Presentation on theme: "Impact of Human Population on the Environment"— Presentation transcript:
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 LayerOzone, O3, is a naturally occurring gas that collects in the stratosphere and shields the Earth from harmful ultraviolet radiation released from the Sun.
3 One CFC can destroy 100,000 ozone molecules Hole in the Ozone LayerCertain 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 LayerCFCs 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 LayerSince the 1980’s, atmospheric measurements have shown a periodic hole in the ozone layer over Antarctica. As a result, the amount of skin cancer and cataracts have increased worldwide.
6 Hole in the Ozone LayerInternational effort 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 LevelsSince the industrial revolution that began in the 1850’s, the levels of carbon dioxide in the atmosphere has increased by over 30%
8 Increased CO2 LevelsReasons for the increase in CO2 levels are mainly due to increase in burning of fossil fuels for energy or combustion
9 Increased CO2 LevelsCO2 is released from coal power plants; combustion engines; and from burning wood especially forests.Slash and burn practice of clearing tropical rainforests to make room for more farmland
11 Increased CO2 LevelsNot 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 CO2 from the atmosphere during photosynthesis
12 Increased CO2 LevelsCarbon dioxide is one of the greenhouse gases. Other greenhouse gases include: water vapor, methane, CFCs, Ozone, and nitrous oxide.Methane is the second largest contributor to increase in greenhouse gases
13 Greenhouse EffectMethane is released by cows, every time they breathe. However, methane is also released from mining practices, landfills, and during the production of gas products.
14 Greenhouse EffectA Greenhouse, made of glass, allows light radiation in that heats the ground. Heated objects emit infrared radiation, heat, that cannot pass through glass and becomes trapped.
15 Greenhouse EffectIn the atmosphere, greenhouse gasses allow light radiation to pass through but trap infrared radiation, thus keeping the Earth warm.95% of the atmosphere on Venus is 95% CO2 – Temperatures on Venus reach 900F
16 Global Climate ChangeMeasurements from ice cores in Antarctica, the temperature has varied periodically through time. Changes in CO2 levels coincide with the changes in temperature.
17 Global Climate Change Cooling Decrease in atmospheric CO2 Decrease in TemperatureDecrease in Temperature Glacial FormationGlacial Formation Higher reflection of sunlightHigher reflection of sunlight Lower light intensityLower light intensity Shorter Growing SeasonsShorter growing season Less photosynthesisLess photosynthesis Increase in atmospheric CO2
18 Global Climate Change Warming Increase in atmospheric CO2 Increase in temperatureIncrease in temperature Melting of glaciersMelting of glaciers Decrease of light reflectionDecrease of light reflection Increase in light intensityIncrease in light intensity Increase in PhotosynthesisIncrease in photosynthesis Decrease in atmospheric CO2Decrease in atmospheric CO2 Decrease in Temperature
19 Global Climate ChangeSince the 1900’s, global levels of atmospheric CO2 have increased dramatically.The increase with CO2 levels do coincide with the advent of the industrial revolution.
20 Global Climate ChangeSince 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 ChangeScientists use carbon isotopes to determine if atmospheric CO2 was derived from the burning of fossil fuels or natural earth’s processesClimate Model – Both natural CO2 and that from the burning of fossil fuels
22 Climate Model – Just atmospheric CO2 from natural earth’s processes Global Climate ChangeEvidence 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 ChangeIf the warming trend continues, it could lead to a change in our global climate where there is a significant change in the “average” temperature
24 Global Climate ChangePossible changes if the global climate changes could include:Melting of Polar Ice CapsRise in Sea LevelDisappearance of Many IslandsFlooding of Major Coastal Cities
25 Global Climate ChangePossible changes if the global climate changes could include:More Extreme Weather Patterns(Hot and Cold)Change in Agricultural regionsDestruction of Coral Reefs
26 Acid RainAcid rain is created when sulfur oxides and nitrogen oxides from the burning of fossil fuels combine with rain to make it more acidic
27 Acid RainAcid rain washes minerals such as calcium and magnesium from the soil that plants need to grow
28 SmogSmog refers to a mixture of smoke and fog in the air. Smog traditionally arose from smoke released from coal burning plants. However, since the 1950’s, the largest contribution to smog has been from automobile exhaust.
29 SmogSmog is created when nitrogen oxides (NOx) and volatile organic compounds (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 SmogSmog or ozone is particularly harmful to older and very young people, as well as people with existing respiratory issues.
31 SmogThe EPA now monitors ozone levels on a daily basis and issues ozone warning when levels reach dangerous levels, especially in the summer time.