Our atmosphere Earth s atmosphere the layer of

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Our atmosphere Earth’s atmosphere = the layer of gases that surround the planet Very thin layer, relative to size of planet Atmosphere: • Absorbs solar radiation • Burns up meteors • Transports and recycles water, and other chemicals • Moderates climate Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Atmospheric layers Atmosphere consists of several layers: Troposphere = Bottom layer, at Earth’s surface. 11 km high. Temperature decreases with altitude. Stratosphere = Next layer up (11– 50 km). Temperature increases with altitude. Contains “ozone layer. ” Mesosphere = Third layer up (50– 90 km). Temperature decreases with altitude. Thermosphere = Top layer (90– 500 km). Very thin air; mostly lightweight elements. Very hot. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Atmospheric layers Temperature and other characteristics vary with altitude. Ozone layer Tropopause marks boundary between troposphere and stratosphere. Layers don’t mix. Figure 11. 3 Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Ozone layer Not really a layer, but a region of higher-than-normal ozone concentrations (which are still very low) ~17– 30 km altitude Ozone = O 3—molecule of 3 oxygen atoms Absorbs ultraviolet (UV) radiation from sun, protecting organisms on surface from radiation damage Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Create Atmosphere Quadrafold One side for each layer: • Title • Vertical range of layer • Temperature change according to elevation • Special characteristic of that layer • Drawing which helps you remember the layer name with its characteristics Pg 480 in your text will help you Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Stratospheric ozone depletion Ozone in troposphere = harmful pollutant Ozone in stratosphere = beneficial layer protecting us from UV radiation “Ozone layer”— ~ 12 parts per million in lower stratosphere—is enough to absorb UV and protect us. But in the 1960 s scientists noticed ozone concentrations were dropping. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Stratospheric ozone depletion In 1974, Sherwood Rowland Mario Molina pegged the blame on chlorofluorocarbons (CFCs). They won the Nobel Prize for this scientific detective work. CFCs = human-made molecules in which hydrogens of hydrocarbons are replaced by chlorine and fluorine atoms Mass-produced by industry, in refrigerants and consumer products like aerosol sprays Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Stratospheric ozone depletion In 1985, the “ozone hole” was detected over Antarctica. Ozone levels had declined 40– 60% over the previous decade. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 17 a

Stratospheric ozone depletion Scientists worried about the effects of extra cancer-causing UV on people, organisms, ecosystems. The ozone hole (blue) reached its greatest extent in September 2000 (satellite imagery). Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 17 b

Stratospheric ozone depletion In 1987, over 180 nations signed the Montreal Protocol, which restricted CFC production globally. Follow-up agreements strengthened the pact. Today CFC levels are down, and stratospheric ozone is starting to recover. The Montreal Protocol is one of the biggest environmental success stories of our time. We have apparently avoided a major environmental problem. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Stratospheric ozone depletion Reasons for success of the Montreal Protocol: • Government and industry cooperated on finding solutions (cheap replacement technologies for CFCs), so battles typical to environmental debates were minimized. • Protocol was implemented with “adaptive management”—ability to fine-tune actions as time goes on, in response to new data or conditions. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Weather and climate Weather = local physical properties of the troposphere, including temperature, pressure, humidity, cloudiness, wind Climate = pattern of atmospheric conditions across large geographic regions over long periods of time (seasons, years, millennia) “Climate is what we expect; weather is what we get. ” –Mark Twain Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Global climate patterns … result from differential heating of Earth’s surface. And from gigantic convection currents called Hadley cells, Ferrel cells, and polar cells Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Global convection currents Hadley cells: air rises at equator, falls at 30º latitude. Ferrel cells: air falls at 30º, rises at 60º. Polar cells: air rises at 60º, falls at 90º. Figure 11. 10 a Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Global wind patterns These 3 types of cells also influence wind patterns near the ground. The Coriolis effect (planet’s rotation causes land at the equator to spin more quickly than temperate land) causes north-south winds to appear to be deflected, and to curve. Figure 11. 10 b Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Outdoor air pollution Air pollution = material added to the atmosphere that can affect climate and harm organisms, including humans Air pollution can come from human-made chemicals and causes, but the majority is from natural sources. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Artificial sources of air pollution Human-caused air pollution includes: Point sources = specific spots where large amounts of pollution are discharged (factory smokestacks) Non-point sources = diffuse, often made up of many small sources (charcoal fires from thousands of homes) Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Artificial sources of air pollution Human-caused air pollution includes: Primary pollutants = emitted into troposphere in a directly harmful form (soot, carbon monoxide) Secondary pollutants = produced via reaction of substances added to the atmosphere with chemicals already present in the atmosphere (ozone in troposphere) Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Six “criteria pollutants” The EPA closely tracks 6 major types of pollutants: • Carbon monoxide (CO) • Sulfur dioxide (SO 2) • Nitrogen dioxide (NO 2) • Tropospheric ozone (O 3) • Lead (Pb) • Particulate matter Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Six “criteria pollutants” Emissions of all of these, especially lead and carbon monoxide, have substantially declined since 1970. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 12

