Getting to the Core of Climate Change

Getting to the Core of SCOPE ON THE SKIES Climate Change BY BOB RIDDLE

hat image may come to and permafrost. As such, the cryo- that study the climate history of mind when the word sphere is part of the hydrosphere the cryosphere (paleoclimatol- Wglacier is heard? Before and could be thought of as the ogy) study global ice in a variety answering that question, here is “frozen water” part of the Earth. of ways, including data and ob- another one: glaciers are part of The cryosphere plays a signifi- servations from Earth’s orbit, fly- the Earth’s “cryosphere”—so what cant role in our planet’s climate, overs with instrument-equipped is the cryosphere? The cryosphere and an understanding of how cli- airplanes, and a ground-based includes any place on our planet’s mate has changed in the past may collection of observations and surface covered with water in the provide information about what data (see Hunting for Ice on Hud- form of snow, ice on land or sea, to expect in the future. Scientists son Bay in Resources). NASA’s Operation IceBridge is an airborne flyover of the ice at | FIGURE 1: Ice core sample. both the North and South Pole. (Source: climate.nasa.gov/system/news_items/main_images/2616_ A variety of instruments docu- p1000526-1280px-90.jpg) mented changes in the gain or loss in the thickness and mass of ice on land and sea as well as glaciers. Data collected by IceBridge is added to data from previous and current NASA satellite missions, ICESat, ICESat-2, and the ESA’s satellite missions Cryo-Sat and CryoSat-2 (see Resources). All the airborne and satellite missions make some of the measurements using either radar or laser altime- try. As a side note, this is the tech- nology that allowed us to map the surface of Venus, for example (see Resources). Using either a radar or laser signal, the travel time to and from the surface is timed as the satellite or airplane passes over an

96 area. The differences in times are gen by its inclusion in the famil- what one has seen or read about converted into elevation or alti- iar chemical formula of H2O. This glaciers—perhaps an image of tude data. With this, the height is a water molecule where there sheets of ice, like those cover- of sea ice above the level of wa- are eight protons and eight neu- ing the Arctic and Antarctic, or ter or the altitude of ice sheets trons in the nucleus of the oxygen maybe a video showing calv- and glaciers may be measured atom (oxygen 16). Sometimes the ing of glaciers falling into the and used for determining the ice oxygen atom can have more than ocean. Many glaciers slowly thickness. Satellite and airplane eight neutrons in the nucleus— make their way to lower eleva- flyovers provide important data; oxygen 18 for example (8 protons tions as shown in the picture however, ground-based obser- and 10 neutrons), the heavy oxy- taken with the Earthkam camera vations and data collection is an gen. The ratio measured in an ice of snow, ice fields, and some gla- important component to piecing core sample is compared with a ciers in the Andes Mountains of together the connection between standardized ratio between the the southern Patagonia region of global ice and climate. two oxygens, and the difference Chile and Argentina (see Figure Instrumental to ground-based is used to determine trends in 2). Glaciers come in a variety of data collecting is the work of how atmospheric temperatures sizes based on location, and gla- glaciologists and the use of core have changed. For example, a ciers may be defined according to samples extracted from ice and high ratio of light oxygen would their respective location. Using snow fields. Like core samples suggest cooler temperatures. location, there are several catego- taken by geologists, ice core sam- ries of glaciers that could be di- ples and the materials they con- Glaciers vided into two somewhat broad tain—in addition to the ice and Remember that first question: groups—those in mountains and snow—contain clues to the cli- What image may come to mind those not in mountains. mate at the time the ice or snow when the word glacier is heard? Glaciers are large-scale objects was deposited. Once extracted, The answer may depend on that are incredible at weather- a core sample is only handled by glove-wearing scientists and technicians to avoid contaminat- ing the sample as it is carefully | FIGURE 2: Glacier Perito Moreno, Southern Patagonia. wrapped and packed for ship- (Source: Author using Earthkam) ment to a laboratory for analysis. In the laboratory, the core samples are often allowed to melt in a sealed container, making it possible for scientists to capture any trapped gases. The water itself is examined for particulate mate- rial like seeds and volcanic ash— anything collected from the melting ice is analyzed (see Figure 1). When the core sample gases are analyzed, scientists look for the ratio between oxygen atoms and an oxygen isotope, known as light oxygen and heavy oxygen, respectively. Students know oxy-

