Global Environmental Problems

1. Global Environmental Problems David P. Chynoweth University of Florida

2. Outline Of Problems (1) • Atmosphere • green house gases (climate change) • acid rain • ozone (uv light penetration)

3. Outline Of Problems (2) • Ecosphere • habitat loss • freshwater supply • bioinvasion • alteration of fire cycles • persistent organic pollutants • nitrogen pollution • overfishing

4. Outline Of Problems (3) • Social Sphere • population growth • infectious disease • economic exploitation • natural resource exploitation • human resource exploitation

5. Global Warming

6. What is Global Warming?

7. SOURCES OR CAUSES OF INCREASES IN GASES (1) • Carbon Dioxide • Fossil fuel combustion • Deforestation • Methane • Flooded soil crops (e.g. rice) • Fossil fuel mining • Ruminants • Landfills • Organic wastes • Human stimulated eutrophication

8. SOURCES OR CAUSES OF INCREASES IN GASES (2) • Nitrogen Oxides • Nitrogen fertilizers • Fossil fuel combustion • Chlorofluorohydrocarbons • Release of refrigerant CFCs

9. CONCENTRATIONS AND WARMING POTENTIAL OF GREENHOUSE GASES

10. Increase in Greenhouse Gas Concentrations

11. Potential Effects of Global Warming • Elevated temperatures of the biosphere • melting of polar ice • increase in sea level (flooding of major cities) • increase of methane from permafrost • Weather extremes • more rainfall during shorter periods • more evaporation and soil moisture deficiencies • Ecosystem disruption • stress and death of vegetation • migration of animals • Human Health • heat stress • migration of disease vectors

12. CHANGES IN ATMOSPHERIC C02 AND EARTH’S TEMPERATURE CHANGE

13. REMEDIES FOR GLOBAL WARMING • Reduce use of fossil fuels • Reduce energy consumption • Replace fossil fuels with energy forms that don’t release net carbon dioxide (e.g., solar, biomass, wind, hydroelectric, nuclear) • Remove carbon dioxide from combustion gases • Increase standing crop of carbon-fixing plants • reduce deforestation • Reduce anthropogenic sources of methane (flooded crops, releases fossil fuel mining, landfills, organic wastes, ruminants) • Reduce release of N from fertilizers and combustion

14. SOCIOECONOMIC ISSUES • Developed countries use most of the fossil energy. • U.S. has 4% of the world population and uses 25% of the energy • Developing countries use about 10% of energy per capita as the U.S. • In the U.S., energy use is 36% for building, 32% for transportation, and 32% for industry • Power plants waste energy ( a 400 MW plant wastes 800 MW of heat energy) • Developed countries have developed on the basis of use of energy and deforestation. How can we ask emerging countries not to do the same?

15. CO2 EMISSIONS BY COUNTRY

16. Acid Rain

17. Diagram of Acid Rain

18. World Sulfur and Nitrogen Emissions from Fossil Fuels, 1970-94

19. Average Annual Sulfur Dioxide Concentrations, Selected Cities, 1985 and 1995

20. Reduction in SO2 Emission from Utilities in U.S.

21. Relative Contribution of Sources of SOx and NOx

22. Acid Rain Effects in U.S.

23. Acid Rain Effects in Europe

24. Effects of Acid Rain • Acidification of lakes, streams, and soils • direct and indirect effects (release of metals, e.g. Al; wash away of nutrients) • Kill of wildlife (trees, crops, aquatic plants, and animals) • Decay of building materials and paints, statues, and sculptures (e.g. Mya Ruins in Yucatan) • Health problems (respiratory, burning skin and eyes)

25. Correctives (1) • Remove SOx and NOx from stacks (scrub with water and lime) • Use low sulfur fuels • Remove NOx from auto exhaust (catalytic converters) • Use less energy (conservation) • Replace fossil fuels with alternative energy forms (biomass, wind, solar, hydroelectric, nuclear)

26. Correctives (2) • Restore environment (liming, replanting) • Emissions monitoring • SO2, NOx, CO2, vol. flow, and opacity • Use continuous emission monitoring system • Fines for excess pollutant release

27. Ozone

28. The Pros of Ozone • Ozone is a Natural Atmospheric Component that Filter Out Dangerous Uv Irradiation • Ozone cleanses the air and is produced naturally by lightning • Ozone can be used to disinfect air and water

29. The Cons of Ozone • Ozone reacts with other pollutants to product photochemical smog, e.g. LA • The ozone layer is being depleted by halogenated compounds which will allow toxic levels of UV light to pass through the atmosphere • Ozone is a potent oxidizing agent and toxic at levels exceeding 0.1g/m3 (100)ppm.

30. Ozone Sources, Anthropogenic and Natural

31. Ozone Depletion

32. Effect of Ozone on UV Transmision

33. Ozone Levels VS Latitude

34. CFCs as a Function of Altitude

35. Development of Ozone Hole

36. Consequences of Ozone Layer Depletion • caused by chlorofluorohydrocarbons (e.g. freon) • effect is 30 years delayed • lets more uv light in • causes rise in skin cancer, cataracts • weakens immune system • harms photosynthesizers

37. Ozone Level in North Americal

38. Solution • Stop using CFS’s • Atmosphere will recover in 50 years

39. World Production of Chlorofluorocarbons, 1950-97

40. Ozone Reduction

41. Population Trend

42. Population Trend

43. Fresh Water Supply

44. The Problem (1) • Fresh water supplies are being depleted • Use of fresh water from aquifers, groundwater, and lakes is exceeding replenishment by rainfall • Freshwater supplies are being polluted by toxic organic and inorganic compounds

45. The Problem (2) • Dams supply water to some and deprive it from others and have ecological impacts • Overuse of fresh water is causing salt water intrusion of groundwater supplies

46. Global Irrigation Water Use, 1940-95

47. Average Yields on Rain-fed and Irrigated Land, Developing Countries

48. World Irrigated Area, 1900--98

49. World Irrigated Area Per 1,000 People1950-1998 with Projections to 2050

50. Solutions • Conserve water use, especially in industry and agriculture • Move population centers near water supply • Reuse water • Reduce deforestation to maintain hydrological cycle