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Tragedy of the Commons Commons resources that are shared or collectively owned Tragedy of the Commons a situation in which multiple individuals, acting independently, and solely and rationally consulting their own self-interest, will ultimately deplete a shared limited resource even when it is clear that it is not in anyone's long-term interest for this to happen. Read this brief essay by Garrett Hardinbrief essay Think about how the atmosphere is a commons and air pollution, global warming, represent tragedies of the commons. Discuss in the Forum Now we will look in-depth at one global issue dealing with the atmosphere: Global Warming 2

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Global Warming Whats heating the Earth? Starts with solar radiation Atmosphere lets most light in Some reflected, some absorbed by ground Video: Climate Change 101 with Bill Nye the Science GuyClimate Change 101 with Bill Nye the Science Guy

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The Greenhouse Effect Step 1: Earths surface absorbs short- wavelength solar radiation (visible light), and becomes warmer Step 2: Earths surface re- radiates the energy as long-wavelength radiation (heat)

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The Greenhouse Effect (continued) Step 3: Molecules of certain gases in the atmosphere absorb some of the heat, and the atmosphere becomes warmer. Greenhouse gases (GHG): CO 2, water, methane, others

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Greenhouse Effect, CO2, and Global Warming The Greenhouse Effect Natural phenomenon that keeps us comfortable on Earth. CO2 is the most important greenhouse gas If less CO2 in atmosphere then temperature and climate are cooler If more CO2 in atmosphere then temperature and climate are warmer Atmospheric CO2 levels today are about 393 parts per million (ppm) or 0.0393% This may not seem like a lot, but its the highest in AT LEAST 800,000 years! Check out these two articles Ice Core Data Show Current CO2 Levels Highest in 800,000 Years UCLA Researchers Find CO2 at Highest Levels in 15 Million Years 6

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How Do We Know What Prehistoric CO2 Levels Were? We examine ice core samples 8

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Ice Core Analysis 9

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Ice Core Analysis (continued) Most ice in glaciers and at the poles originates from snowfall Seasonal variation in snowfall causes layering in the ice This image clearly shows the annual layers in a core sample The deeper we drill, the older the ice we extract Since the ice originated as snow, bubbles of air are trapped inside The air bubbles are samples of the atmosphere from 1000s of years ago By analyzing the chemical composition of the ice and air samples, we can determine the approximate temperature and the amount of CO2 present in the atmosphere 10

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Ice Core Analysis (continued) Examine the Vostok ice core graph on the previous page It covers a 400,000 year period ending in 1950 CE (AD) What is the apparent relationship between atmospheric CO2 and temperature? From previous slides, what is the atmospheric CO2 level in 2010? What could that mean for global temperatures? Ice core data from the North and South Poles as well as data from near the equator in Hawaii show rapid rise in atmospheric CO2 12

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Where does CO 2 come from? 13

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CO2 and Human Activity 14 This box is a zoomed in view of the past 1000 years It suggests that human activity has caused the dramatic increase in CO2 levels Causes: burning of fossil fuels, wood,; destruction of carbon sinks (ex: trees and algae that absorb carbon) The graph on the next slide shows an even stronger correlation between people and CO2

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Human Activity and CO2 15

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Evidence the Earth is Warming 16

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What about Ohio? (Data from US Historical Climatology Network) 17

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What about other stations? Pacific Coast 18

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Pacific Northwest 19

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Desert Southwest (Note this is maximum not mean) 20

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Rocky Mountains 21

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Central Great Plains 22

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Southeast 23

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Northeast 24

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With respect to average temperature 1940-1980 25

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Global average temperature 1855-2002 26

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Look at the colored bars representing average temperature changes per decade over the past 150 years. Note how the rate of temperature increase is increasing. I.e., were getting warmer faster. 27

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Some of the Effects of Global Warming 28

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Snow Cover on Mt. Kilimanjaro, Tanzania 1993 and 2000 Check out this brief video for more on Kilimanjaros glaciers. National Geographic on Kilimanjaro Think about it: 1.What is occurring on Kilimanjaro? 2.Where else in the world do you think this is happening? 3.How important is it? 4.What will be the impact on humans, wildlife, agriculture,? 30

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Arctic Sea Ice Coverage, 1979-2007 Note the rapid decrease in sea ice coverage. As global warming causes reductions in sea ice, the lack of sea ice causes further global warming. This is because ice is more reflective than open ocean. It reflects sunlight and heat back into space. As it vanishes, more sunlight is absorbed by the seas and the warmer they become. The warmer the seas, the more ice melts

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Rising Oceans Sea ice melt does not affect sea level since the ice that melts was already displacing water However, melt runoff from glaciers and ice cover on land (Antarctica, Greenland,) does cause sea level rise 32

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Additional Effects Loss of habitat and extinction of species Extreme weather events Changes in precipitation patterns Shifts in agricultural zones Expansion of tropical disease ranges Flooding of low-lying areas 33

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Climate Change Regime Inter-governmental Panel on Climate Change (IPCC) Leading UN agency that researches and advises on climate change National Oceanic and Atmospheric Administration (NOAA) Key US agency dealing with climate change Kyoto Protocol, 1997 Legally binding targets for greenhouse gas (GHG) reductions Went into effect in 2005 Some see it as a crucial step toward controlling GHG Others see it as a failure. USA signed but never ratified Kyoto Copenhagen Accord, 2009 New International agreement to reduce GHG Pros: all countries now recognize global warming as one of the greatest challenges of our time Cons: very weak, not legally-binding, strong disagreements between MDCs and LDCs 34

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Just so you know where we stand 35

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Climate is changing. How can we adapt? Watch this TED Talk by Vicki ArroyoVicki Arroyo 10 minute video: Lets Prepare for Our New Climate Write a 4-5 paragraph summary & analysis Submit under Assignments on Isidore 37

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Other Atmospheric Issues Ozone Depletion Has NOTHING directly to do with global warming Certain chemicals (Ozone depleting substancesODS) interact with and destroy ozone (O3) in the stratosphere Common ODS: chlorofluorocarbon (CFC) from aerosol cans, refrigerators, solvents,... ; halon from fire extinguishers; nitrous oxide; and others Lower levels of stratospheric ozone allow in too much ultraviolet (UV) radiation from the sun, which causes blindness, skin cancer, and, potentially, eradication of all life on earth Montreal Protocol, 1987 Agreement to halt the production of CFC. Most successful international agreement of ALL TIME Ozone layer is currently repairing itself As long as countries follow Montreal Protocol, the problem should be fixed 38

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Other Atmospheric Issues Acid Rain A global issue because it is often transboundary (crosses borders) Primarily from burning of high sulfur content coal in power plants for electricity generation Sulfur dioxide (SO2) in power plant emissions combines with water vapor (H2O) in the atmosphere to produce H2SO4 Sulfuric Acid Adverse effects Soil and bodies of water become more acidic, killing microbes, insects, fish, and plants Damages agriculture, ecosystems, forests, buildings, and has been linked to some cancers and other diseases in humans No UN agreements on acid rain since, unlike global warming and ozone depletion, it is not a global, but a regional problem 39

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Acronyms to Know Find them in the chapter, power point, or the list of acronyms on p.329 in the text The acronyms of Modules 7 & 8 are combined for the Acronym 5 Assignment Once you know what each acronym stands for, go to Assignments and complete the Acronym 5 assignment CFC CO2 GHG IPCC NOAA ODS 40

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AssignmentsDue 7/27 News Summary and Analysis on Climate Change Vicki Arroyo TED Talk essay Acronym 5 Assignment Module 8 Discussion in Forum 41