Living Environment Ms Endrina 10172008 Ms Waldinger Do

Living Environment Ms. Endrina 10/17/2008 Ms. Waldinger Do Now: Describe in complete sentences the difference betwee global warming and the greenhouse effect. Aim: Will Human-Induced Climate Change Destroy the World?

Introduction • Is the world getting warmer? • If so, are the actions of mankind to blame for earth’s temperature increases? • What can/should be done about these issues? • Are the potential resolutions worth the cost to implement them?

History of Earth’s Climate • Earth formed ~4. 6 billion years ago • Originally very hot • Sun’s energy output only 70% of present • Liquid water present ~4. 3 billion years ago (zircon dating) • Much of earth’s early history erased during late heavy bombardment (~3. 9 billion years ago)

History of Earth’s Climate • Life appeared ~3. 8 billion years ago • Photosynthesis began 3. 5 -2. 5 billion years ago § Produced oxygen and removed carbon dioxide and methane (greenhouse gases) § Earth went through periods of cooling (“Snowball Earth”) and warming • Earth began cycles of glacial and interglacial periods ~3 million years ago

Earth’s Temperature Solar/Radiant Sun Energy Solar/Radiant Energy

Earth’s Temperature Sun Solar Energy Radiative Cooling

Earth’s Temperature Sun Solar Energy Radiative Cooling

Earth’s Temperature Sun Solar Energy Radiative Cooling

Sun Greenhouse Effect

Earth’s Atmospheric Gases Nitrogen (N 2) 99% Oxygen (O 2) Non. Greenhouse Gases Water (H 2 O) Carbon Dioxide (CO 2) Methane (CH 4) 1% Greenhouse Gases

Sun Runaway Greenhouse Effect • 97% carbon dioxide • 3% nitrogen • Water & sulfuric acid clouds • Temperature: 860°F Venus

Carbon Dioxide

CO 2 (ppm) 420 Carbon Dioxide Levels CO 2 (ppm) 370 320 Muana Loa Readings CO 2 Levels Since 1958 370 350 330 310 40 30 20 10 0 270 220 Dome Concordia 170 600000 Vostok Ice Core 400000 200000 Time (YBP) 0

Carbon (109 metric tons) Worldwide Carbon Emissions 8 7 6 5 Total Liquid fuel Solid fuel Gas fuel 4 3 2 1 0 1750 1800 1850 1900 Year 1950 2000

Carbon (109 metric tons) 8 Annual Carbon Emissions 6 Annual carbon emissions Atmospheric CO 2 average 4 2 0 1955 1965 1975 1985 Year 1995 2005

Future Carbon Dioxide Levels • Increasing CO 2 emissions, especially in China and developing countries • Likely to double within 150 years: § Increased coal usage § Increased natural gas usage § Decreased petroleum usage (increased cost and decreasing supply)

Kyoto Protocol • Adopted in 1997 • Cut CO 2 emissions by 5% from 1990 levels for 2008 -2012 • Symbolic only, since cuts will not significantly impact global warming

Past Temperatures

D Mean Temperature (°C) 0. 8 Recorded Worldwide Temperatures 0. 6 0. 4 0. 2 Decreasing Flat 0. 0 -0. 2 -0. 4 -0. 6 1880 1900 1920 1940 Year 1960 1980 2000

Historic Los Angeles Temperature (°C) 22 Annual Temperatures 25 Summer Temperatures 17 21 24 16 20 23 15 19 22 14 18 21 13 17 20 12 16 19 11 Winter Temperatures 15 18 10 1880 1900 1920 1940 1960 1980 2000 Year

2007 Temperature Changes Compared to 1951 -1980 -3 -2. 5 -1 -. 5 -. 1 . 5 1 1. 5 2. 5 3. 4

Past Temperatures Measurement • Proxy – a method that approximates a particular measurement (e. g. , temperature) § § § Ice cores Pollen records Plant macrofossils Sr/Ca isotope data Oxygen isotopes from speleothem calcite (stalactites and stalagmites)

Temperature History of the Earth • Little ice age (1400 -1840) – 1°C cooler • Medieval warm period (800 -1300) – 1°C warmer than today • Cool/warm cycles occur ~1, 500 years • Affect mostly Northeastern U. S. and North Atlantic • Mostly due to changes in thermohaline circulation • Dramatic shutdown of thermohaline circulation occurred 8, 200 years ago as a large lake in Canada flooded the North Atlantic

