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Lecture Outlines Chapter 18 Environment: The Science behind the Stories 4th Edition Withgott/Brennan © 2011 Pearson Education, Inc. This lecture will help you understand: • The Earth’s climate system • Human influences on the atmosphere and climate • Methods of climate research • Impacts of global climate change • Ways we can respond to climate change © 2011 Pearson Education, Inc. Central Case: Rising seas may flood the Maldives • Tourists think the Maldives Islands are a paradise • Rising seas due to global climate change could submerge them - Erode beaches, cause flooding - Damage coral reefs • Residents have evacuated the lowest-lying islands • Small nations are not the cause of climate change, yet they suffer © 2011 Pearson Education, Inc. What is climate change? • Climate change is the fastest-developing area of environmental science • Climate = an area’s long-term atmospheric conditions - Temperature, moisture, wind, precipitation, etc. - Weather = short-term conditions at localized sites • Global climate change = describes trends and variations in Earth’s climate - Temperature, precipitation, storm frequency • Global warming and climate change are not the same © 2011 Pearson Education, Inc. Global warming • Global warming = an increase in Earth’s average temperature - Only one aspect of climate change • Climate change and global warming refer to current trends - Earth’s climate has varied naturally through time • The current rapid climatic changes are due to humans - Fossil fuel combustion and deforestation • Understanding climate change requires understanding how our planet’s climate works © 2011 Pearson Education, Inc. The sun and atmosphere keep Earth warm • Four factors exert the most influence on climate • The sun = without it, Earth would be dark and frozen - Supplies most of Earth’s energy • The atmosphere = without it, Earth’s temperature would be much colder • The oceans = shape climate by storing and transporting heat and moisture • How Earth spins, tilts, and moves through space influence how climate varies over long periods of time © 2011 Pearson Education, Inc. The fate of solar radiation • The atmosphere, land, ice, and water absorb 70% of incoming solar radiation © 2011 Pearson Education, Inc. Greenhouse gases warm the lower atmosphere • As Earth’s surface absorbs solar radiation, the surface increases in temperature and emits infrared radiation • Greenhouse gases = atmospheric gases that absorb infrared radiation - Water vapor, ozone, carbon dioxide, nitrous oxide, methane, halocarbons [chlorofluorocarbons (CFCs)] • After absorbing radiation, greenhouse gases re-emit infrared energy, losing some energy to space • Greenhouse effect = energy that travels downward, warming the atmosphere and the planet’s surface © 2011 Pearson Education, Inc. The greenhouse effect is natural • Greenhouse gases have always been in the atmosphere • We are not worried about the natural greenhouse effect - Anthropogenic intensification is of concern • Global warming potential = the relative ability of one molecule of a greenhouse gas to contribute to warming - Expressed in relation to carbon dioxide (potential = 1) - Methane is 25 times as potent as carbon dioxide © 2011 Pearson Education, Inc. Carbon dioxide is of primary concern • It is not the most potent greenhouse gas, but it is extremely abundant - The major contributor to the greenhouse effects • CO2 exerts six times more impact than methane, nitrous oxide, and halocarbons combined • Deposition, partial decay, and compression of organic matter (mostly plants) in wetlands or marine areas led to formation of coal, oil, and natural gas - These deposits remained buried for millions of years © 2011 Pearson Education, Inc. What caused levels of CO2 to increase? • Burning fossil fuels transfer CO2 from lithospheric reservoirs into the atmosphere - The main reason atmospheric carbon dioxide concentrations have increased so dramatically • Deforestation contributes to rising atmospheric CO2 - Forests serve as reservoirs for carbon - Removing trees reduces the carbon dioxide absorbed from the atmosphere • Human activities increased atmospheric CO2 from 280 parts per million (ppm) to 389 ppm - The highest levels in more than 800,000 years © 2011 Pearson Education, Inc. Fluxes of carbon dioxide © 2011 Pearson Education, Inc. Other greenhouse gases add to warming • Methane = fossil fuels, livestock, landfills, crops (rice) - Levels have doubled since 1750 • Nitrous oxide = feedlots, chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers • Ozone levels have risen 36% due to photochemical smog • Halocarbon gases (CFCs) are declining due to the Montreal Protocol • Water vapor = the most abundant greenhouse gas - Contributes most to the natural greenhouse effect - Concentrations have not changed © 2011 Pearson Education, Inc. U.S. emissions of major greenhouse gases © 2011 Pearson Education, Inc. Feedback complicates our predictions • Tropospheric warming will transfer more water to the air - But the effects are uncertain • A positive feedback loop = more water vapor … more warming … more evaporation … more water vapor … • A negative feedback loop = more water vapor … more clouds … shade and cool Earth OR increase evaporation • Minor modifications of the atmosphere can lead to major effects on climate © 2011 Pearson Education, Inc. Most aerosols exert a cooling effect • Aerosols = microscopic droplets and particles - They have either a warming or a cooling effect • Soot (black carbon aerosols) causes warming by absorbing solar energy - But most tropospheric aerosols cool the atmosphere by reflecting the sun’s rays • Sulfate aerosols produced by fossil fuel combustion may slow global warming, at least in the short term - Volcanic eruptions reduce sunlight reaching Earth’s surface and cool the Earth © 2011 Pearson Education, Inc. Radiative forcing expresses change in energy • Radiative forcing = the amount of change in thermal energy that a given factor causes - Positive forcing warms the surface - Negative forcing cools it Earth is experiencing radiative forcing of 1.6 watts/m2 more than it is emitting to space – enough to alter the climate © 2011 Pearson Education, Inc. Milankovitch cycles influence climate • Milankovitch cycles = periodic changes in Earth’s rotation and orbit around the sun - Alter the way solar radiation is distributed over Earth • These cycles modify patterns of atmospheric heating - Triggering climate variation - For example, periods of cold glaciation and warm interglacial times © 2011 Pearson Education, Inc. Solar output and ocean absorption influence climate • Solar output = the sun varies in the radiation it emits - Variation in solar energy (e.g., solar flares) has not been great enough to change Earth’s temperature - Radiative forcing is 0.12 watts/m2 – much less than human causes • Ocean absorption = the ocean holds 50 times more carbon than the atmosphere - Slowing global warming but not preventing it • Warmer oceans absorb less CO2 - A positive feedback effect that accelerates warming © 2011 Pearson Education, Inc. Ocean circulation influences climate • Ocean circulation = ocean water exchanges heat with the atmosphere, - Currents move energy from place to place • The ocean’s thermohaline circulation system affects regional climates - Moving warm tropical water north, etc. - Greenland’s melting ice sheet will affect this flow • El Niño–Southern Oscillation (ENSO) - Shifts atmospheric pressure, sea surface temperature, ocean circulation in the tropical Pacific © 2011 Pearson Education, Inc. Direct measurements tell us about the present • We document daily fluctuations in weather - Precise thermometer measurements over the past 100 years • Measuring of ocean and atmospheric chemistry began in 1958 • Precise records of historical events - Droughts, etc. Atmospheric CO2 concentrations have increased from 315 ppm to 389 ppm © 2011 Pearson Education, Inc. Proxy indicators tell us about the past • Paleoclimate = climate of the geological past • Gives a baseline to compare to today’s climate • Proxy indicators = indirect evidence that serve as substitutes for direct measurements - Shed light on past climate - Ice caps, ice sheets, and glaciers hold clues to Earth’s climate history - Trapped bubbles in ice cores provide a timescale of: - Atmospheric composition, greenhouse gas concentrations, temperature trends - Snowfall, solar activity, and frequency of fires © 2011 Pearson Education, Inc. Ice cores from Antarctica • Ice cores let us go back in time 800,000 years - Reading Earth’s history across eight glacial cycles © 2011 Pearson Education, Inc. More proxy indicators • Cores in sediment beds preserve pollen grains and other plant remnants • Tree rings indicate age, precipitation, droughts, and fire history • In arid regions, packrats carry seeds and plants to their middens (dens) - Plant parts can be preserved for centuries • Researchers gather data on past ocean conditions from coral reefs • Scientists combine multiple records to get a global perspective © 2011 Pearson Education, Inc. Models help us predict the future • Climate models = programs combine what is known about: - Atmospheric and ocean circulation - Atmosphere–ocean interactions - Feedback mechanisms Models simulate climate processes to accurately predict climate change © 2011 Pearson Education, Inc. Results from three simulations • Figure (a) shows natural climate factors only - Volcanoes • Figure (b) shows only human factors - Greenhouse gas emissions • Figure (c) shows both factors © 2011 Pearson Education, Inc. Current and future trends and impacts • Evidence that climate conditions have changed since industrialization is everywhere - Fishermen in the Maldives, ranchers in Texas, homeowners in Florida, etc. • Scientific evidence that climate has changed is overwhelming and indisputable • Intergovernmental Panel on Climate Change (IPCC) was established in 1988 - Composed of hundreds of international scientists and government officials © 2011 Pearson Education, Inc. The IPCC’s fourth assessment report (2007) • The IPCC reports on the synthesis of scientific information concerning climate change - Global consensus of scientific climate research - Summarized thousands of studies • Documented observed trends in surface temperature, precipitation patterns, snow and ice cover, sea levels, storm intensity, etc. • Predicted impacts of current and future climate change on wildlife, ecosystems, and human societies • Discussed strategies to pursue in response to climate change © 2011 Pearson Education, Inc. The IPCC’s fourth assessment report (2007) © 2011 Pearson Education, Inc. Temperatures continue to increase • Average surface temperatures increased 0.74 °C since 1906 - Most of the increase occurred in the last few decades - Extremely hot days have increased - The 16 warmest years on record have been since 1990 © 2011 Pearson Education, Inc. The future will be hotter • In the next 20 years, temperatures will rise 0.4 °C • At the end of the 21st century, temperatures will be 1.8– 4.0 °C higher than today’s - We will have unusually hot days and heat waves • Polar areas will have the most intense warming • Sea surface temperatures will rise • Hurricanes and tropical storms will increase - In power and duration © 2011 Pearson Education, Inc. Temperatures will rise globally Projected increases in surface temperature for 2090–2099 relative to 1980–1999 © 2011 Pearson Education, Inc. Precipitation is changing, too • Some regions are receiving more precipitation than usual, and others are receiving less • Droughts have become more frequent and severe - Harming agriculture, promoting soil erosion, reducing water supplies, and triggering fires • Heavy rains contribute to flooding - Killing people, destroying homes, and inflicting billions of dollars in damage © 2011 Pearson Education, Inc. Projected changes in precipitation Precipitation will increase at high latitudes and decrease at low and middle latitudes © 2011 Pearson Education, Inc. Melting snow and ice • Mountaintop glaciers are disappearing - Glaciers on tropical mountaintops have disappeared - The remaining 26 of 150 glaciers in Glacier National Park will be gone by 2020 or 2030 - Reducing summertime water supplies • Melting of Greenland’s Arctic ice sheet is accelerating • Warmer water is melting Antarctic coastal ice shelves - Interior snow is increasing due to more precipitation • Melting ice exposes darker, less-reflective surfaces, which absorb more sunlight, causing more melting © 2011 Pearson Education, Inc. Worldwide, glaciers are melting rapidly • Nations are rushing to exploit underwater oil and mineral resources made available by newly opened shipping lanes • Permafrost (permanently frozen ground) is thawing - Destabilizing soil, buildings, etc. and releasing methane © 2011 Pearson Education, Inc. Rising sea levels • Runoff from melting glaciers and ice will cause sea levels to rise • As oceans warm, they expand - Leading to beach erosion, coastal floods, and intrusion of salt water into aquifers © 2011 Pearson Education, Inc. Coastal areas will flood An earthquake caused the 2004 tsunami (tidal wave) that killed 100 Maldives residents and caused $470 million in damages • Storm surge = temporary, localized rise in sea level - Caused by the high