Box) (Photo by Jason Box)

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Open the table associated with this Automated Weather TABLE TIPS: You can open an activated layer’s table using the pulldown Station (AWS) location layer. menu “Layer” and selecting “Show Layer Table...” or selecting the “Show Table of Selected Layer” icon . Sort the weather stations by elevation. Sort a field by clicking the field name. Each click will sort the field, The highest station, Summit, is at 3208 meters, ascending descending , and then back to unsorted. or approximately 10,000 feet.

8. Record the elevations of 6 stations (4 listed and 2 of your choice) in the table on the answer sheet; include stations from several elevations and include the station with the highest and lowest elevations.

QUESTION 1: Describe the 6 stations that you choose in the table on your answer sheet. In the comments box, list tools or equipment you would bring to survive there. For example, what clothing would you need?

Station Name Elevation Comments Summit Swiss Camp CP-1 JAR 1

9. With the table of the Layer open and sorted by elevation, click the ID# field for all of the stations that are above 2000 meters. Then, click the Make selection from Rows button. Name your selection above 2000 meters and click OK.

QUESTION 2: How many stations are above 2000 m? Hint: click the data table associated with this layer. What else do you notice about the elevation and spatial distribution of the weather stations? (e.g. North vs. South, etc.)

QUESTION 3: Why might this distribution of stations be scientifically important?

Not all data are collected at camps, in fact most are collected by automated weather stations. The weather stations are maintained on a bi-annual basis by a team of scientists, including those pictured in the links. To maintain the stations the team travels by small plane or snowmobile. At the stations, the scientists also use computers to gather additional data not transmitted by satellite due to bandwidth limitations.

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10. Follow the link to read how automatic weather stations record and transmit data: http://cires.colorado.edu/science/groups/steffen/gcnet/

Automatic Weather Stations (AWS)

As of the 1999 field season, 18 automatic weather stations (AWS) are collecting climate information on Greenland’s ice sheet. Each AWS is equipped with a number of instruments to sample the following: • air temperature, wind speed, wind direction, humidity, pressure • accumulation rate at high temporal resolution to identify and resolve individual storms • surface radiation balance in visible and infrared wavelengths • sensible and latent heat flux fluxes • snowpack conductive heat fluxes Hourly average data are transmitted via a satellite link (GOES or ARGOS) throughout the year. In addition, measurements are stored in solid-state memory. The system is powered with two 100 Ah batteries, charged by a 10 or 20 W solar panel. The satellite data-link is powered by two separate 100 Ah batteries connected to a 20 W solar panel. This setup guarantees continuous data recordings and storage, even in the case of satellite transmission failure. The expected lifetime of the instrumentation is 5 years.

Conditions recorded at these weather stations are used to calculate and validate the melt extent of the Greenland ice sheet. As described in an email from scientist Russell Huff, “they form the truth for much of the climate science on the ice sheet.”

Optional: If your school has a weather station, take a tour of it and compare your weather data to the data collected in Greenland.

QUESTION 4: What month is the peak season for melting in Greenland?

11. Turn off the Greenland Ice Sheet layer and the Greenland AWS locations layer.

Part II. Observing Changes in an Ice Sheet 1. On your Map turn on the Greenland Melting Extents by year. Use the pull-down menu to select the 1992 melt extent layer for your map. It is colored red.

2. Click the open Analysis Window Button and choose Select…By Value. Create a selection of records where 1992 melting is present. Choose Select items from Greenland Melting Extents by year whose 1992 is less than 2 and greater than or equal to 1. The number “1” represents an area that has experienced melting on the ice sheet of Greenland. In the table you will notice that there is only one other choice, –9,999, which means not melting.

3. Repeat this procedure for 2002. You should now have two radio buttons. Choose the 1992 radio button and click inside the table next to the text. It will be highlighted in a blue color.

4. With the selection highlighted, click the table button above the layer list to see the number of areas that melted in 1992: ______out of 22,990

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5. Change the highlighted selection to 2002 and repeat this procedure: ______out of 22,990 How many more areas showed melt in 2002 than in 1992?

QUESTION 5: Record your data in the “Melt Extent Data Chart” on the answer sheet.

6. Turn on the Greenland AWS locations layer again.

7. Return to the analysis window and select the weather stations that crossed the melt extent in both 1992 and then again in 2002. How many were there in 1992? In 2002? Record your data in the “Melt Extent Data Chart” on the answer sheet.

QUESTION 6: What does melting do to an ice sheet?

Glaciers that are covered in snow are highly reflective. The measure of this reflectivity is known as albedo. The most reflective surfaces on Earth are glaciers. The least reflective surfaces are water bodies. One of the results of a glacier melting is that it becomes less reflective and absorbs even more sunlight, thereby increasing the rate of melting. This is known as a positive feedback loop.

