1. Climate Disruption and Ozone Depletion Chapter 15, Part 2

2. H OW MIGHT THE EARTH ’ S CLIMATE CHANGE IN THE FUTURE ? Section 15-4 Weather temperature and precipitation in a given area over a period of hours or days. Climate temperature and precipitation over at least 30 years.

3. The NATURAL Greenhouse Effect ➢ Major factors shaping the earth’s climate: ● The sun. ● Atmosphere -Greenhouse effect that warms the earth’s lower troposphere and surface because of the presence of greenhouse gases. -Natural cooling process through water vapor in the troposphere (heat rises). ● Oceans store CO 2 and heat, evaporate and receive water, move stored heat to other parts of the world.

4. Past ➢ 3.5 billion years - volcanic emissions, changes in solar input, continents moving have altered climate. ➢ 900,000 years - glacial (cooling) and interglacial (warming) periods. ➢ 10,000 years – steady interglacial period ➢ 1000 years – temp. rise, esp. w/ burning more fossil fuels. ➢ Past temperature changes are estimated through: - radioisotopes in rocks and fossils - trapped bubbles and other materials in glaciers; - pollen, tree rings - temperature measurements since 1861

5. PAST CLIMATE AND THE GREENHOUSE EFFECT

6. Major Greenhouse GASES ➢ The major greenhouse gases in the lower atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Also CFCs (which cause ozone depletion as well!). ➢ These gases have always been present in the earth’s troposphere in varying concentrations. ● Fluctuations in these gases, plus changes in solar output are the major factors causing the changes in tropospheric temperature over the past 400,000 years.

7. Global warming and human actions ➢ Ice cores show that CO 2 levels in the troposphere are the highest they have been in 650,000 years. ➢ CO 2 from human activities. 285 parts per million (ppm) in1850 to 390 ppm in 2010 (37% inc). ➢ Tipping point @ 450 ppm?

8. How CO2 emissions from the burning of fossil fuels in selected countries increased between 1965 and 2009

9. The SCIENTIFIC Consensus about Future Climate Change ➢ 1906 and 2005, the average global surface temperature has risen by about 0.74 C° (1.3 F°). Primarily since 1980 ➢ (2000–2009) was the warmest decade since, and 2010 was the warmest year on record. ➢ In some parts of the world, glaciers are melting and floating sea ice is shrinking. The Intergovernmental Panel on Climate Change (IPCC) established in 1988 to document past climate changes and project future changes; more than 2,500 climate scientists from more than 130 countries. Findings:

10. FACTORS AFFECTING THE EARTH’S TEMPERATURE ➢ Some factors can amplify (positive feedback) and some can dampen (negative feedback) projected global warming.

11. Unpredictable? ➢ Aerosol and soot pollutants produced by human activities can warm or cool the atmosphere. ➢ Cloud cover can warm or cool the atmosphere as well. Negative (less warming) > Ice caps reflect heat (this is lost with melting) > Increased CO 2 in the troposphere can increase plant photosynthesis (effect slows as plants mature and CO2 released when plants die). Global warming FEEDBACK Can lead to “tipping point” Positive (more warming) ➢ Water absorbs heat, melted ice reflects less sunlight back into space. ➢ Accelerated C cycle in soils = more CO2 in atm ➢ Warmer oceans hold less dissolved CO2Ocean acidification - dissolves CaCO3 in shells, corals ➢ Drought – more fires – more CO2- ↑warming - ↑drought ➢ Warmer temperatures melt permafrost releasing trapped CO 2 and CH 4. ➢ Click for short video on feedback systems Click for short video on feedback systems

12. W HAT ARE SOME POSSIBLE EFFECTS OF A WARMER ATMOSPHERE ? Section 15-5

13. PREDICTIONS ➢ CO2 remains in the atmosphere for 25-100 years, so even if we stop emissions completely now, there will be warming effects for a long time. ➢ A minimum increase in average global temperatures of 2 degrees Celsius is considered inevitable (Hertsgaard, Hot, 2011, p. 51). ➢ This could be accompanied by a 3 ft rise in sea levels by 2100 around California (Pacific Institute, from Hot, p. 35). USGS (2008) predicts 3-6.5 feet. ➢ There is little time to deal with harmful effects. Cut global CO 2 emissions in half over the next 50 years.