tides and winds of storms • Cities will be flooded - 53% of people in the U.S. live in coastal areas © 2011 Pearson Education, Inc. Rising sea levels will devastate coasts • 1 million acres of Louisiana’s wetlands are gone - Rising sea levels eat away vegetation - Dams upriver decrease siltation - Pollution from the Deepwater Horizon • Millions of people will be displaced from coastal areas © 2011 Pearson Education, Inc. Coral reefs are threatened • Coral reefs are habitat for food fish - Snorkeling and scuba diving sites for tourism • Warmer waters contribute to coral bleaching - Which kills corals • Increased CO2 is acidifying the ocean - Organisms can’t build their exoskeletons • Oceans have already decreased by 0.1 pH unit - Enough to kill most coral reefs © 2011 Pearson Education, Inc. Climate change affects organisms and ecosystems • Organisms are adapted to their environments - They are affected when those environments change • Global warming modifies temperature-dependent phenomena (e.g., timing of migration, breeding) • Animals and plants will move toward the poles or upward in elevation - 20–30% of species will be threatened with extinction - Rare species will be pushed out of preserves • Droughts, fire, and disease will decrease plant growth - Fewer plants means more CO2 in the atmosphere © 2011 Pearson Education, Inc. Animals and plants have nowhere to go • Animals and plants adopted to montane environments will be forced uphill until there is no place to go © 2011 Pearson Education, Inc. Climate change affects people • Societies are feeling the impacts of climate change • Agriculture: shortened growing seasons, decreased production, crops more susceptible to droughts - Increasing hunger • Forestry: increased fires, invasive species - Insect and disease outbreaks • Health: heat waves and stress can cause death - Respiratory ailments, expansion of tropical diseases - Disease and sanitation problems from flooding - Drowning from storms © 2011 Pearson Education, Inc. Heat waves will increase © 2011 Pearson Education, Inc. Climate change affects economics • Costs will outweigh benefits of climate change • It will widen the gap between rich and poor - Those with less wealth and technology will suffer most • External costs of damages will be $10–350/ton of carbon • It will cost 1–5% GDP on average globally - Poor nations will lose more than rich ones • The Stern Review predicts it will cost 5–20% of GDP by 2200 - Investing 1% of GDP now could avoid these costs © 2011 Pearson Education, Inc. Impacts will vary regionally • Where we live will determine how we experience the impacts of climate change • Temperature changes have been greatest in the Arctic - Melting ice sheets, thinning ice, increasing storms, etc. - Harder for people and polar bears to hunt • U.S. temperatures will continue rising - Plant communities will shift north and upward - More frequent extreme weather events • The southern U.S. will get drier, the northern wetter - Sea levels will rise and may be worse in the East © 2011 Pearson Education, Inc. Impacts of climate change The Arctic has suffered the most so far U.S. temperatures will continue to rise © 2011 Pearson Education, Inc. Impacts of climate change will vary © 2011 Pearson Education, Inc. The U.S. Global Change Research Program • In 2009, scientists reported and predicted: - Temperature increases - Worse droughts and flooding - Decreased crop yields - Water shortages - Health problems and diseases - Higher sea levels, beach erosion, destroyed wetlands - Drought, fire, and pests will change forests - More grasslands and deserts, fewer forests - Undermined Alaskan buildings and roads © 2011 Pearson Education, Inc. Predictions from two climate models By 2050, Illinois will have a climate like Missouri’s By 2090, it will have a climate like Louisiana’s © 2011 Pearson Education, Inc. Causes and consequences of climate change © 2011 Pearson Education, Inc. Are we responsible for climate change? • Scientists agree that increased greenhouse gases are causing global warming - Burning fossil fuels is increasing greenhouse gases • In 2005, scientists from 11 nations issued a joint statement urging political leaders to take action • There is a broad and clear scientific consensus that climate change is a pressing issue - But many people deny what is happening • People will admit the climate is changing - But doubt we are the cause © 2011 Pearson Education, Inc. The debate over