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global warming ch-07
This document discusses the history of Earth's climate and the causes and effects of global warming. It explains that the Earth formed over 4 billion years ago and its climate has cycled between warming and cooling periods. It also notes that life first appeared around 3.8 billion years ago. The document then discusses how the greenhouse effect works, trapping heat from the sun in the lower atmosphere. It identifies carbon dioxide and methane as greenhouse gases and notes a rise in atmospheric CO2 levels since the industrial revolution due to human activities like burning fossil fuels. The summary concludes that global warming is unequivocal and human-caused, with impacts like rising sea levels and more extreme weather events expected if emissions continue unchecked.
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global warming ch-07
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- 3. Introduction • Is theworld getting warmer? • If so, are the actions of mankind to blame for earth’s temperature increases? • What can/should be done about these issues?
- 4. History of Earth’sClimate • Earth formed ~4.6 billion years ago • Originally very hot • Sun’s energy output only 70% of present • Liquid water present ~4.3 billion years
- 5. History of Earth’sClimate • Life appeared ~3.8 billion years ago • Photosynthesis began 3.5-2.5 billion years ago – Produced oxygen and removed carbon dioxide and methane (greenhouse gases) – Earth went through periods of cooling (“Snowball Earth”) and warming • Earth began cycles of glacial and interglacial periods ~3 million years ago
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- 10. Global warming isthe rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.
- 11. Warming of theclimatesystemis unequivocal, and scientistsare 95-100% certain that it is primarilycausedby increasing concentrations of greenhouse gases producedby human activities suchas the burningof fossilfuelsand deforestation. These findings are recognizedby the nationalscience academies of all major industrialized nations.
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- 13. • he greenhouseeffect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.
- 15. Earth’s Atmospheric Gases Nitrogen(N2) Oxygen (O2) Water (H2O) Carbon Dioxide (CO2) Methane (CH4) Non- Greenhouse Gases 99% Greenhouse Gases 1%
- 17. Worldwide Carbon EmissionsCarbon(109metrictons) 0 1 2 3 4 5 6 7 8 17501800 1850 1900 1950 2000 Year Liquid fuel Total Gas fuel Solid fuel
- 18. Annual Carbon Emissions Annualcarbon emissions Atmospheric CO2 Atmospheric CO2 average 1955 1965 1975 1985 1995 2005 0 4 6 8 2 Year Carbon(109metrictons)
- 19. Future Carbon DioxideLevels • Increasing CO2 emissions, especially in China and developing countries • Likely to double within 150 years: – Increased coal usage – Increased natural gas usage – Decreased petroleum usage (increased cost and decreasing supply)
- 20. Of all U.S.greenhouse gas emissions come from households: • Vehicles • Home Heating • Electricity Households are Big Contributors to Climate Change
- 21. So how caneach of us slow global warming now?
- 22. Because greenhouse gasemissions are tied very closely to our energy consumption, using less fossil fuel based energy puts fewer greenhouse gases into the atmosphere. This will help slow global warming. Reduce our consumption of fossil fuels Mountaintop removal for coal mining near Rawl, West Virginia. 50% of electricity in the United States is produced from coal. (
- 23. Small changes reallyadd up Replace your old refrigerator with a new Energy Star: Annual savings: $90; 700 pounds CO2 Set your thermostat down a few degrees in the winter Annual savings: $135; 1400 pounds CO2 Wash clothes in cold water only Annual savings: $70; 500 pounds CO2 Drive JUST 10 fewer miles per week Annual savings: $80; 520 pounds CO2 Reduce your garbage by 10% through greater recycling or reduced packaging Annual savings: 1200 pounds CO2 Caulk and weather-strip around doors and windows Annual savings: $80; 650 pounds CO2 * These are mid-range estimates from published sources; your savings may vary.
- 24. Blowing Up YourWorld • How many of you walked, bicycled or took public transportation to get to school today, instead of coming by private automobile? Our reliance on cars that burn fossil fuels is one of the major causes of increased levels of carbon dioxide in the atmosphere and it is the primary cause of urban smog. 3 pts u
- 25. Blowing Up YourWorld • How many of you, when you drink a soft drink, throw the container into the garbage? • Throwing away containers of any kind wastes energy and resources and adds to our waste problem. Many towns are running out of landfill space. 3 pts d
- 26. Blowing Up YourWorld How many of you eat fresh vegetables instead of canned or frozen? Fresh vegetables cook more quickly and are usually more nutritious than frozen or canned foods. Canned and frozen vegetables are often over-processed, contain additives, contribute to air pollution (transport and packaging) and add to our waste problem. 4 pts u Blowing Up Your World
- 27. Blowing Up YourWorld • How many of you use a hairdryer or other energy-consuming convenience appliance, especially in the morning? • Hairdryers use a lot of energy. In the morning so much energy demand is put on our grids that power companies have to find other sources of energy just to meet the morning rush hour 2 pts d
- 28. Blowing Up YourWorld How many of you carry your lunch to school in a lunch box or reusable container? Making paper and plastic bags uses energy and resources.
- 29. Blowing Up YourWorld • How many of you eat take-out or cafeteria food that is served in foam or plastic containers? • Polystyrene and other plastic containers are made from precious petrochemicals, do not decompose in landfills, and release toxic gases when they are burned in incinerators. 10 pts d
- 30. Blowing Up YourWorld • How many of you use handkerchiefs instead of tissues and use cloth towels instead of paper towels? • Paper comes from trees. The more of it we use, the more trees that are cut down 2 pts d
- 31. Blowing Up YourWorld • How many are changing incandescent bulbs for new compact fluorescent bulbs? Changing one bulb could save 150 pounds of carbon dioxide per year!
- 32. Our take-home message… Eachof us must take steps to protect our Earth's climate.
- 33. PRESENTED BY :GROUP E GUIDANCE BY PROF. UJAS PANDYA
- 34. GROUP MEMBERS: 1. VIRADIYASIDDHI 2. SAKSHI MEHTA 3. JAY PATEL 4. UZAIR 5. MAYURI PATEL 6. RADHA DESAI