14. EFFECTS OF GLOBAL WARMING ➢ A warmer climate would have beneficial and harmful effects but poor nations in the tropics would suffer the most. Impact of oceans rise by 14m on Florida, USA Source: Google Earth http://flood.firetree.net/?ll=27.2839,- 80.7275&z=10&m=14&t=1

15. Satellite data shows a 39% drop in the average cover of summer arctic sea ice between 1979 and 2010 EFFECTS: Melting Ice

16. EFFECTS: Ocean Acidification ➢ A warmer troposphere can decrease the ability of the ocean to remove and store CO 2 by decreasing the nutrient supply for phytoplankton and increasing the acidity of ocean water. ➢ The ocean can absorb massive amounts of CO2. Dissolved CO2 forms carbonic acid in water. ➢ More CO2 = More ocean acidity ➢ This lowers the pH = “Acidification” ➢ Can pose problems for marine organisms ➢ http://www.nsf.gov/news/special_reports/degree/carbon.jsp http://www.nsf.gov/news/special_reports/degree/carbon.jsp

17. EFFECTS: Rising Sea Levels ➢ During this century rising seas levels are projected to flood low-lying urban areas, coastal estuaries, wetlands, coral reefs, and barrier islands and beaches. ➢ If seas levels rise by 9-88cm during this century, most of the Maldives islands and their coral reefs will be flooded. ➢ 150 million coastal people could be displaced

18. EFFECTS: Changing Ocean Currents ➢ Global warming could alter ocean currents and cause both excessive warming and severe cooling. Dense, salty, cool water in north Atlantic initiates the currents above. Climate change could bring more fresh water (less dense) to N Altantic and alter or stop the current.

19. EFFECTS: Extreme Weather ➢ Global warming will lead to prolonged heat waves and droughts in some areas and prolonged heavy rains and increased flooding in other areas.

20. EFFECTS: Biodiversity Winners and Losers ➢ Possible effects of global warming on the geographic range of beech trees based on ecological evidence and computer models. 30% of the land-based plant and animal species assessed so far could disappear if the average global temperature change exceeds 1.5–2.5º. Especially: -Plant and animal species in colder climates -Species at higher elevations -Plant and animal species with limited ranges -Those with limited tolerance for temperature change. -Coral reefs. -Coastal wetlands.

21. EFFECTS: Agriculture ➢ By 2059 up to 45% of the world’s land area could experience extreme drought. ➢ By 2050, 200–600 million more people could face starvation and malnutrition ➢ In a warmer world, agricultural productivity may increase in some areas and decrease in others. ➢ Crop and fish production in some areas could be reduced by rising sea levels that would flood river deltas. ➢ Global warming will increase deaths from: ● Heat and disruption of food supply. ● Spread of tropical diseases to temperate regions. ● Increase the number of environmental refugees.

22. Effects for non-human organisms as well: The orange-colored trees are those that are dead or dying—killed by mountain pine beetles EFFECTS: Health Microbes that cause infectious tropical diseases such as dengue fever and yellow fever are likely to expand their ranges Areas in blue show counties in 28 U.S. states where one or both species of mosquitoes that transmit dengue fever have been found as of 2005

23. W HAT CAN WE DO TO SLOW PROJECTED CLIMATE CHANGE ? Section 15-6

24. Scientists have come up with this list of possible climate change tipping points

25. DEALING WITH GLOBAL WARMING ➢ Climate change is such a difficult problem to deal with because: ● The problem is global. ● The effects will last a long time. ● The problem is a long-term political issue. ● The harmful and beneficial impacts of climate change are not spread evenly. ● Many actions that might reduce the threat are controversial because they can impact economies and lifestyles.

26. DEALING WITH GLOBAL WARMING ➢ Two general ways to deal with global warming: ● Mitigation that reduces greenhouse gas emissions: reduce fossil fuel use ● Adaptation, where we recognize that some warming is unavoidable and devise strategies to reduce its harmful effects: build sea walls

27. Cut fossil fuel use (especially coal) Shift from coal to natural gas Improve energy efficiency Shift to renewable energy resources Transfer energy efficiency and renewable energy technologies to developing countries Reduce deforestation Use more sustainable agriculture and forestry Limit urban sprawl Reduce poverty Slow population growth Remove CO 2 from smoke stack and vehicle emissions Store (sequester) CO2 by planting trees Sequester CO 2 deep underground Sequester CO 2 in soil by using no-till cultivation and taking cropland out of production Sequester CO 2 in the deep ocean Repair leaky natural gas pipelines and facilities Use animal feeds that reduce CH 4 emissions by belching cows Solutions Global Warming PreventionCleanup Mitigation

28. Adaptatio n Move hazardous material storage tanks away from coast Connect wildlife reserves with corridors Develop crops that need less water Waste less water Move people away from low-lying coastal areas Stockpile 1- to 5-year supply of key foods Expand existing wildlife reserves toward poles Prohibit new construction on low-lying coastal areas or build houses on stilts …and dam glacial lakes, colony on Mars?, etc. Sea wall

29. SOLUTIONS: Reducing the Threat ➢ We can improve energy efficiency, rely more on carbon-free renewable energy resources, and find ways to keep much of the CO 2 we produce out of the troposphere.

30. SOLUTIONS: Removing and Storing CO 2 ➢ Methods for removing CO 2 from the atmosphere or from smokestacks and storing (sequestering) it.

31. DEALING WITH GLOBAL WARMING: Legal and cultural changes ➢ Tax greenhouse gas emissions, increase subsidies and tax breaks for saving energy, use cap-and-trade ➢ Regulate CO2 and CH4, phase out polluting energies (ie coal) ➢ A crash program to MITIGATE and ADAPT to global warming now is very likely to cost less than waiting and having to deal with its harmful effects later. ➢ BUT… getting countries to agree on reducing their greenhouse emissions is difficult. ➢ A 2006 poll showed that 83% of Americans want more leadership from federal government on dealing with global warming.