8. Turn off the Greenland Melting Extent by year layer Turn off the Greenland AWS Locations (Photo and Movie Links) layer Turn on the Greenland (Melt Extent PDF link) layer Russell Huff of the Cooperative Institute for Research in Environmental Sciences (CIRES) has done the research and created the graph linked to the Greenland layer.

QUESTION 7: Use the Link Tool to open the linked graph and answer the following questions on your answer sheet. • How many years has data been recorded for this graph? • How much has the melt area increased since 1992? • How many square km was the melt in 2002? • What other trends did you notice?

9. Close the link and return to your map.

10. Turn off all layers except Continents.

Part III. Glaciers on the Go 1. Turn on the Glacier Velocity Gates layer and Greenland Ice Sheet layers. In this section we will answer these questions: • How does the increase in melting change the flow of the glaciers? • Why would scientists want to record the velocity of the Greenland glaciers?

Each gate is a section of the ice sheet marked with a GPS point. These “gates,” between which the glacial flow is measured, were set up by scientists from Ohio State University and are monitored by airplane every other year.

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More information about the methods used for this study can be found at the National Snow and Ice Data Center.

2. Click the table icon to open the data table associated with the Greenland Glacier Velocity Gates layer.

QUESTION 8: What is velocity? In what units is it measured?

3. Zoom in on Greenland with the Zoom Tool .

4. Use the Measure tool to check the distance between several successive pairs of “gates.” To make a measurement, click the Measure tool icon to select it (it will turn gray.) Then move to the map where the crosshair cursor can be placed on any gate and clicked once to start measuring. Move to an adjacent gate (a line will draw) and click twice. The distance, in meters, appears on the lower-left information bar of the My World GIS window.

QUESTION 9: Record the average distance between gates in the answer sheet chart.

5. Use the Pointer Tool to click a variety of gates and notice the small arrow on the legend below the map. The gates are all approximately at the same elevation.

QUESTION 10: Record this elevation. From what you know about weather and glaciers, do you think uniform elevation might be important?

6. Turn off the Greenland Ice heet layer.

7. Find the areas of the ice sheet where the average velocity between a set of gates is faster than 80 m/yr.

8. Activate the Glacier Velocity Gates layer.

9. Edit the legend’s appearance by double clicking it. Choose “color by velocity (m/year);” in the Legend Editor you may also want to choose “size by velocity.” Record your findings in table on the answer sheet.

QUESTION 11: Is there any pattern of where the fast moving glaciers are located? How might this be related to weather patterns?

QUESTION 12: If the glaciers in southern Greenland are rapidly thinning, where does this melt water go?

Conclude: Use any remaining time that you have to begin to prepare a short (2 minute) presentation to share with your classmates. Record your observations on your answer sheet and on the printed map that you have. Be sure to answer these questions:

QUESTION 13: What have you found is happening to Greenland? How do you know what you know? • How do scientists observe a glacier? • What instruments/tools do they use? • What is the data telling us about the ice sheet in Greenland?

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Lesson B: Is the Salinity in the North Atlantic Changing? Part I: Getting a Global Perspective of the Ocean Research Process INTRODUCTION Scientists have monitored the currents and conditions in the Atlantic Ocean since Ben Franklin discovered the Gulf Stream in the 1800s. Recently, with the advent of satellites and enhanced buoy systems, scientists have been able to more accurately track the origin and movement of the ocean water. The conditions in the ocean are monitored using a combination of satellite sensing and ocean buoy data recording. There is much international attention directed to the region closest to Greenland, the origin of the dense water that drives thermohaline circulation. (thermo= temperature, haline=salty)

KEY QUESTIONS • What instruments do scientists use to observe the ocean’s temperature and salinity? • What two factors contribute to density of ocean water? • How much has the salinity in the North Atlantic changed?

GETTING STARTED 1. Launch My World GIS by double-clicking its icon on the Dock (Mac) or Start List (PC) and open the Project: Climate_Change_Oceans.m3vz

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2. Turn on the following layers: • Buoy locations (Movie Links) • Elevation & Bathymetry

Earth’s oceans are monitored with buoys, satellites, and ships. The ocean monitoring buoys are placed in strategic locations in order to record information about ocean conditions. These buoys measure water temperature, salinity, and wave height. They also report weather conditions. The buoys are located throughout the Atlantic and Pacific Oceans in a buoy array. The data are sent back to the scientists via satellites. This image shows one set of buoy locations monitoring the North Atlantic. Before these types of buoys were invented and deployed, ocean scientists collected data from ships. To read more about ocean research from buoys consult the following link: Woods Hole Oceanographic, “A River Runs Through It: Chronicling the Currents of the North Atlantic” http://www.whoi.edu/page.do?pid=12455&tid=282&cid=2557

3. Select the Link Tool and then click the base of the link flag to see a movie showing how buoys are launched into the ocean.

