Global Warming 11/21/2011. Will Human-Induced Climate Change/Destroy the World?

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1 Global Warming Will Human-Induced Climate Change/Destroy the World? By: Rich Deem ( 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 7% 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) 1

2 History of Earth s Climate Life appeared ~3.8 billion years ago Photosynthesis began billion years ago Produced O 2 and removed CO 2 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 The Heat Equation Heat in = Heat out + Heat stored If Heat in = Heat out, then Heat stored = Zero Heat in < Heat out, then Earth would cool down Heat in > Heat out, then Earth would warm up Earth s Temperature Solar Sun Energy Solar Energy 2

3 Earth s Temperature Sun Solar Energy Radiative Cooling Sun Solar Earth s Temperature Energy Radiative Cooling Earth s Temperature Sun Solar Energy Radiative Cooling 3

4 Sun Greenhouse Effect Earth s Atmospheric Gases Nitrogen (N 2 ) Oxygen (O 2 ) 99% Non- Greenhouse Gases Water (H 2 O) Carbon Dioxide (CO 2 ) 1% Greenhouse Gases Methane (CH 4 ) Sun Runaway Greenhouse Effect 97% CO 2 3% N 2 Water & Sulfuric acid clouds Temperature: 86 F Venus 4

5 Carbon Dioxide CO 2 (ppm) Carbon Dioxide Levels CO 2 (ppm) Muana Loa Readings CO 2 Levels Since , Dome Concordia Vostok Ice Core 4, 2, Time (YBP) Carbon (1 9 metric tons) Worldwide Carbon Emissions Total Liquid fuel Solid fuel Gas fuel

6 Carbon (1 9 metric tons) Annual Carbon Emissions Annual carbon emissions Atmospheric CO 2 Atmospheric CO 2 average Future CO 2 Levels Increasing CO 2 emissions, especially in China and developing countries Likely to double within 15 years: Coal usage Increased natural gas usage Petroleum usage (due to cost and supply) Kyoto Protocol Adopted in 1997 Cut CO 2 emissions by 5% from 199 levels for Symbolic only, since cuts will not significantly impact global warming 6

7 Past Temperatures.8 Recorded Worldwide Temperatures Mean Temperature ( C) Flat Decreasing Historic Los Angeles Temperatures 22 Annual Temperatures 25 Summer Temperatures 17 Winter Temperatures Temperature ( C)

8 25 Temperature Changes Compared to 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 Temperature History of the Earth Little ice age (14-184) 1 C cooler Medieval warm period (8-13) +1 C warmer than today Cool/warm cycles occur ~1,5 years Affect mostly Northeastern U.S. and North Atlantic Mostly due to changes in thermohaline circulation Dramatic shutdown of thermohaline circulation occurred 8,2 years ago as a large lake in Canada flooded the North Atlantic 8

9 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 ~1, year long cycles of glaciation followed by ~1, 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 9

10 Orbital Parameters: Obliquity The earth s tilt goes from a minimum of 22.5 to a maximum of The current tilt is Orbital Parameters: Eccentricity Maximum:.61 Minimum:.5 Apehelion Perihelion Not To Scale! to scale! Orbital Parameters & Earth s Climate Precession (22 ky) Obliquity (41 ky) Eccentricity (1 ky) Temperature 1, Age (kya) 1

11 Temperature History of the Earth For the past 3 million years, the earth has been experiencing ~1, year long cycles of glaciation followed by ~1, year long interglacial periods Last ice age began to thaw 15, years ago, but was interrupted by the Younger Dryas event 12,9 years ago Temperature ( C) Younger Dryas Event Younger Dryas Ice Age 15 1 Age (kya) Medieval Warm Little Ice Age Snow Accumulation (m/yr) 18 O (China) Younger Dryas Event 15 Younger Dryas Age (kya) O (Greenland) 11

12 Temperature History of the Earth Middle Pliocene (3.15 to 2.85 million ya) Temperatures: 2 C higher than today. 2 C higher at high latitudes 1 C higher at the Equator Sea levels were 1 ft higher Causes CO 2 levels that were 1 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 12

13 Temperature History of the Earth Mid-Cretaceous (12-9 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 1,2 ppm) Recent Temperature Changes Hockey Stick Controversey Temperature Change ( C) Direct temperature measurements Mann et al

14 Temperature Change ( C) Is the Hockey Stick Correct? Mann et al Esper et al Temperature Change ( C) Is the Hockey Stick Correct? Mann et al Esper et al. 22 Moberg et al Temperature Change ( C).6.4 U.S. National Academy of Sciences: June 26 2:1 chance of being right high level of confidence

15 Temperature Cgange ( C) Atmospheric Temperatures Troposphere Stratosphere CO 2 Concentration Vs. Temperature CO 2 (ppm) Antarctica Time (YBP) SST ( C) Tropical Pacific Consequences of Global Warming 15

16 Temperature Change ( C) Global Warming Primarily Impacts the Northern Hemisphere Northern vs. Southern Latitude 1. Northern Hemisphere.8 Southern Hemisphere Land vs. Ocean Land Ocean Temperature Changes Compared to Ice Sheets Melting? GRACE (gravity measured by satellite) found melting of Antarctica equivalent to sea level rise of.4 mm/year (2 /century) Zwally, 25 (satellite radar altimetry) confirmed Antarctica melting Greenland ice melting on exterior, accumulating inland (higher precipitation) 16

17 Changes in Antarctica Ice Mass Ice Mass (km 3 ) Rise in Sea Levels? Present rate is 1.8 ±.3 mm/yr (7.4 in/century) Accelerating at a rate of.13 ±.6 mm/yr 2 If acceleration continues, could result in 12 /century sea level rise (scenarios claiming 1m or more rise are unrealistic) Relative Sea Level (cm) 2 1 Changing Sea Levels -1 Amsterdam, Netherlands Brest, France Swinoujscie, Poland Global Temperature Change Adapted from IPCC SYR Figure

18 Sea Level (m) Sea Levels for 45, s Time (KYBP) SST ( C) Tropical Pacific Increase in Hurricanes? Two studies showed the total number of hurricanes has not changed However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones) Probably due to higher sea surface and temperatures (more energy) Difficult to know if this trend will continue How Much Temperature Increase? Studies show a range between 1.5 C to 6.2 C Some propose up to 9 C increase this century 18

19 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 if 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 (increase crop yields) Precipitation changes Droughts and famine (in some areas) Expanded arable land in Canada, Soviet Union Potential Worldwide Precipitation Changes

20 Cost (Trillons U.S. Dollars) Cost to Stabilize CO 2 Concentrations Carbon Dioxide (ppm) Possible Solutions to Global Warming Mitigation of Global Warming Mitigation of Global Warming Conservation Reduce energy needs Recycling Alternate energy sources Nuclear Wind Geothermal Hydroelectric Solar Fusion? 2

21 Storage of CO 2 in Geological Formations 1. Depleted oil and gas reservoirs 2. CO 2 in enhanced oil and gas recovery 3. Deep saline formations (a) offshore (b) onshore 4. CO 2 in enhanced coal bed methane recovery 3b 1 3a 2 4 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? 21