32. International Climate Negotiations: The Kyoto Protocol ● Treaty on global warming (signed 1997) which first phase went into effect January, 2005 with 189 countries participating. ● It requires 38 participating developed countries to cut their emissions of CO 2, CH 4, and N 2 O to 5.2% below their 1990 levels by 2012. ● Developing countries were excluded. The U.S. did not sign, but California and Maine are participating. U.S. did not sign because developing countries such as China, India and Brazil were excluded. Negotiations have failed to extend the original agreement after 2012.

33. Global Leadership ➢ Costa Rica aims to be the first country to become carbon neutral by cutting its net carbon emissions to zero by 2030. ➢ China has one of the world’s most intensive energy efficiency programs (still a big polluter though). ➢ By 2010, at least 30 U.S. states had set goals for reducing greenhouse gas emissions. ➢ Since 1990, local governments in more than 650 cities around the world (including more than 450 U.S. cities) have established programs to reduce their greenhouse gas emissions. ➢ California has adopted a goal of reducing its greenhouse gas emission to 1990 levels by 2020, and 80% below by 2050. ➢ Companies as well…see textbook

34. Individual Leadership

35. H OW HAVE WE DEPLETED OZONE IN THE STRATOSPHERE AND WHAT CAN WE DO ABOUT IT ? Section 15-7

36. OZONE DEPLETION IN THE STRATOSPHERE ➢ Less ozone in the stratosphere allows for more harmful UV radiation to reach the earth’s surface. ● The ozone layer keeps about 95% of the sun’s harmful UV radiation from reaching the earth’s surface. ● Chlorofluorocarbon (CFCs) have lowered the average concentrations of ozone in the stratosphere. ● In 1988 CFCs were no longer manufactured. ➢ Ozone thinning: caused by CFCs and other ozone depleting chemicals (ODCs). ● Increased UV radiation reaching the earth’s surface from ozone depletion in the stratosphere is harmful to human health, crops, forests, animals, and materials such as plastic and paints.

37. A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O 2. Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. Sun Repeated many times The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). Summary of Reactions CCl 3 F + UV Cl + CCl 2 F Cl + O 3 ClO + O 2 Cl + O Cl + O2 UV radiation The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2). Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. Cl

38. OZONE DEPLETION IN THE STRATOSPHERE ➢ Since 1976, in Antarctica, ozone levels have markedly decreased during October and November. ➢ Worst at cold poles b/c CFC associates with ice crystals and builds up there. ➢ In 2008, the area of ozone thinning was still near its record high of 29 million square kilometers (11 million square miles), set in 2006. ➢ Models indicate that even with immediate and sustained action. ● About 60 years for the earth’s ozone layer to recover the levels of ozone it had in 1980. ● About 100 years for recovery to pre-1950 levels.

39. Human Health Worse sunburn More eye cataracts More skin cancers Immune system suppression Food and Forests Reduced yields for some crops Reduced seafood supplies from reduced phytoplankton Decreased forest productivity for UV-sensitive tree species Wildlife Increased eye cataracts in some species Decreased population of aquatic species sensitive to UV radiation Reduced population of surface phytoplankton Disrupted aquatic food webs from reduced phytoplankton Air Pollution and Materials Increased acid deposition Increased photochemical smog Degradation of outdoor paints and plastics Global Warming Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases Effects of Ozone Depletion Natural Capital Degradation

40. Case Study: Skin Cancer ➢ Structure of the human skin and relationship between radiation and skin cancer.

41. PROTECTING THE OZONE LAYER ➢ To reduce ozone depletion, we must stop producing all ozone-depleting chemicals. ➢ A big step towards doing this was the Montreal Protocol (1987). The most widely ratified treaty in UN history. In 1992, the Copenhagen Protocol was an amendment signed by 195 countries. ➢ If followed, ozone predicted to recover by 2050.

42. What Can You Do? Stay out of the sun, especially between 10 A.M. and 3 P.M. Do not use tanning parlors or sunlamps. When in the sun, wear protective clothing and sun– glasses that protect against UV-A and UV-B radiation. Be aware that overcast skies do not protect you. Do not expose yourself to the sun if you are taking antibiotics or birth control pills. Use a sunscreen with a protection factor of 15 or 30 anytime you are in the sun if you have light skin. Examine your skin and scalp at least once a month for moles or warts that change in size, shape, or color or sores that keep oozing, bleeding, and crusting over. If you observe any of these signs, consult a doctor immediately. Reducing Exposure to UV Radiation

43. Three big ideas Prevent outdoor and indoor air pollution (from Part 1). Reducing the projected harmful effects of rapid climate disruption during this century requires emergency action. Continue phasing out the use of chemicals that have reduced stratospheric ozone levels.