1 Chapter 10 Global Effects Lecture #21 HNRT 228 Spring 2013 Energy and the Environment Adapted from UNM and USGS

2 Chapter 10+ Overview Earth as a planet The polar regions and sea ice effects The stratospheric ozone situation Another look at greenhouse gasses Climate change Global warming

3 iClicker Question Which of the following layers of the atmosphere is highest above the surface of the Earth? ATroposphere BStratosphere CThermosphere DMesosphere EOzone Layer

4 iClicker Question What is the primary ingredient of the Earth's atmosphere? ANitrogen BOxygen CNitrogen and oxygen in equal parts DHydrogen ECarbon dioxide

5 iClicker Question In what part of the atmosphere does weather occur? AHydrosphere BStratosphere CIonosphere DTroposphere EAll of the above

6 iClicker Question How rapidly a planet loses its atmosphere depends on the planet's I.mass II.atmospheric composition III.temperature IV.rotation period AI & II BIII & IV CI, II, & III DII, III, & IV EI, II, III, & IV

7 iClicker Question The presence of Earth’s magnetic field is a good indication that Athere is a large amount of magnetic material buried near the North Pole. Bthere is a quantity of liquid metal swirling around in the Earth's core. Cthe Earth is composed largely of iron. Dthe Earth is completely solid. Ethere are condensed gasses in the core of the Earth.

8 The Earth

9 General Features Mass: M Earth = 6 x g Radius: R Earth = 6378 km Density:  = 5.5 g/cm 3 Age: 4.6 billion years

10 Earth's Internal Structure Crust: thin. Much Si and Al (lots of granite). Two-thirds covered by oceans. How do we know? Earthquakes. See later Mantle is mostly solid, mostly basalt (Fe, Mg, Si). Cracks in mantle allow molten material to rise => volcanoes. Core temperature is ~6000 K. Metallic - mostly nickel and iron. Outer core molten, inner core solid. Atmosphere very thin

11 Earth's Atmosphere 78% Nitrogen 21% Oxygen gas is ionized by solar radiation ozone is O 3, which absorbs solar UV efficiently, thus heating stratosphere commercial jet altitudes room temperature Original atmosphere changed over time. Atmosphere today is largely due to volcanoes and life (especially plant).

12 Ionosphere Particles in the upper reaches of the atmosphere are ionized by the sun. Radio signals below ~20 MHz can “bounce” off the ionosphere allowing communication “over the horizon”

13 Convection Earth's surface heated by Sun. What would happen if it couldn't get rid of the energy as fast as it gets in? Convection causes both small-scale turbulence and large scale circulation patterns. It also occurs within Earth, on other planets, and in stars. Convection also occurs when you boil water, or soup. Think of Earth's surface as a boiling pot!

14 The Greenhouse Effect Main greenhouse gases are H 2 O and CO 2. If no greenhouse effect, surface would be 40 o C cooler!

15 iClicker Question: The dinosaurs were most likely wiped out by: A: disease B: hunting to extinction by cavemen C: a giant meteor impact D: the close passage of another star

16 iClicker Question: A leading cause of Global Warming is: A: Increased soot (smog) in the atmosphere. B: Increased carbon dioxide in the atmosphere. C: The Earth is getting closer to the sun. D: The luminosity of the sun is steadily increasing.

17 iClicker Question: The Greenhouse effect would not occur if: A: The Earth had no atmosphere. B: The amount of carbon dioxide doubled. C: We got rid of all the forests. D: The Earth didn’t have an ocean.

18 Burning carbon-containing fossil fuels produces carbon dioxide. (Combustion) C + O 2 CO 2 Pollution Global Warming: The Greatest Threat © 2006 Deborah L. Williams

19 CO 2 : Most Significant Greenhouse Gas Source: ACIA 2004 Jennifer Allen graphic Global Warming: The Greatest Threat © 2006 Deborah L. Williams CO 2 CH 4  Humans have increased carbon dioxide (CO 2 ) in the atmosphere by more than 35% since the Industrial Revolution. (National Oceanic and Atmospheric Administration 2006)  The most carbon dioxide in 650,000 years. (IPCC 2007)

20 Temperature Measurements  “Warming of the climate system is UNEQUIVOCAL” (IPCC 2007)  Top 11 warmest years on record have all occurred in the last 12 years. (IPCC 2007)  2006 warmest year on record in continental US. (NOAA 1/07)

