1. The Water Planet Lecture 21 Global environmental change Yair Rosenthal

2. Geosphere Land use changes Biomass burning Deforestation Overgrazing and desertification Mining, construction, urban growth

3. Hydrosphere River damming Acidification of lakes Groundwater contamination Coastal and estuarine pollution Sea level rise Changes in precipitation

4. Atmosphere The increase in greenhouse gases from fossil fuel burning (global warming) Ozone depletion (CFC’s) Acid rain

5. Biosphere Perturbation of the natural biogeochemical cycles Ecological changes - destruction of habitats Decrease in biodiversity Genetic contamination of natural species with domesticated/agriculture species Over hunting, fishing etc.

6. Environmental change

7. Aswan Dam, Egypt

8. Nile River discharge before and after the construction of the Aswan Dam

9. Some facts About 95 percent of Egypt's population lives within 12 miles of the Nile River. Since the dam was completed in 1970: Freshwater discharge decreased by x4 Nutrients input to the Mediterranea Sea declined The fertility of Egypt's farmland has gradually decreased. Today, more than half of Egypt's soil is rated medium to poor. BUT Effects of severe draughts have deminished

10. Kesterson Reservoir, California Dissolved selenium carried by runoff from the mountains to the alluvial fans where it has been deposited for “ages”. Recently, however, irrigation leaches Se from the soil and flushes it into the reservoir where it reached toxic levels

11. Mining

12. Local sewage impacts

13. Industrial contamination of groundwater aquifers

14. Acid rain

15. Acid rain- causes and results

17. Deforestation and biomass burning

18. From rainforest to agriculture- clear cutting

19. Rondonia, Brazil 1975

20. Rondonia 1986 The “herring bone” pattern

21. Rondonia 1992

22. Rondonia 1996

26. Deforestation in Costa Rica

27. Desertification susceptibility

29. Overgrazing in the Sahel

30. Desertification in North Africa

31. Rainfall in the Sahel before and after the industrial revolution Draughts promote dust storms