Main Ocean Currents Adapted from IPCC SYR Figure 4 -2

Temperature History of the Earth • For the past 3 million years, the earth has been experiencing ~100, 000 year long cycles of glaciation followed by ~10, 000 year long interglacial periods • These climate periods are largely the result of cycles in the earth’s orbit – precession, obliquity, and eccentricity

Orbital Parameters: Precession Apehelion Perihelion

Orbital Parameters: Obliquity 22. 5° 24. 5°

Orbital Parameters: Eccentricity Maximum: 0. 061 Minimum: 0. 005 Apehelion Perihelion Not. Scale! To to scale!

Orbital Parameters & Earth’s Climate Precession (22 ky) Obliquity (41 ky) Eccentricity (100 ky) Temperature 1000 900 800 700 600 500 400 300 200 100 0 Age (kya)

Temperature History of the Earth • For the past 3 million years, the earth has been experiencing ~100, 000 year long cycles of glaciation followed by ~10, 000 year long interglacial periods • Last ice age began to thaw 15, 000 years ago, but was interrupted by the “Younger Dryas” event 12, 900 years ago

Temperature (°C) -25 -30 0. 35 Younger Dryas 0. 30 Medieval Warm -35 -40 Ice Age 0. 25 Little Ice Age 0. 20 -45 0. 15 -50 0. 10 -55 20 15 10 Age (kya) 5 0. 05 0 Snow Accumulation (m/yr) Younger Dryas Event

-8. 0 Younger Dryas -7. 5 d 18 O (China) -7. 0 -6. 5 -6. 0 -5. 5 -5. 0 -4. 5 -4. 0 16 15 14 13 12 11 Age (kya) -34 -35 -36 -37 -38 -39 -40 -41 -42 -43 -44 10 d 18 O (Greenland) Younger Dryas Event

Temperature History of the Earth Middle Pliocene (3. 15 to 2. 85 million ya) • Temperatures: 2°C higher than today. § 20°C higher at high latitudes § 1°C higher at the Equator • Sea levels were 100 ft higher • Causes § CO 2 levels that were 100 ppm higher § Increased thermohaline circulation

Temperature History of the Earth Eocene (41 million years ago) • Opening of the Drake Passage (between South America and Antarctica). • Increased ocean current exchange § Strong global cooling § First permanent glaciation of Antarctica ~34 million years ago

Temperature History of the Earth Paleocene Thermal Maximum (55 mya) • Sea surface temperatures rose 5 -8°C • Causes § Increased volcanism § Rapid release of methane from the oceans

Temperature History of the Earth Mid-Cretaceous (120 -90 mya) • Much warmer • Breadfruit trees grew in Greenland • Causes § Different ocean currents (continental arrangement) § higher CO 2 levels (at least 2 to 4 times higher than today, up to 1200 ppm)

Recent Temperature Changes

Temperature Change (°C) “Hockey Stick” Controversey 0. 6 0. 4 Direct temperature measurements Mann et al. 1999 0. 2 0 -0. 2 -0. 4 -0. 6 -0. 8 1000 1200 1400 1600 Year 1800 2000

Temperature Change (°C) Is the Hockey Stick Correct? 2 Mann et al. 1999 Esper et al. 2002 1 0 -1 -2 800 1000 1200 1400 Year 1600 1800 2000

Is the Hockey Stick Correct? Temperature Change (°C) 0. 4 0. 2 0. 0 -0. 2 -0. 4 -0. 6 Mann et al. 1999 Esper et al. 2002 Moberg et al. 2005 Mann et al. 2008 -0. 8 -1. 0 -1. 2 0 400 800 1200 Year 1600 2000

Temperature Change (°C) U. S. National Academy of Sciences: June 2006 0. 4 “ 2: 1 chance of being right” “high level of confidence” 0. 2 0 -0. 2 -0. 4 -0. 6 -0. 8 1000 1200 1400 1600 Year 1800 2000

Atmospheric Temperatures Temperature Cgange (°C) 0. 8 Troposphere 0. 6 1. 5 Stratosphere 1. 0 0. 4 0. 2 0. 5 0. 0 -0. 2 -0. 5 -0. 4 -0. 6 1980 1990 Year 2000 -1. 0 1980 1990 Year 2000

