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Global environmental changes
- 1. Dr/ Eman Mortada Associateprofessor In public health and preventive medicine Environmental Changes and Challenges for Health
- 2. Climate change Global warming Ozonedepletion Fresh water supplies Desertification and deforstation Loss of biodiversity CONTENTS
- 3. Definition of EnvironmentalChange • Environmental change is defined as a change or disturbance of the environment caused by human influences or natural ecological processes.
- 4. FACTS WE MustKNOW
- 5. Global temperaturehas increased 0.5-1.0°F since the late 19th century. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased.
- 6. 5 main globalenvironmental changes The five main global environmental changes which are currently on the agenda: • Climate change • Ozone depletion • Loss of biodiversity • Fresh water supplies • Persistent organic pollutants
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- 8. 1- Climate change •What is climate change? • What are the environmental consequences? • What does it mean for human health?
- 9. Definition of climatechange: Refers to a long-term change (usually an increase) in global temperatures The greatest challenge facing the world at the beginning of the last century.” the average global temperature has risen by 0.75 degrees “the most important long-term issue which we face as a global community”.
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- 11. Global warming • Itrefers to an average increase in the earth temperature
- 12. The Earth WithNo Atmosphere (infrared)
- 13. Earth With AnAtmosphere That Includes Greenhouse Gases Partly Greenhouse Gases Make the Earth Warmer by Slowing the Loss of Infrared Radiation (infrared)
- 14. Principal Atmospheric Gases Nitrogen(N2) Oxygen (O2) Non-Greenhouse Gases 99% Carbon Dioxide (CO2) Greenhouse Gases 1% Methane (CH4) Water vapor
- 16. The real greenhouse Greenhouseswork by trapping heat from the sun Glass let in light short waves But Keep in heat ( infrared long)waves from escaping
- 17. What is theGreenhouse effect? • The greenhouse effect is the rise in the Earth average temperature because certain gases in the atmosphere trap heat from the Sun’s rays.
- 18. Importance of greenhouseeffect 1- Existence of life: heating effect of greenhouse gases makes existence of life is possible in earth. 2- Maintains ecosystem: Protects the plants and gives them new lives and along with maintaining earth’s average temperature it also protects the existing bio-diversity. 3- Melting of ice and snow 4- Evaporation of water
- 19. The problem Rapidly risinggreenhouse gases
- 20. Causes of globalwarming Manmade causes 1- Air pollution due to a. burning fossil fuel b. industrialization c. coal mining 2- Deforestation Natural causes 1- volcanic eruption 2- release of methane gas from arctic tundra and wetland Global warming is caused by a build-up of greenhouses gases, which leads to an increase in the Earth’s temperature. Enhanced greenhouse effect may lead to significant climate change.
- 21. Greenhouse gases andeffect Key greenhouses gases include: carbon dioxide (CO2) methane (CH4) water vapour (H2O) nitrous oxide (N2O) Carbon dioxide is one of the most important greenhouse gases because atmospheric concentrations have risen dramatically over the past century.
- 22. GLOBAL WARMING vsTHE GREENHOUSE EFFECT
- 23. Consequenses for theenvironment and human health Some expected impacts will be beneficial - but most will be adverse
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- 25. Direct effects onhuman health Extreme weather conditions: • Temperature-related effects heat stress. • Storms accidents and loss of housing. • Droughts limited access to water and food • Floods accidents and loss of housing. Heat wave
- 26. Temperature Heat-wave related mortalityand morbidity • Heat waves can cause death directly through causing illnesses. • Aggravation of pre-existing heat-sensitive medical conditions. • Stress from extreme heat can cause myocardial infarction, sudden cardiac death
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- 29. Floods in Egypt2006 Floods in Italy 2008 Floods in Saudi Arabia 2013 Floods in Denmark 2010
- 30. Flood-related diseases • Floodsdisrupt basic sanitation systems diarrheal disease outbreaks via fecal-oral route. • Contamination of drinking water and facilities with pathogens from human or animal sewage water-borne diseases such as dysentery, hepatitis A, cholera, typhoid fever.
- 31. Indirect effects onhuman health Vector-borne diseases (change in vector distribution). Water-borne diseases (quantity, quality). Food-related diseases (availability, quality). Health effects related to changes in air quality. (e.g pollen allergies). Melting of ice-sheets in the Arctic.
- 32. Vector-borne diseases Malaria Transmittedby mosquitoes Occurs in 97 counties 207 million people infected in 2012 (90% in sub-saharan Africa) 627 000 deaths (482 000 among children under five)
- 33. Vector-borne diseases Lymphatic filariasis (elephantiasis) Transmitted by mosquitoes Mosquito breed in ponds 120 million people infected in 2012 40 million people disfigured and incapacitated
- 34. Elephantiasis Unilateral elephantiasis Severecase of elephantiasis
- 35. Vector-borne diseases Schistosomiasis Transmittedby snails Snails breed in fresh water Occurs in 78 counties 249 million people required treatment in 2012 (90 % in sub-Saharan Africa) http://news.ku.dk
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- 37. Melting ice andrising sea level Global warming causes the polar ice sheets melt. It increases the sea-level. It will possibly rise 18 cm by 2030 and 58 cm by 2090. Flooding will probably occur in lowlands. Many cities along the coast may be under sea water. The loss of polar ice will have a profound effect on animal habitats.
- 38. Food supply Rising temperatures Decreasethe production of staple foods in many of the poorest regions Increasing risks of malnutrition
- 39. Population displacement Rising sealevels Increase the risk of coastal flooding Necessitate population displacement • More than half of the world's population now lives within 60km of the sea. Destruction of island communities Relocations of populations
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- 42. 2- Ozone depletion Stratospheric ozone layer is protective absorbs UV radiation and thus prevents it from reaching the surface of the earth where it would damage the DNA of plants and animals (acts as a protective radiation shield).