CO / SO 2 / NO 2 Carbon monoxide (CO) = colorless, odorless gas. From vehicle exhaust and other sources. Dangerous; prevents oxygen uptake. Sulfur dioxide (SO 2) = colorless gas. From coal burning for electricity and industry. Contributes to acid precipitation. Nitrogen dioxide (NO 2) = foul-smelling red gas. From vehicle exhaust, industry, electricity. Contributes to smog and acid precipitation. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

O 3 / Pb / particulate matter Tropospheric ozone (O 3) = colorless gas. Secondary pollutant from sunlight, heat, nitrogen oxides (NOx), and Ccontaining chemicals. Contributes to smog; harmful to living tissues. Lead (Pb) = metal in atmosphere as particulate. From gasoline additive, phased out in 1980 s. Diverse health impacts, all bad. Particulate matter = any solid (or liquid) particles small enough to be carried aloft in air. Dust, soot, sulfates, nitrates. Causes respiratory damage. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Success against lead A major source of lead, an additive in gasoline, was banned when its health effects became obvious. This came about through cooperative action among government, industry, scientists, citizens. Lead emissions in the U. S. dropped 93% between 1982 and 2001. Huge victory for public health Example of what can be done Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Volatile organic compounds “VOCs” are regulated by many governments. Large group of potentially harmful carboncontaining chemicals used in industrial processes Hydrocarbons are one example. About half are human-made, half natural. VOCs contribute to smog, produce secondary pollutants. Most of the 188 pollutants identified by 1970 Clean Air Act are VOCs. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Industrial smog Smog from industrial pollution, fossil-fuel combustion The kind that blanketed London in 1952 “Gray air smog” Contains soot, sulfur, CO 2… Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Industrial smog The U. S. had its own “killer smog” from industrial pollution. Shown is Donora, Pennsylvania, in 1948, at midday. Subsequent demand for legislation against pollution made U. S. air much cleaner. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 14 b

Industrial smog Chemistry of industrial smog: • Burning sulfur-rich oil or coal creates SO 2, SO 3, sulfuric acid, ammonium sulfate. • Carbon leads to CO 2 and CO. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 14 a

Photochemical smog Smog from reaction of sunlight with pollutants The kind that blankets so many American cities today “Brown air smog” Contains tropospheric ozone, NO 2, VOCs, 100 more… Hot sunny days in urban areas create perfect conditions. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Photochemical smog Mexico City and many of the world’s cities suffer from the brownish haze of photochemical smog. Inversion layers and mountains can trap smog over certain cities. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 15 a

Photochemical smog Chemistry of photochemical smog: Nitric oxide starts a chain reaction. Reaction with sunlight, water vapor, hydrocarbons, results in over 100 secondary pollutants. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 15 b

Acid precipitation Acid rain, acid fog, acid snow Caused by reaction of pollutants like SO 2 and NO with water, oxygen, and oxidants to form acids that fall to surface in precipitation: sulfuric acid (H 2 SO 4) nitric acid (HNO 3) Like ozone depletion, this is another transboundary pollution issue, i. e. , it crosses political boundaries. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Acid precipitation is created by reactions in the atmosphere, and can fall many miles from where pollution originated. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 18