CO 2 (ppm) Antarctica 370 320 270 220 170 600000 400000 200000 Time (YBP) 31 30 29 28 27 26 025 SST (°C) Tropical Pacific CO 2 Concentration Vs. Temperature

Consequences of Global Warming

Temperature Change (°C) Global Warming Primarily Impacts the Northern Hemisphere 1. 0 Northern vs. Southern Latitude 0. 8 0. 6 Northern Hemisphere Southern Hemisphere Land vs. Ocean Land Ocean 0. 4 0. 2 0. 0 -0. 2 -0. 4 -0. 6 1920 1960 Year 2000

2007 Temperature Changes Compared to 1951 -1980 -3 -2. 5 -1 -. 5 -. 1 . 5 1 1. 5 2. 5 3. 4

Ice Sheets Melting? • GRACE (gravity measured by satellite) found melting of Antarctica equivalent to sea level rise of 0. 4 mm/year (2 in/century) • Zwally, 2005 (satellite radar altimetry) § confirmed Antarctica melting § Greenland ice melting on exterior, accumulating inland (higher precipitation)

Melting Glaciers – Mt. Kilimanjaro

Changes in Antarctica Ice Mass 1000 Ice Mass (km 3) 800 600 400 200 0 -200 -400 -600 2003 2004 Year 2005

Rise in Sea Levels? • Present rate is 1. 8 ± 0. 3 mm/yr (7. 4 in/century) • Accelerating at a rate of 0. 013 ± 0. 006 mm/yr 2 • If acceleration continues, could result in 12 in/century sea level rise • Scenarios claiming 1 meter or more rise are unrealistic

Relative Sea Level (cm) Global Temperature Change 20 Changing Sea Levels 10 0 -10 -20 1700 Amsterdam, Netherlands Brest, France Swinoujscie, Poland 1750 1800 1850 1900 1950 2000 Adapted from IPCC SYR Figure 2 -5

20 31 0 30 -20 29 -40 28 -60 -80 27 -100 26 -120 25 450 400 350 300 250 200 150 100 50 Time (KYBP) 0 SST (°C) Tropical Pacific Sea Level (m) Sea Levels for 450, 000 Years

SST/SPDI (meters 3/sec 2) 15 Increase in Hurricanes? Data Unreliable • Two studies showed the total number of hurricanes has not changed 10 • However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones) • 5 Probably due to higher sea surface August-October temperatures (more Scaled energy) Sea-Surface Temperature • Difficult to know if this trend will Storm Adjusted Atlantic Power Dissipation Index continue 0 1860 1880 1900 1920 1940 1960 1980 2000 2020

How Much Temperature Increase? • Some models propose up to 9°C increase this century • Two studies put the minimum at 1. 5°C and maximum at 4. 5°C or 6. 2°C • Another study puts the minimum at 2. 5°C

Wildlife Effects • Polar Bears § Require pack ice to live § Might eventually go extinct in the wild • Sea turtles § Breed on the same islands as their birth § Could go extinct on some islands as beaches are flooded • Other species may go extinct as rainfall patterns change throughout the world

Effect on Humans • Fewer deaths from cold, more from heat • Decreased thermohaline circulation § Cooler temperatures in North Atlantic • CO 2 fertilization effect • Precipitation changes § Droughts and famine (some areas) § Expanded arable land in Canada, Soviet Union

Potential Worldwide Precipitation Changes -50 -20 -10 -5 5 10 20 50

Drought in Africa Lake Faguibine Lake Chad

Cost (Trillons U. S. Dollars) 1800 1600 1400 1200 1000 800 600 400 200 0 Cost to Stabilize CO 2 Concentrations 450 550 650 Carbon Dioxide (ppm) 750

Possible Solutions to Global Warming

Mitigation of Global Warming • Conservation § Reduce energy needs § Recycling • Alternate energy sources § § § Nuclear Wind Geothermal Hydroelectric Solar Fusion?

Storage of CO 2 in Geological Formations 1. 2. 3. 4. Depleted oil and gas reservoirs CO 2 in enhanced oil and gas recovery Deep saline formations – (a) offshore (b) onshore CO 2 in enhanced coal bed methane recovery 3 a 3 b 1 4 2 Adapted from IPCC SRCCS Figure TS-7

Conclusions • Global warming is happening • Most warming is probably the result of human activities • There will be positive and negative (mostly) repercussions from global warming • The costs to mitigate global warming will be high – better spent elsewhere?