21 Alaska as Ground Zero for Warming In past 50 years, Alaska: Temperatures have increased 4 o F overall (National Assessment Synthesis Team) Worldwide: Temperatures have increased Slightly more than 1 o F (IPCC 2007) Surface Air Temperature Trends Global Warming: The Greatest Threat © 2006 Deborah L. Williams Chapman and Walsh, 2004

22  Snow and sea ice reflect 85-90% of sun’s energy.  Ocean surface and dark soil reflect only 10-20%. The Albedo Effect “White shirt versus Black shirt” Why has Alaska warmed the most? Increased melting of snow and sea ice Increased melting of snow and sea ice More of sun’s heat energy is absorbed More dark earth and ocean surface is exposed More dark earth and ocean surface is exposed Land or water warms faster Global Warming: The Greatest Threat © 2006 Deborah L. Williams (ACIA 2004)

23 Source ACIA, 2004 Jennifer Allen Animation  An area twice the size of Texas has melted away since 1979 (over 20% decrease). (National Snow and Ice Data Center 2005)  Ice 40% thinner. (Rothrock,D.A, et al. 1999)  Ice only 6 – 9 feet thick at North Pole ( NOAA FAQ 2007).  Northwest passage opened Aug 21, 2007 Impacts in Alaska 1. Melting Melting Sea Ice | | | | | Arctic Sea Ice Extent (millions of sq. km.) Source: NSIDC, 2005 ARCTIC SEA ICE AREA Global Warming: The Greatest Threat © 2006 Deborah L. Williams

24 Impacts in Alaska 1. Melting Global Warming: The Greatest Threat © 2006 Deborah L. Williams Melting Sea Ice Arctic Ocean could be ice free in summer by 2040 (U.S National Center for Atmospheric Research 2006). “Our research indicates that society can still minimize the impacts on Arctic ice.” Dr. Marika Holland, National Center for Atmospheric Research

25 Impact World-wide 1. Melting Global Warming: The Greatest Threat © 2006 Deborah L. Williams Impact on Ski Industry In the US skiing is a $5B industry 2006 saw a 78% decline in skiers visiting the pacific northwest US Ski Seasons have shortened by 1 day/year for the last 20 years Many European ski resorts below 1800 m (6000 ft) will close 50 to 90% of Alpine glaciers will be gone by 2100 Some resort to snowmaking Expensive Requires lots of water Requires lots of energy In New Mexico, many ski areas can’t open until after Xmas

26 Impacts in Alaska 1. Melting  The rapid retreat of Alaska’s glaciers represents about 50% of the estimated mass loss by glaciers through 2004 worldwide. (ACIA 2004)  Loss of over 588 billion cubic yards between ’61 and ’98. (Climate Change 11/05)  Alaska’s glaciers are responsible for at least 9% of the global sea level rise in the past century. (ACIA 2004) Glacier Bay (Riggs Glacier) USGS photo Bruce Molnia photo Glacial Retreat 2003 Matt Nolan photo Austin Post photo 1958 McCall Glacier

27 Melting of the Greenland Ice Sheet According to NASA scientists, the Greenland ice sheet is melting faster than it is being replaced, contributing to sea level rise The loss of ice from Greenland doubled between 1996 and 2005 From 1996 to 2000, the largest acceleration and mass loss came from southeast Greenland From 2000 to 2005, the trend extended to include central east and west Greenland It is estimated that 69 per cent of the ice-mass loss in recent years came from eastern Greenland

28 Greenland ice is declining faster than expected Between 2003 and 2005 the low coastal areas of Greenland lost 155 gigatons of ice per year due to excess melting while the high elevation interior gained 54 gigatons annually from excess snowfall Between 2004 and 2006, the rate of melting accelerated, with the massive ice sheet melting two and one-half times faster than the previous two-year period Greenland lost roughly 164 cubic miles of ice from April 2004 to April 2006—more than the volume of the North American Great Lake Erie

29 Greenland Ice Sheet Dramatic ice mass losses concentrated in the low- elevation coastal regions, with nearly half of the loss coming from southeast Greenland NASA Earth Observatory

30 Greenland Ice Sheet Greenland is now losing 20 percent more mass than it receives from new snowfall each year. NASA Earth Observatory

