Impact of Human Population on the Environment

1. Impact of Human Population on the Environment Objective 5.03: Assess human population and its impact on local ecosystems and global environments

2. Hole in the Ozone Layer Ozone, O3, is a naturally occurring gas that collects in the stratosphere and shields the Earth from harmful ultravioletradiation released from the Sun.

3. Hole in the Ozone Layer Certain synthetic chemicals, especially chlorofluorocarbons, CFCs, rise into the stratosphere and act as catalysts that break down ozone faster than its formed. One CFC can destroy 100,000 ozone molecules

4. Hole in the Ozone Layer CFCs are commonly used as coolants in air conditioners, cars, and refrigerators. CFCs are also used in aerosol spray cans and to make Styrofoam products.

5. Hole in the Ozone Layer Since the 1980’s, atmospheric measurements have shown a periodichole in the ozone layer overAntarctica. As a result, the amount of skincancer and cataracts have increased worldwide.

6. Hole in the Ozone Layer Internationaleffort began to reduce the use of CFCs by using substitutes and to only allow licensed mechanics to change Freon in car air conditioners. The ozone hole is decreasing yearly and can be expected to be fully repaired by 2050

7. Increased CO2 Levels Since the industrialrevolution that began in the 1850’s, the levels of carbondioxide in the atmosphere has increased by over 30%

8. Increased CO2 Levels Reasons for the increase in CO2 levels are mainly due to increase in burning of fossilfuels for energy or combustion

9. Increased CO2 Levels CO2 is released from coalpowerplants; combustionengines; and from burning wood especially forests. Slash and burn practice of clearing tropical rainforests to make room for more farmland

10. Increased CO2 Levels

11. Increased CO2 Levels Not only does the burning of a forest release CO2 into the atmosphere, it also reduces trees that are able to remove and store a lot of CO2from the atmosphere during photosynthesis

12. Increased CO2 Levels Carbon dioxide is one of the greenhouse gases. Other greenhouse gases include: watervapor, methane, CFCs, Ozone, and nitrous oxide. Methane is the second largest contributor to increase in greenhouse gases

13. Greenhouse Effect Methane is released by cows, every time they breathe. However, methane is also released from mining practices, landfills, and during the productionofgas products.

14. Greenhouse Effect A Greenhouse, made of glass, allows light radiation in that heats the ground. Heated objects emit infraredradiation, heat, that cannot pass through glass and becomes trapped.

15. Greenhouse Effect In the atmosphere,greenhousegasses allow light radiation to pass through but trapinfraredradiation, thus keeping the Earth warm. 95% of the atmosphere on Venus is 95% CO2 – Temperatures on Venus reach 900F

16. Global Climate Change Measurements from ice cores in Antarctica, the temperature has varied periodically through time. Changes in CO2levelscoincide with the changes in temperature.

17. Global Climate Change Cooling Decrease in atmospheric CO2 Decrease in Temperature Decrease in Temperature  Glacial Formation Glacial Formation  Higher reflection of sunlight Higher reflection of sunlight  Lower light intensity Lower light intensity Shorter Growing Seasons Shorter growing season  Less photosynthesis Less photosynthesis Increase in atmospheric CO2

18. Global Climate Change Warming Increase in atmospheric CO2 Increase in temperature Increase in temperature  Melting of glaciers Melting of glaciers  Decrease of light reflection Decrease of light reflection  Increase in light intensity Increase in light intensity  Increase in Photosynthesis Increase in photosynthesis Decrease in atmospheric CO2 Decrease in atmospheric CO2 Decrease in Temperature

19. Global Climate Change • Since the 1900’s, global levels of atmospheric CO2 have increased dramatically. • The increase with CO2 levels do coincide with the advent of the industrialrevolution.

20. Global Climate Change • Since the 1900’s, there has also been an increase in global temperature. • Although there has been periodically cooler years, the overall trend is still increasing.

21. Global Climate Change Scientists use carbonisotopes to determine if atmospheric CO2 was derived from the burning of fossil fuels or natural earth’s processes Climate Model – Both natural CO2 and that from the burning of fossil fuels

22. Global Climate Change Evidence shows that atmospheric levels CO2 from natural Earth’s processes has not increased over the past 100 years. Climate Model – Just atmospheric CO2 from natural earth’s processes

23. Global Climate Change If the warming trend continues, it could lead to a change in our globalclimate where there is a significant change in the “average” temperature

24. Global Climate Change Possible changes if the global climate changes could include: Melting of Polar Ice Caps Rise in Sea Level Disappearance of Many Islands Flooding of Major Coastal Cities

25. Global Climate Change Possible changes if the global climate changes could include: More Extreme Weather Patterns(Hot and Cold) Change in Agricultural regions Destruction of Coral Reefs

26. Acid Rain Acidrain is created when sulfuroxides and nitrogenoxidesfrom the burning of fossilfuels combine with rain to make it more acidic

27. Acid Rain Acid rain washes minerals such as calcium and magnesium from the soil that plants need to grow

28. Smog Smog refers to a mixture of smoke and fog in the air. Smog traditionally arose from smoke released from coalburningplants. However, since the 1950’s, the largest contribution to smog has been from automobileexhaust.

29. Smog Smog is created when nitrogenoxides (NOx) and volatileorganiccompounds (VOC’s) react under sunlight to form ozone. While ozone in the upper stratosphere blocks harmful ultraviolet radiation, it is harmful upon exposure, in the lower troposphere

30. Smog • Smog or ozone is particularly harmful to older and very young people, as well as people with existing respiratory issues.

31. Smog The EPA now monitorsozonelevels on a daily basis and issues ozone warning when levels reach dangerous levels, especially in the summer time.

32. The End