January/February 2021 97 ing and eroding the surface of ocean or driving through moun- on some of the seven Ecuadoran the Earth. Over time, continents tain glacier areas like the Tetons of mountains capped by snow and are changed and mountains wear Wyoming, the glaciers in Glacier glaciers. away. Ice, in terms of glaciers and National Park in Montana, or the Sadly, many of the glaciers in ice sheets, covers approximately glaciers of the Andes Mountains Ecuador and worldwide are re- 10% of the Earth’s surface. Ice in South America. However, how ceding, and some are disappear- sheets are now only located in often is it possible to know these ing—all at alarming rates as a Antarctica and Greenland; how- bodies of ice up close and person- result of changes in our climate. ever, in the past, ice sheets covered al? Glaciers, especially the high- Mountain glaciers, under most much of North America, forming altitude mountain glaciers of the climatic conditions, do not really the Great Lakes and creating the Andes in Ecuador, have a special disappear but typically recede fertile soils of the Midwest and the and personal place in my heart and then often regenerate them- cliffs of glacial till, loess, along the (also in my feet, my lungs, my selves. However, many of the cur- Missouri River near Mound City, knees!). Over the years I have had rently receding glaciers are not Missouri. several opportunities to spend recovering or regenerating at a In many locations glaciers are time on many of the mountains rate that balances or exceeds the typically viewed from a distance— in Ecuador, hiking, climbing, and rate of receding. The receding of maybe aboard a cruise ship when scrambling on their rocky surfac- a glacier or an ice sheet is a pro- watching glaciers calve into the es as well as traversing glaciers cess known as deglaciation, and

Visible planets

Mercury moves into the evening skies and passes by Jupiter during the first week of January. The in- nermost planet moves through inferior conjunction by the end of January and again passes by Jupiter and Saturn during the last week of February as a morning planet.

Venus is visible but low over the eastern horizon at sunrise but will soon be lost in the Sun’s glare as Venus moves into superior conjunction, on the opposite side of the Sun. Watch for Venus to show up as an evening planet during March.

Mars is visible over the southwestern horizon after sunset. Follow Mars as it moves eastward along its orbit. With binoculars, watch as it passes by the outer planet Uranus during January and slowly but steadily catches up with the open star cluster the Pleiades by the end of February.

Dwarf planet Ceres is over the southwestern horizon at sunset; however, it has an apparent magnitude that is too dim to seen without some optical assistance.

Jupiter starts the new year close to Saturn and very low over the western horizon at sunset, and by the middle of the month the Sun has caught up with Jupiter as Jupiter moves into conjunction with the Sun. Watch for Jupiter to reappear in the morning skies by the end of February.

Saturn is close to Jupiter and like Jupiter will move through conjunction with the Sun and will become visible as a morning planet by the end of February.