climate change is over • Conservative think tanks and industry-sponsored scientists cast doubt on the scientific consensus • The news media tries to present two sides to an issue - But the sides’ arguments are not equally supported by evidence • Most Americans accept that fossil fuel consumption is changing the planet • Al Gore’s An Inconvenient Truth helped turn the tide - People who disliked his politics rejected his message © 2011 Pearson Education, Inc. “Climategate” • In 2009, a hacker illegally broke into a university’s computer in the U.K. • Private emails seemed to show questionable behavior by a few scientists in using data • Climate deniers accused the entire scientific establishment of wrongdoing and conspiracy - The story was widely told in the news • Investigations showed no evidence of wrongdoing - Media accounts misrepresented the email contents • These hacked emails do not call into question the vast array of results by thousands of scientists over decades © 2011 Pearson Education, Inc. Shall we pursue mitigation or adaptation? • Most people accept that our planet is changing - They are searching for solutions • Mitigation = pursue actions that reduce greenhouse gas emissions to lessen severity of future climate change - Energy efficiency, renewable energy, protecting soil, preventing deforestation • Adaptation = accept that climate change is happening - Pursue strategies to minimize its impacts on us - Seawalls, leaving the area, coping with drought, etc. • Both are necessary © 2011 Pearson Education, Inc. We need both adaptation and mitigation • Adaptation: even if we stopped all emissions, warming would continue • Mitigation: if we do nothing, we will be overwhelmed by climate changes The faster we reduce our emissions, the less we will alter the climate © 2011 Pearson Education, Inc. Electricity generation A coal-fired, electricity-generating power plant • The largest source of U.S. CO2 emissions - 70% of electricity comes from fossil fuels - Coal causes 50% of emissions • To reduce fossil fuel use: - Encourage conservation and efficiency - Switch to cleaner and renewable energy sources © 2011 Pearson Education, Inc. Conservation and efficiency • We can make lifestyle choices to reduce electricity use - Use fewer greenhouse-gas-producing appliances - Use electricity more efficiently • The EPA’s Energy Star Program rates appliances, lights, windows, etc. by their energy efficiency - Replace old appliances with efficient ones - Use compact fluorescent lights - Use efficient windows, ducts, insulation, heating and cooling systems © 2011 Pearson Education, Inc. Sources of electricity • We need to switch to clean energy sources - Nuclear power, biomass energy, solar, wind, etc. • We need to consider how we use fossil fuels - Switching from coal to natural gas cuts emissions 50% - Cogeneration produces fewer emissions • Carbon capture = removes CO2 from power plant emissions • Carbon sequestration (storage) = storing carbon underground where it will not seep out - Use depleted oil and gas deposits, salt mines, etc. - We can’t store enough CO2 to make a difference © 2011 Pearson Education, Inc. Transportation • 2nd largest source of U.S. greenhouse gases - Cars are inefficient • Ways to help: - More efficient cars - Hybrid or electric cars - Drive less and use public transportation - Live near your job, so you can bike or walk U.S. public transportation saves 4.2 billion gallons of gasoline and 37 million metric tons of CO2 emissions © 2011 Pearson Education, Inc. Conventional cars are inefficient © 2011 Pearson Education, Inc. We can reduce emissions in other ways • Agriculture: sustainable land management lets soil store more carbon - Reduce methane emissions from rice and cattle - Grow renewable biofuels • Forestry: reforest cleared land, preserve existing forests - Sustainable forestry practices • Waste management: treating wastewater - Generating electricity by incinerating waste - Recovering methane from landfills • Individuals can recycle, compost, reduce, or reuse goods © 2011 Pearson Education, Inc. We need to follow multiple strategies • There is no magic bullet for mitigating climate change • Most reductions can be achieved using current technology that we can use right away • Stabilization triangle = a portfolio of strategies, each one feasible in itself, that could stabilize CO2 emissions - Reducing 1 billion tons of carbon per year for 50 would eliminate one of the seven “wedges” • This approach is not enough – we need to reduce, not only stabilize, emissions © 2011 Pearson Education, Inc. Strategies to stabilize CO2 emissions 15 strategies could each take care of one wedge © 2011 Pearson Education, Inc. The FCCC • U.N. Framework Convention on Climate Change = a plan to reduce greenhouse gas emissions to 1990 levels by 2000 through a voluntary, nation-by-nation approach • By the late 1990s, it was clear that the voluntary approach would not succeed • Developing nations created a binding international treaty requiring emission reductions • The Kyoto Protocol = between 2008 and 2012, signatory nations must reduce emissions of six greenhouse gases to levels below those of 1990 © 2011 Pearson Education, Inc. The Kyoto Protocol tried to limit emissions • This treaty took effect in 2005 - After Russia became the 127th nation to ratify it • The United States will not ratify the Kyoto Protocol - It requires industrialized nations to reduce emissions - But it does not require industrializing nations (China and India) to reduce theirs • Other countries resent the U.S. because it emits 20% of the world’s greenhouse gases but won’t take action - In 2007, one delegate said, “If for some reason you are not willing to lead...please get out of the way.” © 2011 Pearson Education, Inc. The Copenhagen conference • The conference in 2009 tried to design a successor treaty to the Kyoto Protocol - Nations hoped the U.S., under President Obama, would participate in a full international agreement • Obama would not promise more than Congress had agreed to • In a last-minute deal, developed nations will help developing nations pay for mitigation and adaptation - Nations that reduce deforestation will be rewarded • Nothing is legally binding and no targets are set © 2011 Pearson Education, Inc. Will emissions cuts hurt the economy? • The U.S. Senate feels emissions reductions will hurt the economy • China and India also resist emissions cuts • Economic vitality does not need higher emissions - Germany cut emissions by 21%, the U.K. by 17% • Industrialized nations will gain from energy transitions - They invent, develop, and market new technologies • The future will belong to nations willing to develop new technologies and energy sources © 2011 Pearson Education, Inc. States and cities are advancing policies • The U.S. federal government is not taking action - State and local governments are • By 2010, 1,000 mayors signed the U.S. Mayors Climate Protection Agreement - To meet or beat Kyoto Protocol guidelines • California passed the Global Warming Solutions Act - To cut emissions 25% by 2020 • Regional Greenhouse Gas Initiative (RGGI) in 2007 - 10 northeastern states - Set up a cap-and-trade program © 2011 Pearson Education, Inc. Market mechanisms address climate change • Permit trading programs harness the economic efficiency of the free market to achieve policy goals - Businesses have flexibility in how they meet the goals • Polluters choose how to cut their emissions - They are given financial incentives to reduce them © 2011 Pearson Education, Inc. Cap-and-trade emissions trading programs • The approach of the Regional Greenhouse Gas Initiative: - Each state decides which polluting sources participate - Each state sets a cap on total CO2 emissions it allows - Each emissions source gets one permit for each ton they emit, up to the amount of the cap - Each state lowers its cap over time - States with too few permits must reduce emissions, buy permits from others, or pay for carbon offsets - Sources with too many permits may sell them - Any source emitting more than permitted will be penalized © 2011 Pearson Education, Inc. Cap-and-trade programs already exist • Chicago Climate Exchange = the world’s first emissions trading program for greenhouse gas reduction - 350 corporations, institutions, etc. - Voluntary but legally binding trading system aims for a 6% reduction in emissions by 2010 • The European Union Emission Trading Scheme - The world’s largest cap-and-trade program - Governments had allocated too many permits • Permits only work if government policies limit emissions © 2011 Pearson Education, Inc. Carbon taxes are another option • Critics say cap-and-trade systems are not effective • Carbon tax = governments charge polluters a fee for each unit of greenhouse gases they emit - Polluters have a financial incentive to reduce emissions - European nations, British Columbia, and