31 Greenland Ice Sheet University of Colorado, CIRES

32 Melting of ice in Greenland : A significant increase in the melting area has been observed along the edge of the ice cap in Greenland. NASA Earth Observatory

33 Retreat of Ice and Snow in Greenland NASA Earth Observatory Ice loses in Greenland range from 5 to 25 centimeters of water equivalent per year

34  This May 2005 picture of Helheim Glacier, demonstrates high calving activity associated with faster glacial flow Helheim glacier, located in southeast Greenland, is now one of the fastest moving glaciers in the world : These images show the retreat of Helheim glacier’s calving front Calving of Helheim Glacier, Greenland The glacier’s peak rate of flow has increased from 8 km/yr in 2000 to 11 km/yr in 2005

35 Dramatic changes in Arctic Sea Ice Imagine an ice- free Arctic

36 Evidence of extensive snowmelts in West Antarctica January 2005: Areas of extensive snowmelt (shown in yellow and red) have been discovered by a team of NASA and university scientists in response to warmer temperatures in west Antarctica. The combined area affected is as big as California. NASA Jet Propulsion Laboratory

37 Breakup of Larsen ice shelf (Antarctic Peninsula) 220 metres thick Larsen B shelf existed for at least 400 years prior to breakup

38 Disintegration of the Larsen B Ice Shelf, Antarctic Peninsula The ice shelf disintegrated suddenly in March 2002 due to warm summer temperatures NASA Earth Observatory

39 Breakup of Antarctica’s Ross Ice Shelf An iceberg (B-15J) of size of a small United States state cracked off the Antarctica’s Ross Ice Shelf in March 2000 On February 1, 2007, three new icebergs were formed due to the break up of the original iceberg NASA Earth Observatory

40 Breaking Off Filchner Ice Shelf Antarctica Filchner Ice Shelf is the largest ice shelf on the planet In 1986 the front edge of Ice Shelf broke off into three enormous icebergs

41 Calving of Ninnis Glacier Antarctica 22 January 2000: The Ninnis Glacier Tongue soon after the initial calving 5 February 2002: Iceberg split into two sections and started moving away from Ninnis Glacier

42 Cracks on Drygalski Ice Tongue Antarctica The ice tongue was discovered in February 2005: Drygalski calved an iceberg Image shows cracks formed by time and ocean currents

43 Shrinking Lake Chad shared by Nigeria, Niger, Chad and Cameroon Persistent drought has shrunk the lake to about a tenth of its former size 1972: Larger lake surface area is visible in this image 2001: Due to regionally drying climate and human demand for fresh water, Lake Chad is fraction of what is once was 2004: In many places, the green of wetlands is being replaced by drifting sand dunes (tan ripples mixed with green)

44 Shrinking Breidamerkurjökull Glacier Iceland : Images show glacier has receded and the glacial lake at its tip has enlarged

: Images show Degradation of forest area 2001: Between 1984 and 1999, 38 per cent of forests were degraded Ayles Ice Shelf, Ellesmere Island, Canada Ayles Ice Shelf on Ellesmere Island, broke free on August 13, 2005 and drifted out to the sea NASA Earth Observatory

46 Disappearing Icecap of Mt. Kilimanjaro, Tanzania Africa’s highest mountain with a forest belt having rich diversity of ecosystems 1976: Glaciers covered most of the summit 2000: The glaciers had receded alarmingly

47 Retreat of Gangotri Glacier, India NASA Earth Observatory Gangotri glacier has retreated more than 850 meters, in the last 25 years It has retreated more than 76 meters from 1996 to 1999

48 Glacial Lakes and Glacial Lake Outburst Floods Jeffrey Kargel, USGS/NASA JPL/AGU Glacial lakes are formed due to the melting of ice and snow from glaciers Due to the faster rate of melting from the glaciers, possibly due to global warming, water is accumulating at an increasing rate in these lakes Sudden outburst results in Glacial Lake Outburst Flood (GLOF) downstream causing destruction of life and property Glacial Lakes in the Bhutan-Himalaya Region

49 Retreat of Upsala Glacier, Argentina NASA Earth Observatory The Upsala glacier has retreated more than 4 kilometers since late 1960’s to mid 1990’s and continues to retreat January 2004 position

50 Retreat of San Quintin Glacier, Chile NASA Earth Observatory The San Quintin Glacier appears to be losing mass and retreating

51 Impacts in Alaska 3. Animals Animals at Risk  Rising temperatures  Shrinking habitat  Food harder to get  Expanding diseases  Competition Polar bears Walruses Ice seals Caribou Black guillemots Kittiwakes Salmon Arctic grayling

52 Inundation  Sea level has increased 3.1 mm/year between 1993 and 2003 (IPCC 2007).  This is times faster than during the last 3,000 years (ACIA 2004).  meters of sea level rise by 2100 if 3 times pre- industrial CO2 or 1% increase/year (Overpeck et al. 2006).