Acid precipitation Acidity varies geographically. (Orange = more acidic) Industrialized areas and regions downwind of them suffer most. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 11. 20

Acid precipitation This can be seen in data from New Hampshire’s Hubbard Brook Experimental Forest, where acid rain was first studied. p. H has increased (rain has become less acidic) since 1970, but is still much more acidic than normal rain. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings From The Science behind the Stories

Indoor air pollution Indoor air spaces generally have MORE pollution than outdoor spaces. U. S. citizens spend 90% of time indoors. Countless consumer products and synthetic chemicals kept indoors are used in our daily lives. UN estimate for world: 2. 2 million deaths/year from indoor air pollution 0. 5 million deaths/year from outdoor air pollution Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Indoor air pollution Burning fuel wood inside homes for cooking is a major source of indoor pollution in developing countries. In developed nations, the 2 biggest threats seem to be: cigarette smoke: lung cancer risk for smokers and those inhaling secondhand smoke radon: naturally occurring colorless, odorless gas. Radioactive, seeps up from ground and collects in buildings. Lung cancer risk. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Other indoor air pollution risks in the home Asbestos: in insulation, ceilings, walls. . . Lung disease, cancer Organisms: mold, mildew, dander, pollen, mites. . . Allergic reaction Carbon monoxide: poor ventilation, leaky furnace. . . CO poisoning Formaldehyde: paneling, furniture, carpets… irritation, cancer Lead: lead-based paint, drinking water… lead poisoning Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Other indoor air pollution risks in the home Pesticides: numerous ingredients… nervous system damage Soot and particulates: fireplaces, woodstove… respiratory problems VOCs: carpets, cleansers, paints, detergents… various effects Endocrine disruptors: fire retardants, pesticides… hormone problems Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Reducing indoor air pollution Buy and use low-toxicity products Provide good ventilation Limit exposure to plastics, treated wood, pesticides, cleansing fluids (put in garage, not home) Test home for radon Test drinking water for lead from pipes In developing world, provide ventilation, install cleanburning stoves, shift to gas Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Climate and climate change Climate = a region’s long-term pattern of atmospheric conditions, including temperature, precipitation, and other variables Global climate change = changes in climate on a worldwide scale Climate changes naturally, and always has, but the recent rapid warming of the planet and its change in atmospheric composition are widely thought due to human activities. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Radiation, atmosphere, and temperature Earth’s temperature depends on how much of the sun’s radiation enters the atmosphere and how much escapes back into space. Incoming solar radiation is: absorbed at the surface, or reflected by the atmosphere, or reflected by the surface into space. Infrared radiation emanating from Earth’s heated surface is: emitted into space, or absorbed by gases and kept in the atmosphere. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Radiation, atmosphere, and temperature Atmospheric gases that absorb the emanating radiation are greenhouse gases. By absorbing and re-emitting this radiation, they warm Earth’s atmosphere and surface, like a greenhouse. This popularly called the greenhouse effect. Rising concentrations of greenhouse gases in recent decades have resulted in global warming, an increase in Earth’s average surface temperature. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Carbon dioxide increase Due to: Burning of fossil fuels: We remove carbon-rich fuels from the ground where they have been stored for millions of years, and combust them in an instant, sending CO 2 into the atmosphere. Deforestation: Cutting down trees, removing vegetation from the land, decreases the sink for carbon. Some of the C in plants becomes CO 2 sent into the atmosphere. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change: Direct sampling Scientists have recorded carbon dioxide levels in the atmosphere directly since 1958, at a station in Hawaii. The data show a steady upward climb from 315 to 373 ppm. (The up and down zigzags are from regular wintersummer fluctuations. ) Figure 12. 6 Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Increase of other greenhouse gases Halocarbon gases (which include CFCs) are powerful greenhouse gases. But their effects are slowing due to the Montreal Protocol. Water vapor is the most abundant greenhouse gas. Its future changes, if any, remain uncertain. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Aerosols and cooling Aerosols (microscopic particles and droplets) in the atmosphere can: warm the climate (soot), or cool the climate (sulfates). Sulfate-rich volcanic eruptions can cool Earth temporarily. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Milankovitch cycles These 3 types of cycles also affect climate in the long term. Variation of Earth’s tilt Variation of Earth’s orbit Wobble of Earth’s axis Figure 12. 3 Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