Boulder, Colorado have carbon taxes • Polluters pass costs on to consumers • Fee-and-dividend = funds from the carbon tax (fee) are passed to taxpayers as refunds (dividends) © 2011 Pearson Education, Inc. Carbon offsets are popular • Carbon offset = a voluntary payment intended to enable another entity to reduce the greenhouse emissions that one is unable to reduce oneself - The payments offset one’s own emissions • Popular among utilities, businesses, universities, governments, and individuals - Trying to achieve carbon-neutrality, where no net carbon is emitted • Carbon offsets fall short - Needs rigorous oversight to make sure that the offset money accomplishes what it is intended for © 2011 Pearson Education, Inc. You can reduce your carbon footprint • Carbon footprint = expresses the amount of carbon we are responsible for emitting • People may apply many strategies to decrease their footprint • College students must help drive personal and societal changes needed to mitigate climate change • Global climate change may be the biggest challenge facing us and our children - With concerted action, we can avert the most severe impacts © 2011 Pearson Education, Inc. The International Day of Climate Action • On October 24, 2009, 5,200 events were held in 181 nations - “The most widespread day of political action in the planet’s history” © 2011 Pearson Education, Inc. Conclusion • Many factors influence Earth’s climate - Human activities play a major role • Climate change is well underway - Further greenhouse gas emissions will cause severe impacts • More and more scientists are urging immediate action • Reducing emissions and mitigating and adapting to a changing climate is the foremost challenge for our society © 2011 Pearson Education, Inc. QUESTION: Review “Global warming” is defined as: a) b) c) d) Long-term atmospheric conditions Trends and variations in Earth’s climate An increase in Earth’s average temperature Atmospheric gases that absorb infrared radiation © 2011 Pearson Education, Inc. QUESTION: Review Which of the following greenhouse gases is of most concern? a) b) c) d) Carbon dioxide CFCs Methane Water vapor © 2011 Pearson Education, Inc. QUESTION: Review Which of the following is a type of proxy indicator? a) b) c) d) Ice cores Tree rings Sediment cores containing pollen grains All of these are proxy indicators © 2011 Pearson Education, Inc. QUESTION: Review Which of the following are major contributors of global warming? a) b) c) d) Burning fossil fuels and recycling Burning fossil fuels and deforestation Deforestation and nuclear energy Fossil fuels and nuclear energy © 2011 Pearson Education, Inc. QUESTION: Review U.S. emissions of greenhouse gases have: a) b) c) d) Decreased Stabilized Increased Gone away © 2011 Pearson Education, Inc. QUESTION: Review Which statement is true regarding climate change? a) Climate is changing, but the evidence is lacking that humans are the cause of this change. b) There is a broad and clear scientific consensus that climate change is a pressing issue. c) The evidence is not yet strong enough to definitely say that climate is changing. d) Scientists are driven by greed to modify data about climate change. © 2011 Pearson Education, Inc. QUESTION: Review What happens in a cap-and-trade program? a) People pay higher taxes to drive larger cars. b) Industries pay the government higher taxes, which they pass on to consumers in higher prices. c) Industries must buy permits for their emissions. d) Industries can voluntarily decrease emissions. © 2011 Pearson Education, Inc. QUESTION: Viewpoints Do you think cap-and-trade should be enacted in the United States for carbon dioxide emissions? a) Yes, because industries will have incentives to decrease emissions. b) Yes, but only large corporations should be forced to participate. c) No; we are in an economic crisis and don’t need any new taxes. d) No; people will adapt to new conditions. © 2011 Pearson Education, Inc. QUESTION: Interpreting Graphs and Data According to this model, which area will have increased droughts and starvation? a) b) c) d) The United States The tip of South America North Africa Greenland © 2011 Pearson Education, Inc. QUESTION: Interpreting Graphs and Data Which statement is supported by this figure? a) CO2 emissions have stabilized recently. b) CO2 emissions increased only in Hawaii. c) CO2 emissions have increased drastically. d) CO2 emissions average 320 ppm. © 2011 Pearson Education, Inc.