98 SCOPE ON THE SKIES this represents the loss of a part the lifestyles and environment ies of Riobamba and Guaranda, a of the cryosphere. On the basis of of people and animals living in long-time source of income came elevation, a glacier has a line of their shadows? As glaciers recede, from blocks of ice carved from the equilibirum, an elevation at which what impact does this have on the glaciers on Chimborazo and was the amount of snow and ice accu- environment and the people and sold locally (see “The Story of the mulation is approximately equal animals living in those areas? One Last Ice Merchant” in Resources). to the amount of ablation, or loss, may not often think of glaciers in Volcan Chimborazo is the tall- of glacial ice. This elevation varies those terms, but to many people est of the mountains in Ecuador based on local geographical cir- and animals the nearby glaciers at 20,500 feet (6100 m). It is one cumstances; however, in Ecuador are especially important. Consider of many snow and ice-capped this elevation is at approximately that glaciers may be the primary mountains within Ecuador. Chim- 16,800 feet (5,120 m). source of water for a community, borazo has the distinction of hav- Two of the seven snow-capped or even a source of income. In Ec- ing its summit further from the volcanoes in Ecuador, Carihuai- uador, approximately 2% of drink- Earth’s core than the summit of razo (16,486 feet [5,025 m]) and ing water comes from glaciers so Mt. Everest at 29,029 feet (8800 m). Illiniza South (15,580 feet [4,750 the impact on some communities This is possible because Chimbo- m]) have summits lower than the varies. However, the impact on razo, at about 1o S latitude, takes line of equilibrium and have lost plants and animals may be more advantage of the Earth’s equato- or are expected to lose much of severe as less amounts of snowfall rial bulge. Over time, the rotat- their respective glaciers over the decrease the amount of available ing Earth has become slightly next decade. Carihuairazo has water (see Figure 3). Much of the flattened at the poles into a shape already lost 90% of its glacier ice. water source for the city of Cuen- known as an oblate spheroid. The It is not unusual for glaciers to ca Ecuador, for example, comes Earth has an equatorial circumfer- grow and recede; however, stud- from slowly receding glaciers in ence of 24,901 miles (40,074 km), ies of glaciers in the Andes show the Cajas Mountains National while the Earth’s polar circumfer- an increase in the decrease that is Park. Further north, near the cit- ence is 21,600 miles (34,762 km). linked with climate change and the subsequent gradual increase in average air temperature. | FIGURE 3: Volcan Chimborazo and three Vicuna, small llama- It is interesting to note that the like animals living at altitudes above 14,000 feet (94,267 Perito Moreno Glacier (see Fig- m). (Source: Author) ure 2) is one of very few glaciers worldwide that appears to not be affected by climate change or losing mass. The area around the glacier contains approximately one-third of all freshwater in the world.

Among the glaciers of Ecuador How many of us think of mountains and glaciers from a cultural perspective? How do glaciers and their tall mountain hosts fit into

January/February 2021 99 Coincidentally, when students | FIGURE 4: The small glacial lake on Volcan Chimborazo. take part in an Eratosthenes Mea- surement project, they are mea- (Source: Author) suring the polar circumference of the Earth. Volcan Chimborazo, located within a National Park, is an eas- ily approachable mountain for high-altitude hiking and summit attempts. The road leading to the park entrance is over 14,000 feet in elevation, and the drive or hike to the lower Refugio (climber’s hut) takes you to approximately 15,748 feet (4,800 m). From there, trails lead to the upper Refugio 16,732 feet (5,100 m) and the summit. Glacial loss on Chimborazo and other nearby snow-capped mountains is due to a combination of climate change and ash fall from active volcanos like Volcan Tun- gurahua south of Chimborazo. | FIGURE 5: Remnants of the receded and buried glacier, One of the most noticeable chang- elevation 17,120 feet (5,218 m). es I have observed, especially on Chimborazo, is the reduction in (Source: John Riddle the size of the glacier along one of the summit routes. This was a glacier that had carved a small u- shaped valley ending near the upper Refugio. During my first time there in 2005, we hiked to that glacier and practiced ice climbing after crossing a small lake of glacial melt. During a visit there in 2019 the lake was still there but all that was left of the glacier were large blocks of ice covered by rocks and dirt from landslides (see Figures 4 and 5). The summit of Volcan Chimbo- razo was first reached in the 1890s by European mountain climber Edward Whymper. Among other accomplishments, he was known

100 SCOPE ON THE SKIES for his climbing of the Matter- There are many resources avail- work of scientists who study gla- horn and the tragic loss of several able for us and our students that ciers and the importance of their climbers during that climb. Safety provide more information about research to the understanding of is always a concern for mountain the status and importance of ice climate change at both the local climbing, and Edward Whymper, on our planet and the impact that community level as well glob- in one of his books, offers some global ice has on climate. As I am ally (see Resources for two articles sound advice on that topic—ad- writing this column (summer from Atlas Obscura: “An Elergy vice that also applies to a per- 2020), more weekly news is being for Columbia’s Tropical Glaciers” son’s outlook on their education. reported about ice loss in Green- and “Glacial Research at the Third How do you think the following land and the Arctic, the thawing Pole”). At this time of year some of quote from Edward Whymper of permafrost, and unusually high us are in locations where snow core could relate to your education: summer temperatures north of the samples could be obtained using “Do nothing in haste; look well Arctic Circle and in many other lo- local snow falls, allowing students to each step, and from the begin- cations around our planet dealing to replicate some of the work that ning think what may be the end” with rising temperatures. Students scientists do. There are also sev- (Whymper, 1871). can find stories to read about the eral cryosphere-related activities