4. Turn off Elevation and Bathymetry and Buoy Locations. Turn on Avg Annual Salinity/Temp of Oceans.

5. Click the open Analysis Window Button. Use Select… by Value to select records from Avg Annual Salinity/Temp of Oceans whose salinity is greater than 37. Type in a Result Name of High Salinity (>= 37). Click OK.

6. Observe the regions that are highlighted by using the Zoom to Selected Layer button.

7. Repeat this procedure to select a region with Salinity less than 34. Note: you will need to uncheck the Greater than box. Type in a Result Name of Low Salinity (< 34).

8. Under Highlight Mode choose “color selected yellow.” Click the radio buttons next to your selections to see the selected areas.

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QUESTION 1: Record the general location and pattern of the high and low salinity areas on your blank map and describe the patterns that you see in the table on the answer sheet.

9. When you are finished, turn off the highlighting of salinity by clicking the Show All radio button.

Part II. What factors contribute to dense water formation sites? The water in the Atlantic Ocean varies both in temperature and salinity. These variations contribute to the creation of areas of cold, salty, and dense water that sinks to the bottom of the ocean floor. Examine the factors that contribute to variations (increases or decreases) in salinity in the ocean.

1. Explore fresh water and salinity: a. Turn on Avg River Discharge (m^3/s) layer Rivers layer. b. Click the Open Analysis Window button. Use Select… By Spatial Relationship … By Crossing to select records from Top 5 river discharge rates which Cross records in Low salinity (< 34.) Click OK and accept the result name of Top 5 river discharge rates That Cross Low salinity (< 34.)

QUESTION 2: What type of water do these major rivers bring to the ocean?

c. Turn off all layers except Continents.

2. Investigate the relationship between evaporation and salinity: a. Turn on Avg Annual Salinity/Temp of Oceans layer. b. Use the Analysis tools to select the regions with high evaporation (NETEVAP > 70 cm/yr). Name the result: High Evaporation (> 70 cm/yr). c. Turn on Avg Annual Salinity/Temp of Oceans layer. Move the Net Annual Evaporation (E-P, cm/yr) layer above the Salinity layer in the layer list. d. Use the Analysis tools to Select…By Spatial Relationship …By Crossing to select records from High Salinity (>= 37) which Cross records in High Evaporation (> 70 cm/yr). Type in a Result Name of High Salinity and Evaporation.

Thought question: Is there a relationship between high salinity and high evaporation? Why might this be? What happens to a glass of salt water that is left to evaporate in the sun?

QUESTION 3. What is the relationship between evaporation and salinity? Describe your observations. e. Turn off the Avg Annual Salinity/Temp of Oceans layer.

3. Investigate the relationship between freezing and salinity: How does the freezing of salt water affect the ocean’s salinity? Hint: Think about the old ice cubes in your refrigerator, do you notice a coating on them?

In the process of freezing salt water, salt is literally squeezed from the ice. This process produces what is known as brine, very cold and salty water. Both salinity and temperature contribute to the density of a given sample of water. In the polar regions, scuba divers have filmed the brine coming from the bottom of sea ice as it is forming. It looks like tendrils of water streaming downward from the ice.

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4. For the Avg Annual Salinity/Temp of Oceans layer, use Select… By Value to select regions of very cold water, with nearly freezing temperatures (less than 5°C works.) Select Records from Avg Annual Salinity/Temp of Oceans whose TEMPC is less than 5. Choose Hide Unselected from the Highlight mode.

5. You should have a band of dark blue near the Polar Regions. This area represents an area of very cold and salty water.

6. Turn on the Dense Water Formation sites layer.

Thought question: Compare these areas of very cold and salty water to the areas the dense water formation sites. Can you see a pattern?

QUESTION 4. How does temperature affect water’s density?

QUESTION 5. Describe the location (latitude), temperature, and salinity and any other factors that you think contribute to these sites in the table on your answer sheet. Note: You may need to turn some layers on again to answer this question.

Characteristics of Dense Water Formation Sites Location / Region Polar or equatorial? Temperature Give a range Salinity High or low? Precipitation High or low? Evaporation High or low?

7. Turn off all layers except Continents.

Part III. How is Salinity Research in the North Atlantic Carried Out?

1. Turn on the Salinity Research Sites (Link) layer and make it active. Use the Zoom to Selected Layer button to zoom to this area of the North Atlantic.

2. Turn on the Elevation and Bathymetry layer.

Your map will show a dashed line. This line represents a dense water current running along the ocean floor. This is the important current that scientists are monitoring in their research.

3. Use the Link Tool and click the outlined area to access salinity graph data.

Look at the graphs linked to the regions listed below.

QUESTION 6: Describe the changes over time that you see in the linked salinity graphs on your answer sheet.

