Presentation on theme: "Impact of Human Population on the Environment Objective 5.03: Assess human population and its impact on local ecosystems and global environments."— Presentation transcript:
Impact of Human Population on the Environment Objective 5.03: Assess human population and its impact on local ecosystems and global environments
Ozone, O3, is a naturally occurring gas that collects in the stratosphere and shields the Earth from harmful ultraviolet radiation released from the Sun. 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
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.
Hole in the Ozone Layer Since the 1980s, 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.
Hole in the Ozone Layer International 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
Increased CO 2 Levels Since the industrial revolution that began in the 1850s, the levels of carbon dioxide in the atmosphere has increased by over 30%
Increased CO 2 Levels Reasons for the increase in CO2 levels are mainly due to increase in burning of fossil fuels for energy or combustion
Increased CO 2 Levels CO2 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
Increased CO 2 Levels
Not only does the burning of a forest release CO 2 into the atmosphere, it also reduces trees that are able to remove and store a lot of CO 2 from the atmosphere during photosynthesis
Carbon dioxide is one of the greenhouse gases. Other greenhouse gases include: water vapor, methane, CFCs, Ozone, and nitrous oxide. Increased CO 2 Levels Methane is the second largest contributor to increase in greenhouse gases
Greenhouse Effect Methane is released by cows, every time they breathe. However, methane is also released from mining practices, landfills, and during the production of gas products.
A 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. Greenhouse Effect
In 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% CO 2 – Temperatures on Venus reach 900F
Global Climate Change Measurements from ice cores in Antarctica, the temperature has varied periodically through time. Changes in CO 2 levels coincide with the changes in temperature.
Global Climate Change Cooling 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 CO 2 Decrease in atmospheric CO 2 Decrease in Temperature
Global Climate Change Warming Increase in atmospheric CO 2 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 CO 2 Decrease in atmospheric CO 2 Decrease in Temperature
Global Climate Change Since the 1900s, global levels of atmospheric CO2 have increased dramatically. The increase with CO2 levels do coincide with the advent of the industrial revolution.
Global Climate Change Since the 1900s, there has also been an increase in global temperature. Although there has been periodically cooler years, the overall trend is still increasing.
Global Climate Change Scientists use carbon isotopes to determine if atmospheric CO2 was derived from the burning of fossil fuels or natural earths processes Climate Model – Both natural CO 2 and that from the burning of fossil fuels
Global Climate Change Evidence shows that atmospheric levels CO2 from natural Earths processes has not increased over the past 100 years. Climate Model – Just atmospheric CO 2 from natural earths processes
Global Climate Change If the warming trend continues, it could lead to a change in our global climate where there is a significant change in the average temperature
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
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
Acid Rain Acid rain is created when sulfur oxides and nitrogen oxides from the burning of fossil fuels combine with rain to make it more acidic
Acid Rain Acid rain washes minerals such as calcium and magnesium from the soil that plants need to grow
Smog refers to a mixture of smoke and fog in the air. Smog traditionally arose from smoke released from coal burning plants. However, since the 1950s, the largest contribution to smog has been from automobile exhaust. Smog
Smog Smog is created when nitrogen oxides (NOx) and volatile organic compounds (VOCs) 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
Smog Smog or ozone is particularly harmful to older and very young people, as well as people with existing respiratory issues.
Smog The EPA now monitors ozone levels on a daily basis and issues ozone warning when levels reach dangerous levels, especially in the summer time.