January February 01 Waning gibbous Moon near Sun enters the astronomi- 03 Moon at perigee: 229,969 Beehive Open Star Cluster cal constellation of Capri- miles (370,100 km) 02 Earth at perihelion: 0.9833 corn the Sea Goat 04 Last quarter Moon AU; 91,403,445 miles; Sun Not Really in the as- 06 Moon at descending node 147,099,586 km trological constellation of Waning crescent Moon Aquarius the Water Bearer 03 Quadrantid shower: (Waning near Antares gibbous moonlight inter- 21 Moon at apogee: 251,282 07 Mars spring equinox feres) miles (404,400 km) 08 Mercury at inferior con- 06 Last quarter Moon 23 Mercury at eastern elonga- junction 09 Moon at perigee: 228,292 tion: 18.6° E Moon at southern most miles (367,400 km) Saturn at solar conjunction declination: 25° S 10 Moon at descending node 24 Moon at ascending node 11 New Moon 11 Waning crescent Moon near 26 Moon at northern most 15 Galileo day Venus declination: 24.9° N 17 The Sun enters the astro- 12 Moon at Southernmost 28 Waxing gibbous Moon near nomical constellation of declination: 24.9° S Beehive Open Star Cluster Aquarius the Water Bearer New Moon Full Moon 18 Moon at apogee: 251,345 14 Waxing crescent Moon near Jupiter at solar conjunction (404,500 km) Mercury 29 Waning gibbous Moon near Waxing crescent Moon 17 Mars—Uranus conjunction Regulus near Mars 20 First quarter Moon