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Changes in Salinity in the Northern Atlantic

Region Change in salinity Observations or notes LS—Labrador Sea WIS—West Irminger Sea EIS—East Irminger Sea RR—Reykjanes Ridge FSC—Faroe-Shetland Channel DS—Denmark Strait SEI—Icelandic Basin

Thought questions: Why do you think the data collection sites are located where they are? Compare buoy location to bathymetry. Do you see a relationship? Where are the dense water formation sites?

4. Add the Salinity Research Sites layer to your map. Do you see a parallel between dense water sites and monitoring locations?

The Arctic Ocean receives water from many sources including: Arctic rivers, the Greenland ice sheet, and melt-water from the permafrost. As the Arctic warms each spring, fresh water moves into the ocean. Scientists from around the globe have observed changes in the salinity in the ocean.

QUESTION 7. What might you guess are the sources of the fresh water in the North Atlantic?

QUESTION 8. What might be causing the tropical waters to become saltier?

Conclude: Use any remaining time that you have to prepare a short (2 minute) presentation to share with your classmates. Record your observations on your answer sheet. Be able to answer these general and specific questions: • What is happening to the North Atlantic? • How do you know what you know? • What instruments do scientists use to observe the ocean’s temperature and salinity? • What two factors contribute to the density of ocean water? • How much has the salinity in the North Atlantic changed? • Why might this be important to climate?

After the class, close your My World project and do not save any changes.

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Lesson C: How are Climate and Ocean Currents Interlocked? KEY QUESTIONS: • Explain the relationship between dense water formation and thermohaline circulation patterns in the ocean. • How do currents affect climates, and what would be the impact on the climate of Europe if the thermohaline circulation patterns were to shift?

INTRODUCTION You have looked at Greenland and the North Atlantic separately. In this lesson, you are going to try to connect the two systems. Read below to see why.

Study Reports Large-Scale Salinity Changes in the Oceans Source: National Science Foundation; go to link for full release: http://www.nsf.gov/od/lpa/news/03/pr03145.htm Date: December 17, 2003 Arlington, Va.—Tropical ocean waters have become dramatically saltier over the past 40 years, while oceans closer to Earth’s poles have become fresher, scientists report in the December 18th issue of the journal Nature. These large- scale, relatively rapid oceanic changes suggest that recent climate changes, including global warming, may be altering the fundamental planetary system that regulates evaporation and precipitation and cycles fresh water around the globe. The study was conducted by Ruth Curry of the Woods Hole Oceanographic Institution (WHOI); Bob Dickson of the Centre for Environment, Fisheries, and Aquaculture Science in Lowestoft, U.K.; and Igor Yashayaev of the Bedford Institute of Oceanography in Dartmouth, Canada. … [E]vaporation concentrates salt in the surface ocean, increasing evaporation rates cause detectable spikes in surface ocean salinity levels. In contrast, salinity decreases generally reflect the addition of fresh water to the ocean through precipitation and runoff from the continents. Curry, Dickson, and Yashayaev analyzed a wealth of salinity measurements collected over recent decades along a key region in the Atlantic Ocean, from the tip of Greenland to the tip of South America. Their analysis showed the properties of Atlantic water masses have been changing—in some cases radically— over the five decades for which reliable and systematic records of ocean measurements are available, the scientists report. They observed that surface waters in tropical and subtropical Atlantic Ocean regions became markedly saltier. Simultaneously, much of the water column in the high latitudes of the North and South Atlantic became fresher. … Among other possible climate impacts, an accelerated evaporation-precipitation cycle would continue to freshen northern North Atlantic waters. The North Atlantic is one of the few places on Earth where surface waters become dense enough to sink to the abyss. The plunge of this great mass of cold, salty water helps drive a global ocean circulation system, often called the ocean conveyor. This conveyor helps draw warm Gulf Stream waters northward in the Atlantic, pumping heat into the northern regions that significantly moderates wintertime air temperatures, especially in Europe.

Part I. What Drives Deep Oceanic Motion? 1. Launch My World by double clicking the My World icon.

2. Open the project – Climate Change Impacts.m3vz

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3. Turn on the following layers: • Dense Water Formation Sites • Generalized Ocean Conveyor Belt (Movie & Internet Links)

4. Observe the spatial relationship between the dense water formation sites and the Ocean Conveyor Belt.

QUESTION 1. Describe the relationship between these two layers.

QUESTION 2. Do they have a pattern?

Note: It is important to understand that the red line represents warm surface currents, while the blue represents a cold and dense current creeping along the ocean floor. Think of the current as a 3-dimensional conveyor belt moving throughout the ocean basins.

5. Turn on the following layers on the map. • Lines of Latitude and Longitude • Elevation & Bathymetry (depth)

QUESTION 3. Describe the relationship of the dense water formation sites to Earth’s major ice sheets of Greenland and Antarctica. Note the latitudes where these sites are found.

6. Zoom to the areas of Dense Water Formation Sites using the Zoom Tool .

7. Look for relationships between the deep ocean conveyor current/dense water formation sites and ocean depth (bathymetry.) Do dense water sites occur in deep or shallow water?