El Niño and La Niña The best-known interactions between oceans and climate are El Niño and La Niña events. In normal conditions, winds push warm waters (red) to the western Pacific Ocean. This allows cold water to well up from the deep in the eastern Pacific. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings From The Science behind the Stories

El Niño and La Niña Normal conditions In an El Niño event, winds weaken, warm water sloshes to the east, and prevents the cold upwelling. La Niña is the opposite: Cold water spreads west. From The Science behind the Stories Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

El Niño and La Niña events influence rainfall and temperature globally, especially on each side of the Pacific. They cause droughts, floods, etc. They disrupt fisheries (e. g. , South American fisheries dependent on cold water upwelling). Key question: Is global climate change making these events more frequent? ? ? Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change How do scientists know all these things about what climate was like in the past, before we were here? A number of methods have been developed… Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change: Ice cores Ice caps and glaciers accumulated over thousands or millions of years. They contain bubbles of gas preserved from the time when each layer formed. Scientists drill cores and analyze the gas bubbles in each layer to see what the atmosphere was like at that time. Figure 12. 5 Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change: Pollen analysis Scientists also drill cores into the sediments of ancient lake beds. By identifying types of pollen grains in each layer, they can tell what types of plants were growing there at the time. From The Science behind the Stories Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change: Modeling To predict what will happen to climate in the future, scientists use climate models: Computer simulations that use known behavior of past climate to analyze how climate should behave as variables are changed. Coupled general circulation models (CGCMs) are models that combine, or couple, the effects of both atmosphere and ocean. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Studying climate change: Modeling Scientists test their models by entering real data from the past and seeing how well their model would have predicted past trends. They generally find: Models that incorporate only natural factors or only anthropogenic (human-caused) factors predict poorly. But models including both natural and anthropogenic factors predict very well. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Climate change and the IPCC report In 2001, the world’s climate scientists combined to produce the single most comprehensive and authoritative research summary on climate change: The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) The IPCC report summarized all scientific data on climate change, future predictions, and possible impacts. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Climate change and the IPCC report First, the IPCC report established that global temperature is rising. Direct measurements from thermometers since 1860 demonstrate this. Figure 12. 9 a Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Climate change and the IPCC report Proxy indicators of temperature (from pollen, ice cores, etc. ) were reviewed to establish ancient temperatures. These data (BLUE) overlapped with the direct temperature measurements (RED). (Gray shows statistical uncertainty. ) Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 12. 9 b

The IPCC report Some key findings on temperature: • Average temperature rose 0. 6°C (1. 0°F) during the 20 th century • 1990 s = warmest decade in past 1, 000 years • Northern hemisphere increase in 1900 s = most in 1, 000 years • Droughts increased in frequency and severity • Precipitation increased in north, but varied elsewhere Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

The IPCC report The IPCC also reported findings on physical changes: • Average sea level increased 10– 20 centimeters (4– 8 inches) during 20 th century • 2 weeks less ice cover on northern lakes and rivers • Arctic sea ice thinned 10– 40% in recent decades • Mountain glaciers melted back worldwide • Snow cover decreased 10% since satellite observations began • Growing season lengthened 1– 4 days each decade over the past 40 years Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

The IPCC report Biological changes were also found by the IPCC: • Geographic ranges of many species have shifted toward the poles and up in elevation. • In spring, plants are flowering earlier, birds migrating earlier, animals breeding earlier, and insects emerging earlier. • Coral reefs are “bleaching” more frequently. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

The IPCC report Lastly, the IPCC summarized economic impacts of climate change: • Economic losses due to weather and storms rose 10 fold over the past 40 years, partly due to climate change. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

