Chapter 16 Climate Change and Ozone Loss

1. Chapter 16 Climate Change and Ozone Loss Carter Kimball, Ryland Burke, and Camille French

2. Case Study: Studying a Volcano to Understand Climate Change • June 1991 eruption • James Hansen makes climate change prediction • Eruption serves as model to test global climate. • Scientists and politicians are convinced.

3. 16-1 Past Climate Change and the Natural Greenhouse Effect • Past historic changes • The natural Greenhouse Effect • Major Greenhouse Gases

4. Historic Changes in Earth’s Temperature • Earth has experienced prolonged periods of global warming and global cooling • These are called glacial and interglacial periods • The agricultural period stabilized the climate

5. The Natural Greenhouse Effect • This is when gases get trapped in the atmosphere and absorb heat. • The absorbed heat raises the global temperature • The two Major greenhouse gases are Water vapor and Carbon dioxide Svante Arrhenius discovered this tropospheric heating effect in 1896

7. 16-2 Climate Change and Human Activities • Signs of a Warming troposphere • Scientific consensus on future climate change • Why should we be concerned about a warmer earth?

8. Signs that the Troposphere is Warming • Since 1861 the concentrations of CO2, CH4, and N2O have risen sharply and the temp has risen .8 degrees Celsius • The 20th century is the hottest in the past 1000 years • Glacial Ice is melting causing sea levels to rise • Permafrost is melting around the world • The 16 warmest years recorded have been in the past 30 years

9. Scientific Consensus on Future Climate Change • There is newer and better evidence that most of the climate change in the last 50 years is caused by human activities • It is very likely that the earths mean surface temp will increase 1.4-5.8 degrees between 2000 and 2100

10. Why Should we be Concerned about a Warmer Earth? • The concern is not with the temp. change, but the speed of the change • Rapid change can effect the availability of resources, and traditions and activities kept for generations • The Natl. Academy of Sciences in 2002 suggested that Temp. can increase drastically in only a decade or two (in past up to 10 C) • This could cause ecosystems to collapse, major flooding, wildlife disappearances, disease, Storms

11. Must be viewed as a serious threat to global stability and should be elevated beyond a scientific debate to a US national security concern. • Most serious problem we are facing today. More serious than terrorism.

12. 16. 3 Factors Affecting the Earth’s Temperature • Oceans remove CO2 and heat from the atmosphere. • Currents help create Earth’s present climate. • Climate change will disrupt currents. • Warmer temperatures create cloud cover than can either warm or cool the earth’s surface. • Jet contrail emissions can contribute to tropospheric warming.

13. 16. 3 Factors Affecting the Earth’s Temperature (cont’d) • Aerosols and other air pollutants are released into the troposphere by volcanic eruptions and human activities. • These particles can contribute to warming and cooling patterns. • Soot/black carbon aerosols • Increased CO2 levels could increase photosynthesis. • Methane hydrates in permafrost

14. 16.4 Possible Effects of a Warmer World • Some areas will benefit from increased global temperatures. • Other areas will suffer. • Risk of wild fires will increase. • Higher temperatures will cause tree deaths, loss of biodiversity, species population depletion. • Will encourage population growth of “bad” species. • Most vulnerable ecosystems… • Effects of sea level rise… • Largest burden of global warming will fall on the poorer countries.

15. 16.5 Dealing with the Threat of Global Warming

16. Why Climate Change is Difficult to Deal With • Many complex causes • Global problem • Long-term issue • Harmful and beneficial impacts of climate change are not spread evenly • Can’t stop climate change but we can slow its rate and adapt to its effects • Reducing global warming can disrupt economies and lifestyles

17. Solutions: What Are Our Options? • Disagreements persist about what should be done • Wait-and-See Strategy • Act Now to Reduce Risk Strategy • Act Now / No Regrets Strategy

18. Solutions to Global Warming Prevention Cleanup • Improve energy efficiency • Reduce fossil fuel use • Switch to carbon-free renewable energy • Reduce deforestation • Remove CO2 from smokestacks and vehicles • Planting trees to store CO2 • Store CO2 deep underground or in the deep ocean Fig. 16-13, p. 379

19. Removing and Storing CO2 Fig. 16-14, p. 380

20. Government Role in Reducing Climate Change • Carbon or Energy Taxes • Increase renewable energy subsidies • Reduce subsidies on fossil fuel • Technology Transfer

21. Kyoto Protocol • Required 39 developed countries to cut emissions to 5.2% below 1990 levels by 2012 • Didn’t require developing countries to cut emissions • Bush withdrew U.S. from Protocol in 2001

22. Kyoto Protocol Percent Change in Emissions in 2007 compared to 1990

23. What You Can Do to Reduce Your CO2 Emissions • Drive a fuel efficient car, walk, bike, or carpool • Energy efficient appliances • Reduce garbage / recycle • Compact fluorescent bulbs • Low-flow shower head

24. 16-6 Ozone Depletion in the Stratosphere

25. Ozone Depletion • Ozone (03) in stratosphere blocks 95% of sun’s harmful UV radiation • Ozone thinning is greatest at poles and present everywhere except tropics • Caused by chlorofluorocarbons (CFCs)

26. CFC’s and Ozone Depletion

27. Effects of Ozone Depletion • More skin cancer and eye cataracts in humans • Damage to crops and forests • Decreased populations of UV sensitive species • Increased acid deposition and photochemical smog • Accelerates global warming by decreasing ocean uptake of CO2

28. 16-7 Protecting the Ozone Layer

29. Reducing Ozone Depletion • Stop using Ozone Depleting Chemicals (ODCs) • Montreal Protocol: 36 countries met to reduce CFC emissions by 35% by 2000 (didn’t include ODCs) • Copenhagen Protocol: 93 countries amended Montreal Protocol to phase out ODCs