Can Global Warming Cause Global Cooling? • Student Instructions • Page 42 STUDENT INSTRUCTIONS

QUESTION 4. Describe your observations of the relationships. ZOOM TO SELECTED LAYER TIP: Using the Zoom to Selected Layer is a 8. Turn on the Salinity Research Sites (Linked) layer and make it active. fast way to zoom to all of the records of the activated layer. To use this button be 9. Use the Zoom to Selected Layer button to zoom to this area of the sure to make the layer active and make North Atlantic. the layer visible by clicking the Hide/ Show Layer checkbox. 10. Turn off all layers except Continents.

The sinking of the very cold and dense brine begins the deep ocean currents. This sinking creates a void into which warmer waters from the equatorial regions are drawn.

Part II: What drives surface ocean motion? 11. Zoom back to a view of the entire world using the Zoom to All button.

About 80 percent of the world’s ocean water is on or near the surface of the ocean. It is moved by surface forces, most importantly, wind patterns.

12. Turn on the Global Wind Pattern and Surface Currents layer.

QUESTION 5. Do surface currents appear to be related to wind vectors or salinity patterns? How do you know?

13. Turn on the Avg Annual Salinity/Temp of Oceans layer. Turn it off when you are done.

Part III. Can you find the current climate connection? For this next section, you may want to change the legend of the continents layer to “name” and turn on the legend to show the names of the continents.

POINTER TOOL HINT: Use the pointer 1. Use the Zoom In Tool to zoom back to the North Atlantic region. tool to identify the countries. Notice that when you click a country, it is QUESTION 6. Based on the currents, what would you think the climate would highlighted in the legend. be like for these different countries? Fill in the chart on your answer sheet with your thoughts.

• Which continents are nearest warm currents and which are nearest cold currents? • Based on the currents, what would you think the climate would be like for these different continental regions? Choose several examples.

Can Global Warming Cause Global Cooling? • Student Instructions • Page 43 STUDENT INSTRUCTIONS

Current/Climate Connection in the Atlantic Basin

Continent Name Warm or cold current? Climate Class East coast of North America warm Hot summers, cool winters, tropical warm

2.Turn off the Global Wind Pattern layer.

3. Change the legend of the continents layer back to an open box (the first choice) instead of name.

4. Turn on the Climate Classes (Simple) layer. Observe the relationship between climate classes and the Surface Currents layer.

Part IV. How do surface ocean currents influence climate? 1. Turn on the Latitude and Longitude layer.

2. Move around the map using the Move Map tool. Compare regions at the same latitude but on different sides of continents and ocean basins such as Eastern and Western North American and Eastern U.S. and Western Africa.

3. Observe the relationship between latitude and temperature/climate. Hint: Is there a regular rule? Or is it more complex? Thought questions: • Examine the climate of North America’s East Coast vs. the climate of Europe. • What do you see? Why might the climates be different?

QUESTION 7. Can you generalize the relationship between ocean currents and climate classes? Record your observations in the table on the answer sheet. Give several examples.

Global Patterns of Climate and Currents Climate classes near WARM currents Temperature (warm or cold) Precipitation (wet or dry)

4. Turn on the Generalized Ocean Conveyor Belt. Does the conveyor seem to parallel the surface currents or does it have its own pattern? Your map should have the following layers displayed (turned on): • Continents • Lines of Latitude and Longitude • Generalized Ocean Currents • Surface Currents • Climate classes Simple

Can Global Warming Cause Global Cooling? • Student Instructions • Page 44 STUDENT INSTRUCTIONS

Part V. What would happen if the Global Conveyor Belt were to stop? The great ocean conveyor belt moves the majority of the ocean water. Because of the freshening of the North Atlantic the movement of this conveyor belt is threatened. This is because cold fresh water is not as dense as brine (very dense salt water.)

1. Zoom to the North Atlantic and turn on the Dense Water Formation Sites layer.

The greater the volume of dense water that sinks in the area around Greenland the more warm water is drawn to the polar region in the North Atlantic current.

2. On your map, use the Link Tool to see the 3-D animated version of this circulation created by Jack Cook of the Wood’s Hole Institute. You can also view an Ocean Conveyor animation here: http://www.whoi.edu/main/topic/ ocean-conveyor

3. Click the flags to see the movie. Choose “Today” first, then choose the “with additional freshwater” link second.

4. Compare the two movies. The arrows flowing over the top of the current represent the air currents that pick up and transfer heat to the continents. In the second video, the Greenland ice sheet is delivering additional freshwater to the North Atlantic, blocking the Gulf Stream. You may need to watch these videos more than once to understand them. Click the Web link provided in the project to read more about the graphics and the concerns scientists have about the patterns they are observing in the North Atlantic.