The IPCC report: Causes of climate change The IPCC report reflected the predominant view of climate scientists: Human activities (especially fossil fuel use leading to rising greenhouse gas levels) are the main cause of climate change. However, the ways anthropogenic factors and natural factors interact is complex and not fully understood, so predicting the future is uncertain. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Climate change predictions: Impacts The IPCC and other groups have predicted future impacts of climate change. Predictions for the U. S. include: • Temperature will rise 3– 5°C (5– 9°F). • Droughts, floods, snowpack will decline, and water shortages will create diverse problems. • Temperature extremes will cause health problems; tropical diseases will move north into the U. S. • Sea level rise will flood coastal wetlands, real estate. • Ecosystems will be altered; some will disappear. • Agriculture and forestry may have mixed results. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Sea level rise Just as sea level rise could devastate the Maldives… … it could also inflict damage on the U. S. ’s coastal economies and ecosystems. A 51 -centimeters (20 inches) sea level rise would inundate wetlands and drylands on all U. S. coasts. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 12. 21

Central Case: Rising temperatures and seas may take the Maldives 80% of this island nation’s land is <1 m above water. Globally warming temperatures are causing sea levels to rise worldwide, endangering many island nations. They beg the U. S. and others to reduce fossil fuel use. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Predicted U. S. impacts: Heat index rises Two models show big increases in July heat index for the next 100 years, especially in the central and southeast U. S. (Heat index combines temperature and humidity. ) Figure 12. 13 a Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Debate over climate change Virtually all climate researchers agree that global climate is changing. Virtually all climate researchers agree that human fossil fuel use plays a large role in driving climate change. There is uncertainty over other possible factors that may be involved, and how they might interact with anthropogenic causes. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Debate over climate change There is much debate over what to do about climate change. • Would costs of reducing greenhouse gas emissions outweigh costs of climate change? • Should industrialized nations bear more responsibility for reducing emissions, or should all nations share equally? • Should emissions reduction occur voluntarily, or through legal, political, or economic pressure? • How should we allocate funds to reduce emissions and deal with climate change impacts? Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Viewpoints: Global climate change Paul Craig “Global warming’s threat is real, huge, and imminent. The next two decades will be a time of decision making. The evidence of global warming is strong and will get stronger. We lack good implementation plans, but these are coming. ” Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Bob Williams “Weaning humanity from an economy based on fossil fuels to one based on non-carbon energy could wreak worldwide economic devastation the costs of which, in human and environmental terms, could outweigh those of projected global climate change. ” From Viewpoints

Emissions reduction: More efficient generation and usage Electricity generation is the biggest source of greenhouse gas emissions in the U. S. So solutions include: • Improved technology at plants • Cleaner-burning coal • Energy conservation by consumers Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 12. 15

Emissions reductions: Biking and walking Reducing automobile usage would also lower emissions. More and more people are choosing to live closer in and bike or walk to work. If Americans used public transportation at the rate Europeans do, the U. S. would no longer need Saudi Arabian oil. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 12. 19

Emissions reductions: International treaties 1992: UN Framework Convention on Climate Change Voluntary approach Nations were asked to cut emissions Failed 1997: Kyoto Protocol drafted: By 2012 reduce 6 greenhouse gases to below 1990 levels Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Emissions reductions: Kyoto Protocol The Kyoto Protocol has been ratified by 111 nations so far. The U. S. is not one of them. If Russia signs the pact, that will be enough to make it binding. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Emissions reductions: Kyoto Protocol The U. S. administration has said the treaty is unfair because it does not force developing nations like India and China to share in the burden of reducing emissions. Developing nations say industrialized nations like the U. S. created the problem, so they should be the ones to take the lead in cleaning it up. Supporters and opponents of Kyoto agree, however, that the treaty alone is not enough to turn around greenhouse gas production worldwide—it would just slow it down. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Emissions reductions: Precaution Because we do not know how bad climate change can make our lives, should we follow the precautionary principle and do everything we can to stop it now? Some say Yes: Some say No: Precaution will impede innovation and economic growth. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings The stakes are too high to gamble with our climate.