January/February 2021 101 students could do. A good starting RESOURCES images/147086/hunting-for-ice- page to learn about the cryosphere About the Cryosphere—mynasadata. on-hudson-bay?src=eoa-iotd and its components is “About the larc.nasa.gov/basic-page/about- Ice Cores: Gathering Data— betterlesson.com/lesson/635267/ Cryosphere” on the NASA website cryosphere Climate Change: How Do We Know?— ice-cores-gathering-data (see Resources). climate.nasa.gov/evidence/ Ice Core Mini Lesson—info.thinkfun. Are ice and glaciers unique to Core Questions—climate.nasa.gov/ com/stem-education/cool- our planet? Certainly not. Images news/2616/core-questions-an- classroom-activity-ice-core-mini- returned from space probes have introduction-to-ice-cores/ lesson shown us ice on many of the outer Create Classroom Ice Cores—byrd.osu. MOSAiC Curriculum Materials—mosaic. colorado.edu/mosaic-and-polar- planet moons and in craters on edu/create-classroom-ice-cores Earthkam—earthkam.org related-lessons-and-curricula our Moon and the inner planet An Elegy for Colombia’s Tropical NSIDC All About Glaciers—nsidc.org/ Mercury; ice has also been seen on Glaciers—atlasobscura.com/ cryosphere/glaciers/ dwarf planet Pluto. There are po- articles/what-is-a-tropical-glacier NASA Operation IceBridge—icebridge. lar ice caps, like those on Earth, at ESA CryoSat Mission—earth.esa. gsfc.nasa.gov/ both poles on Mars. Some recent int/web/guest/missions/esa- NASA ICESat-2—icesat.gsfc.nasa.gov/ NASA’s Mars 2020 Rover Mission— observations of the river channel- operational-eo-missions/cryosat Galileo Day—www.galileoday.org/ mars.nasa.gov/mars2020/ like features on Mars have led Glacial Research at the Third Pole— NASA Space Laser Missions Map some planetary scientists to sug- atlasobscura.com/articles/glacier- 16 Years of Ice Sheet Loss— gest that features like the river research-at-the-third-pole www.jpl.nasa.gov/news/news. channels could have been formed Glaciers of (USA) North America—usgs. php?feature=7654 by glaciers. gov/faqs/where-are-glaciers-found- NOAA Climate at the Core—climate. • continental-north-america?qt- gov/news-features/climate-tech/ news_science_products=0#qt- climate-core-how-scientists- REFERENCE news_science_products study-ice-cores-reveal- Whymper, E. (1871). Scrambles Global Ice Viewer—climate.nasa.gov/ earth%E2%80%99s-climate amongst the Alps in the years interactives/global-ice-viewer/#/ NSF Ice Core Facility—icecores.org/ 1860–69. London, England: John Hunting for Ice on Hudson Bay— Paleoclimatology: The Ice Core Murray. earthobservatory.nasa.gov/ Record—earthobservatory.nasa. gov/features/Paleoclimatology_ IceCores Parker Solar Probe—parkersolarprobe. jhuapl.edu/ For students Radar Imaging of Venus—history.nasa. 1. What types of data could an ice core provide? See Resources for gov/JPL-400-345/text.htm The Story of the Last Ice Merchant— links to some ice core activities. thelasticemerchant.com/about- 2. What do you know about glaciers? See Resources for links to NSIDC the-film/the-story/ (National Snow and Ice Data Center) website “All About Glaciers” The Last Ice Merchant Video—youtu.be/ PAeUC0-v5x4 and the “Global Ice Viewer” website. What’s Causing Sea-Level Rise? Land 3. Explore historical maps of glaciers at the World Glacier Monitoring Ice Vs. Sea Ice—jpl.nasa.gov/edu/ Service website (see Resources). teach/activity/whats-causing-sea- level-rise-land-ice-vs-sea-ice/ 4. Are there any glaciers in the United States? Go to the USGS website What’s the Mystery Behind West to find out (see Glaciers of North America in Resources). Antarctica’s Disappearing Ice?—climate.gov/news- 5. Where is the closest glacier to you? Download the WGMS Glacier features/featured-images/ App (Android and IOS) and find out (see World Glacier Monitoring what%E2%80%99s- Service in Resources). mystery-behind-west- antarctica%E2%80%99s-

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disappearing-ice images/6399/glacier-national-park nasa.gov/science/ice-sheets-and- World Glacier Monitoring Service— Glacier Photograph Database glaciers/ wgms.ch/products_fog_maps/ (Search)—nsidc.org/data/glacier_ Ice Melt Linked to Accelerated Regional photo/search/ Freshwater Depletion—jpl.nasa.gov/ Huge East Antarctic Glacier Especially news/news.php?feature=7669 ADDITIONAL RESOURCES ON Susceptible to Climate Impacts— Jakobshavn Glacier—climate.nasa.gov/ ICE AND GLACIERS https://go.nasa.gov/2WRVSr8 news/2882/jakobshavn-glacier- 360 Degree Images from an Arctic Ice in Motion—www.nasa.gov/feature/ grows-for-third-straight-year/ Expedition—poly.google.com/view/ goddard/2019/ice-in-motion- Oceans Melting Greenland—omg.jpl. beIkmpdxevd satellites-capture-decades-of- nasa.gov/portal/ Dramatic Glacial Melt—climate.nasa. change What Types of Glaciers Are There?— gov/climate_resources/4/graphic- Images of Change—climate.nasa.gov/ nsidc.org/cryosphere/glaciers/ dramatic-glacier-melt/ images-of-change?id=699#699- questions/types.html? Glacier National Park— icelands-ok-glacier-melts-away World Glacier Monitoring Service— earthobservatory.nasa.gov/ Ice Sheets in Motion—gracefo.jpl. wgms.ch

Bob Riddle ([email protected]) is a science educator in Lee’s Summit, Missouri. Visit his astronomy website at www. bobs-spaces.net.

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