See the links below from Woods Hole Oceanographic Institution for more about North Atlantic ocean currents and changing climate: • “A River Runs Through It: Chronicling the Currents of the North Atlantic” http://www.whoi.edu/page/live. do?pid=12319&tid=282&cid=2557 • “Abrupt Climate Change: Should We Be Worried?” http://www.whoi.edu/page.do?pid=83339&tid=3622&cid=9986

How do we know what the climate of the past looked like? There are many methods that are used to find the climate records of the past. One method is to drill ice cores from the ice sheets. These cores are then chemically analyzed. They hold the story of the past climates in the chemical signature of a variety of ions.

Conclude Choose one of the following parameters. Discuss with your partner what you think would happen to your chosen parameter if the global conveyor belt of density currents were to slow or even stop. • Salinity distribution in the ocean • Ocean temperatures • Temperature patterns on land • Precipitation patterns on land • Climate classes on one continent bordering the Atlantic Basin

Can Global Warming Cause Global Cooling? • Student Instructions • Page 45 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling? Lesson A: Is Greenland Melting? Part I: Observing an Ice Sheet takes a Special Kind of Scientist 1. Describe the stations that you chose in the table below. What tools or equipment would you bring to survive there?

Station Name Elevation Comments Summit Swiss Camp CP-1 JAR 1 Choice 1 Choice 2

2. How many stations are above 2000 m? ______

3. Why might this distribution of stations be scientifically important? ______

4. What month would you expect to be the peak season for melting in Greenland? ______

Part II. Observing Changes in an Ice Sheet 5. Record your data in the chart below. Note the data is in the table that is active when there is blue highlighting on that selection.

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 46 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling?

Melt Extent Data Chart

Year Number of areas Number of weather stations reporting melt in the melt extent 1992 2002 Increase (subtract the records i.e. 2002 minus 1992)

6. What does melting do to an ice sheet?______

7. Use the Link Tool to open the linked graph and answer the following questions. • How many years has data been recorded for this graph?______• How much has the melt area increased since 1992?______• How many square km was the melt in 2002? ______• What other trends did you notice? ______

Part III. Glaciers on the Go 8. What is velocity? In what units is it measured? ______

9. Record the average distance between gates in the chart below.

10. Record the elevation of the gates in the chart below.

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 47 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling?

Glacier Velocity Gates Data and Notes

Average Distance between Gates Average Elevation of Gates Region of Greatest Glacial Velocity Region of Least Glacial Velocity

11. Record findings for the rest of the chart above. Is there any pattern to where the fast moving glaciers are located? How might this be related to weather patterns? ______

12. If the glaciers in southern Greenland are rapidly thinning, where does this melt water go? ______

Conclude: Use any remaining time that you have to begin to prepare a short (2 minute) presentation to share with your classmates. Record your observations on your answer sheet. Include key points and how you know what you know. Be sure to answer these questions:

13. What have you found is happening to Greenland? How do you know what you know? • How do scientists observe a glacier?______

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 48 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling?

• What instruments/tools do they use?______

• What is the data telling us about the ice sheet in Greenland?______

______

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 49 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling? Lesson B: Is the Salinity in the North Atlantic Changing? Part I: Getting a Global Perspective of the Ocean Research Process 1. Record the general location and patterns of the high and low salinity areas in the table below.

Patterns of Salinity in the Ocean

High salinity regions (give locations) Low salinity regions (give locations)

Part II. What factors contribute to dense water formation sites? 2. What do rivers bring to the ocean? ______

3. Is there a pattern between evaporation and salinity? ______

4. How does temperature affect water’s density?______

5. Describe the location (latitude), temperature, and salinity and any other factors that you think contribute to these sites in the table below.

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 50 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling?

Characteristics of Dense Water Formation Sites

Location / Region

Temperature

Salinity

Precipitation

Evaporation

Part III. How is Salinity Research in the North Atlantic Carried Out? 6. In the chart below, describe the changes over time that you see in the linked salinity graphs.

Changes in Salinity in Northern Atlantic

Region Change in salinity Observations or notes LS-Labrador Sea WIS- West Irminger Sea EIS- East Irminger Sea RR- Reykjanes Ridge FSC- Faroe-Shetland Channel DS-Denmark Strait SEI-Icelandic Basin

7. What might you guess are the sources of the fresh water in the North Atlantic? ______

8. What might be causing the tropical waters to become saltier?______

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 51 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling?