- 43. What damages theozone layer? CFCs are used in: fridges and freezers, air conditioners, aerosol spray cans, and packaging materials such as polystyrene. Chlorofluorocarbons (CFCs), which contain the elements carbon, hydrogen, chlorine and fluorine.
- 44. Ozone Depletion process (CFCs), enter the upper atmosphere and break down ozone molecules. When ozone breaks down, the ozone layer thins, Depletion of ozone layer leads to increase in harmful UV rays reach Earth.
- 45. Ozone Hole These imagesof the ozone hole were taken by NASA between September 1981 and September 1999. First identified in 1985 over Antarctica Areas of major ozone thinning, called ozone holes, appear regularly over Antarctica
- 46. Ozone Depletion EffectsOn: ANIMALS (Marine Life) HUMAN PLANTS
- 47. Effects of OzoneDepletion • Higher levels of UV-radiation hitting the earth – Skin cancer – Eye cataracts – Weakened immunity • May disrupt ecosystems • May damage crops and forests
- 48. Recovery of OzoneLayer • The Vienna Convention for the protection of the Ozone layer 1985 • Montreal Protocol (1987) – Reduction of CFCs – Phase out of all ozone destroying chemicals is underway globally • The production and use of CFCs is now banned in many countries and could be worldwide in a few years. • spray cans no longer contain CFC propellants. • Satellite pictures in 2000 indicated that ozone layer was recovering • Full recovery will not occur until 2050
- 50. 3- Loss ofbiodiversity
- 51. What does biodiversitymean? Biodiversity refers to the variability of species . Necessary for healthy ecosystem functioning
- 52. Loss of biodiversity Asa result of human activities, especially the destruction of tropical rain forests and other habitats. Plants and animals are becoming extinct at a faster rate than the planet has ever previously experienced.
- 53. Causes of Lossof biodiversity Pollution (e.g. Eradication or malformatio n) Habitat loss (e.g. Snail vector of schistosomias is) Biotic change (e.g. Change in life cycles/transmi ssion cycles)
- 54. 4- Fresh watersupplies
- 55. 4- Fresh watersupplies Scarce and unclean water supplies are critical public health problems in much of the world. Worldwide water scarcity
- 56. of the world’spopulation 40 %
- 57. Reduced availabilityof drinking water. Reduced possibilities of washing, hygiene and sanitation. Impact on intestinal infectious diseases (e.g., Cholera). Scarcity in food supplies. Tensions and armed conflicts in the struggle for water supplies (e.g. Ethiopia and Sudan due to the need of irrigation). Consequences
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- 59. Water-borne diseases Diarrhea Typhoid Hepatitis Dysentery Giardiasis Cholera Caused byfecal contamination of drinking water ”Water-borne diseases are likely to emerge in areas experiencing warmer weather and water scarcity such as tropical zones and the Arabian Peninsula”. Report N° 64635 – MNA. October 2011. World Bank –Sustainable Development Department- Middle East and North Africal Region: Adaptation to a Changing Climate in the Arab Countries, MNA Flagship Report, Chapter 7
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- 61. A- Malnutrition &Famine • Climate change affects the agricultural sector and food production • Less water available for irrigation will reduce crop yields.
- 62. Currently, 800 millionpeople suffer from malnutrituion globally
- 63. • 32 millionin 16 of the 22 Arab counties (eg. Sudan, Yemen).
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- 65. • Sea food??????? •Sea food contaminated with metals.
- 66. • Crops ??????? •Crops contaminate with pesticides or microbes.
- 67. • Drought canencourage prolifration of crop pests and the spread of mold.
- 68. • Change inocean parameters can lead to algal blooms producing toxins, which may be ingested through shellfish by humans.
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- 70. 5- Persistent organicpollutants (POP’s) • Lead and other heavy metals have become widely distributed in the world environment. • The worst pollutants are synthetic chemicals, particularly the persistant organic (POP’s) including polychlorinated biphenyls (PCB’s). • Highly toxic in the environment, do not break down, and accumulate in the food chain.
- 71. Persistence Toxins caneither degrade quickly or remain unaltered and persist for decades Rates of degradation depends on temperature, moisture, and sun exposure Breakdown products = toxicants degrade into simpler products. May be more or less harmful than the original substance DDT degrades into DDE, which is also highly persistent
- 72. Bioaccumulation It is theProcess leading to higher concentrations in organisms than the surrounding environment • Fat-soluble ones lipophilic substances are stored. • DDT is persistent and fat soluble, so builds up in tissues: bioaccumulation.
- 73. • Poisons moveup the food chain • The increased concentration of toxic chemicals in the tissues of organisms that are at higher levels in food webs • Diagram is example of biomagnification of DDT • toxicants concentrate in top predators • At each trophic level, chemical concentration increases. • DDT concentrations increase from plankton to fish to fish-eating birds. Biomagnifications
- 74. POP’s affectthe human immune system. Increases susceptibilty to respiratory infetions. Exposure to low concentrations from the environment can pose chronic health risks (e.g. cancer). Consequences
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- 76. 6- Desertification Overgrazingand developing of grasslands that border deserts transform the grasslands into deserts. As a result: agricultural output decreases, habitats available to native species are lost.
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- 78. 7- Deforestation Clear-cuttingof forests causes erosion, flooding, and changes in weather patterns. The burn method of clearing tropical rain forests for agriculture increases atmospheric CO2, which contributes to the greenhouse effect. Because most of the nutrients in a tropical rain forest are stored in the vegetation, burning the forest destroys the nutrients.