Conclusions: Challenges A better idea of natural climate variation in the past will help quantify the effects we are having now. Better climate models would help us predict what future impacts climate change will have. We need to find and encourage means to reduce emissions, preferably while not doing economic harm. We need international agreement to act against climate change. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Conclusions: Challenges Our vehicles, factories, and power plants emit large quantities of pollutants into our atmosphere. Photochemical smog plagues most cities. Industrial smog is a problem in developing world cities. CFCs have depleted much of Earth’s ozone layer. Acid precipitation is damaging ecosystems, architecture. Indoor air pollution is a major health threat. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Conclusions: Solutions Scientists continue to devise and carry out creative research to clarify natural ancient climate variation. Climate models are getting better, and predictions are becoming more detailed and reliable. Many means—conservation, technology, laws and incentives, consumer choices, renewable energy—exist to reduce emissions. Proponents must convince skeptics that these solutions will not mean economic harm. If the U. S. refuses to ratify the Kyoto Protocol, more strict treaties will be necessary in the future. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

Conclusions: Solutions In developed nations, many outdoor air pollutants have been reduced, some markedly, by legislation and technology. Cleaner-running cars could reduce photochemical smog. Regulations on industry and improved technology have greatly decreased industrial smog in the developed world. The Montreal Protocol has halted ozone depletion. Acid precipitation has stopped getting worse, thanks to legislation and emission-trading programs. Being aware of risks, and ventilating spaces, can greatly reduce dangers from indoor air pollution. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Greenhouse gases…? a. Absorb incoming ultraviolet radiation. b. Absorb infrared radiation released from Earth’s surface, which later warms Earth’s surface. c. Trap air in the troposphere and warm the Earth. d. Are translucent and glassy in appearance. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Movement of warm water eastward across the Pacific has been named…? a. Global climate change. b. The Milankovitch cycle. c. El Niño. d. La Niña. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Which conclusion was NOT reached by the IPCC Third Assessment Report? a. 1990 s were the warmest decade in the past 1, 000 years. b. Birds are migrating earlier in the spring. c. Sea level has decreased 20 centimeters in 100 years. d. Mountaintop glaciers are melting back worldwide. e. Climate change has caused economic losses. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review What health effects on people is climate change predicted to bring? a. Tropical diseases will move northward. b. Ozone pollution will increase in cities. c. Deaths from flooding will decrease. d. Both (a) and (b) will happen. e. Both (a) and (c) will happen. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Interpreting Graphs and Data Does having the blue data (ancient climate change) tell you anything about the red data (change since 1860)? a. No; they represent different time periods. b. Yes; it shows that the red increase is unusual. c. Yes; it shows that the red increase is not unusual. d. No; the blue and red data do not line up in the years they overlap. Figure 12. 9 b Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Viewpoints Should we take steps to avoid further climate change? a. Yes; it is a grave threat. b. Yes; we should follow the precautionary principle. c. No; it would cause too much economic harm. No; there may be just as many benefits from climate change as harmful effects. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Which atmospheric layer contains the gases we breathe and is responsible for the weather we experience? a. Troposphere b. Thermosphere c. Stratosphere d. Mesosphere e. Tropopause Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Which pollutant is involved when air pollution over cities interacts with sunlight, heat, oxygen, and other chemicals? a. Nitric oxide b. Nitrogen dioxide c. Tropospheric ozone d. All of the above Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Which statement about acid precipitation is FALSE? a. It alters soil chemistry. b. It damages buildings and statues. c. It can occur far from the source of its pollutants. d. It can kill trees. e. It did not occur until 1970. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Review Which are thought to be the most severe indoor air pollution threats in developed and developing nations, respectively? a. Indoor cooking fires; radon b. Pesticides; cigarette smoke c. Cigarette smoke; indoor cooking fires d. Industrial smog; carbon monoxide Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Weighing the Issues Look around your classroom or lecture hall. What changes might you suggest to improve indoor air quality? a. Open windows or otherwise increase ventilation. b. Remove certain products, materials, or items. c. Get tests run for radon, lead, or asbestos. Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings

QUESTION: Interpreting Graphs and Data Temperatures decrease with increasing altitude in the…? a. Stratosphere and thermosphere b. Troposphere and mesophere c. Stratosphere and tropopause Tropopause and ozone layer Figure 11. 3 Copyright © 2005 Pearson Education, Inc. , publishing as Benjamin Cummings