Conclude: Use any remaining time that you have to prepare a short (2 minute) presentation to share with your classmates. Record your observations on your answer sheet. Be able to answer these general and specific questions: What have you found is happening to the North Atlantic? How do you know what you know? • What instruments do scientists use to observe the ocean’s temperature and salinity? ______

• What two factors contribute to density of ocean water? ______

• How much has the salinity in the North Atlantic changed? ______

• Why might this be important to climate? ______

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 52 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling? Lesson C: How are Climate and Ocean Currents Interlocked? Part I. What drives Deep Oceanic Motion? 1. Describe the relationship between the Dense Water formation and Generalized Ocean Conveyor Belt layers. ______

2. Do they seem to have a pattern? ______

3. Describe the relationship of the dense water formation sites to Earth’s major ice sheets of Greenland, Antarctica, and the latitudes where they occur. ______

4. Look for relationships between the deep ocean conveyor current/dense water formation sites and ocean depth (bathymetry.) Do dense water sites happen in deep or shallow water? Describe your observations. ______

Part II: What drives surface ocean motion? 5. Do surface currents appear to be related to wind vectors? How do you know? ______

Part III. Can you find the current climate connection? 6. Based on the currents, what would you think the climate would be like for these different countries? Fill in the chart below with your thoughts.

Current/Climate Connection Continent Name Warm or cold current? Climate Class

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 53 STUDENT ANSWER SHEETS

Name______Date______Can Global Warming Cause Global Cooling? Part IV. How do surface ocean currents influence climate? 7. Can you make a generalization about the relationship between ocean currents and climate classes? Record your observations. Give an example of each type. ______

Global Patterns of Climate and Currents

Climate classes near WARM currents Temperature (warm or cold) Precipitation (wet or dry)

Climate classes near COLD currents Temperature (warm or cold) Precipitation (wet or dry)

Part V. What would happen if the global conveyor belt were to stop? Choose one of the following parameters. Discuss with your partner what you think would happen to your chosen parameter if the conveyor belt of density currents were to stop as depicted in the graphics in the lesson. • Salinity distribution in the ocean • Ocean temperatures • Temperature patterns on land • Precipitation patterns on land • Climate classes on one continent bordering the Atlantic Basin

Can Global Warming Cause Global Cooling? • Student Answer Sheets • Page 54 ANSWER KEY

Station Name Elevation Comments Summit 3208 m sunny, cold Swiss Camp 1,149 m buried in snow CP-1 2,022 m JAR 1 962 m Choice 1 Lowest is 323, highest is 3208—Summit cold, snowy lots of clothes Choice 2

2. How many stations are above 2000 m? ______11 stations are above 2000 meters

3. Why might this distribution of stations be scientifically important? ______To have a variety of locations ______being monitored. This is known as spatial variation.

4. What month would you expect to be the peak season for melting in Greenland? ______August and

______September are the peak season, after summer heating but before winter returns. However, in ______2003, 2004, and 2005 the melting lasted all the way into October. Melting is detected by the ______reflectance of the surface, when using satellite images (see description in text.)

Part II. Observing Changes in an Ice Sheet 5. Record your data in the chart below. Note the data is in the table that is active when there is blue highlighting on that selection.

Can Global Warming Cause Global Cooling? • Answer Key • Page 55 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling?

Melt Extent Data Chart

Year Number of areas Number of weather stations reporting melt in the melt extent 1992 868 1 2002 3075 8 Increase 2207 7 (subtract the records i.e. 2002 minus 1992)

6. What does melting do to an ice sheet? ______It causes the ice sheet to disintegrate. By increasing the ______melt water pools on top, it reduces the albedo.

7. Use the Link Tool to open the linked graph and answer the following questions. • How many years has data been recorded for this graph?______23 • How much has the melt area increased since 1992?______4.5 x10^5 • How many square km was the melt in 2002? ______7 x10^5 • What other trends did you notice? ______Answers will vary. The trend is generally up, but there was ______one downturn in 1992, due to the eruption of Mt Pinatubo.

Part III. Glaciers on the Go 8. What is velocity? In what units is it measured? ______Distance/time, in this case m/year; ______the X and Y-axis give directionality. This is a vector sum.

9. Record the average distance between gates in the chart below.

10. Record the elevation of the gates in the chart below.

Can Global Warming Cause Global Cooling? • Answer Key • Page 56 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling?

Glacier Velocity Gates Data and Notes

Average Distance It says 30 km in the reading, but measuring between Gates shows the variation from 20-30 kilometers Average Elevation 2000 m of Gates

Region of Greatest western side and southern tip Glacial Velocity

Region of Least north and east Glacial Velocity

11. Record findings for the rest of the chart above. Is there any pattern to where the fast moving glaciers are located? How might this be related to weather patterns? _ They______are on the eastern ______side, which does get the heavier snows. The south would be warmer because it is further south ______and more exposed to warm ocean currents.

12. If the glaciers in southern Greenland are rapidly thinning, where does this melt water go? _First______the water goes into the crevasses and speeds up the melting, then eventually, melt water _goes______into the ocean.

13. What have you found is happening to Greenland? How do you know what you know? • How do scientists observe a glacier? _With______automated weather stations, velocity gates, and ______radar mapping. They also learn from flying over the glacier.