53 Inundation Inundation from Four Meter Sea Level Rise (or, 1m rise + 3m storm surge) Weiss and Overpeck, 2006

54 Photo courtesy of 7summits.com What We Can Do 1. Is it Achievable? 2. Action Is Possible at Every Level Individual Corporate Local State Federal International 3. Some Steps R E D U C E C O 2 E M I S S I O N S Global Warming: The Greatest Threat © 2006 Deborah L. Williams

55 What We Can Do Wind Power Global Warming: The Greatest Threat © 2006 Deborah L. Williams

56 Measuring Your Carbon Footprint Major Carbon Contributors:  Electric Consumption  Gas/Heating Oil Consumption  Car and Miles Driven  Miles Flown  Recreational Vehicle Use Average Footprint is 30,000 pounds

57 Conservation: Three Examples Unplug Appliances  Vampires!  43 billion kWH lost/year in US  Est: 1,000 lbs/year/person Pump Up Tires  4 million gallon of gas wasted daily in US  Extends life of tires by 25%  Est: 1,000 lbs/year/person Lower Thermostat  2 degrees  Est: 2000 lbs/year/person What We Can Do

58 Energy Efficiency: Two Examples Compact Fluorescents  Four to six times more efficient  Est: for each bulb converted, save about 100 lbs/year Bus/Walk/Bike  Save money on fuel and maintenance  Est: 5,000 lbs/year

59 Earthquakes They are vibrations in the solid Earth, or seismic waves. Two kinds go through Earth, P-waves ("primary") and S-waves ("secondary"):

60 How do they measure where Earthquakes are centered? * * * seismic stations

61 Like all waves, seismic waves bend when they encounter changes in density. If density change is gradual, wave path is curved. S-waves are unable to travel in liquid. Thus, measurement of seismic wave gives info on density of Earth's interior and which layers are solid/molten. But faint P waves seen in shadow zone, refracting off dense inner core Curved paths of P and S waves: density must slowly increase with depth Zone with no S waves: must be a liquid core that stops them No P waves too: they must bend sharply at core boundary

62 Earth's Interior Structure Average density Crust Mantle Core 5.5 g/cm 3 3 g/cm 3 5 g/cm 3 11 g/cm 3 Density increases with depth => "differentiation" Earth must have been molten once, allowing denser material to sink, as it started to cool and solidify.

63 Earthquakes and volcanoes are related, and also don't occur at random places. They outline plates. Plates moving at a few cm/year. "Continental drift" or "plate tectonics"

64 When plates meet... 1) Head-on collision (Himalayas) 2) "Subduction zone" (one slides under the other) (Andes) 3) "Rift zone" (two plates moving apart) (Mid-Atlantic Ridge, Rio Grande) 4) They may just slide past each other (San Andreas Fault) side view top view => mountain ranges, trenches, earthquakes, volcanoes

65 iClicker Question: Sunlight absorbed by the Earth’s surface is reemitted in the form of? A: radio waves B: infrared radiation C: visible radiation D: ultraviolet radiation E: X-ray radiation

66 iClicker Question: What steps are you willing to take to reduce your carbon dioxide footprint? A: Walk/bike/bus to work B: Unplug appliances when not in use C: Replace light bulbs with compact fluorescents D: Wash clothes in cold or warm water E: Buy a Prius

67 The Mid-Atlantic Ridge is a rift zone.

68 What causes the drift? Convection! Mantle slightly fluid and can support convection. Plates ride on top of convective cells. Lava flows through cell boundaries. Earth loses internal heat this way. Cycles take ~10 8 years. Plates form lithosphere (crust and solid upper mantle). Partially melted, circulating part of mantle is asthenosphere.

69 Pangaea: 200 million years ago, all the continents were close together.