Can Global Warming Cause Global Cooling? • Answer Key • Page 57 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling?

• What instruments/tools do they use? ______They use radar, weather, satellites, and direct ______measurement.

• What is the data telling us about the ice sheet in Greenland?______The Greenland ice sheet is melting.

______

Can Global Warming Cause Global Cooling? • Answer Key • Page 58 ANSWER KEY

Patterns of Salinity in the Ocean

High salinity regions (give locations) Low salinity regions (give locations)

Sargasso Sea

Mediterranean Sea

Part II. What factors contribute to dense water formation sites? 2. What do rivers bring to the ocean? _fresh______water

3. Is there a pattern between evaporation and salinity? ______The areas of high evaporation are also high _in______salinity.

4. How does temperature affect water’s density?______Water becomes denser when it is cold.

5. Describe the location (latitude), temperature, and salinity and any other factors that you think contribute to these sites in the table below.

Can Global Warming Cause Global Cooling? • Answer Key • Page 59 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling?

Characteristics of Dense Water Formation Sites

Location / Region Polar

Temperature Cold water – Polar regions

Salinity High salinity is tropical regions

Precipitation Low

Evaporation Low

Part III. How is Salinity Research in the North Atlantic Carried Out? 6. In the chart below, describe the changes over time that you see in the linked salinity graphs.

Changes in Salinity in Northern Atlantic

Region Change in salinity Observations or notes There is a decreasing trend in all LS-Labrador Sea the salinity graphs WIS- West Irminger Sea EIS- East Irminger Sea RR- Reykjanes Ridge FSC- Faroe-Shetland Channel DS-Denmark Strait SEI-Icelandic Basin

7. What might you guess are the sources of the fresh water in the North Atlantic? _The______glaciers of Greenland. (This will be a guess, since it isn’t taught in this lesson.)

8. What might be causing the tropical waters to become saltier? ______Increased evaporation or decreased _run-off______(Again not directly taught, so this is a thought question.)

Can Global Warming Cause Global Cooling? • Answer Key • Page 60 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling?

Conclude: Use any remaining time that you have to prepare a short (2 minute) presentation to share with your classmates. Record your observations on your answer sheet. Be able to answer these general and specific questions: What have you found is happening to the North Atlantic? How do you know what you know? • What instruments do scientists use to observe the ocean’s temperature and salinity? ______Buoys and satellites are used to observe the ocean.

• What two factors contribute to density of ocean water? ______Temperature and salinity, which are a result of weather patterns and insolation angle.

• How much has the salinity in the North Atlantic changed? ______There has been a significant change in the salinity.

• Why might this be important to climate? ______Again not directly taught, a thought question.

Can Global Warming Cause Global Cooling? • Answer Key • Page 61 ANSWER KEY

2. Do they seem to have a pattern? ______See above for a sample answer.

3. Describe the relationship of the dense water formation sites to Earth’s major ice sheets of Greenland, Antarctica, and the latitudes where they occur. The______dense water formation sites are near the poles at the high latitudes.

4. Look for relationships between the deep ocean conveyor current / dense water formation sites and ocean depth (bathymetry). Do dense water sites happen in deep or shallow water? Describe your observations. ______Dense water sites are in deep water and high latitudes near the poles.

Part II: What drives surface ocean motion? 5. Do surface currents appear to be related to wind vectors? How do you know? _Winds______and currents isolate the regions of high salinity into isolated pockets.

Current / Climate Connection Continent Name Warm or cold current? Climate Class

Eastern North America warm Hot summers, cool winters, tropical warm Coastal Africa Cold and warm Dry and warm since the current has submerged

Northern South America Warm Tropical warm

Europe Warm Warm, moist

Can Global Warming Cause Global Cooling? • Answer Key • Page 62 ANSWER KEY

Name______Date______Can Global Warming Cause Global Cooling? Part IV. How do surface ocean currents influence climate? 7. Can you generalize the relationship between ocean currents and climate classes? Record your observations. Give an example of each type. This______appears to be repetitive but it is the answer to the question above confirmed by the climate classes______layer. So it is an important step.

Global Patterns of Climate and Currents

Climate classes near WARM currents Temperature (warm or cold) Precipitation (wet or dry)

1. Mild Mid-latitude warm wet

2. Tropical Humid warm wet

Climate classes near COLD currents Temperature (warm or cold) Precipitation (wet or dry)

1. Polar cold dry

2. Dry cool cold dry

Part V. What would happen if the Global Conveyor Belt were to stop? Choose one of the following parameters. Discuss with your partner what you think would happen to your chosen parameter if the conveyor belt of density currents were to stop as depicted in the graphics in the lesson. • Salinity distribution in the ocean • Ocean temperatures • Temperature patterns on land • Precipitation patterns on land • Climate classes on one continent bordering the Atlantic Basin

Can Global Warming Cause Global Cooling? • Answer Key • Page 63