1 / 16

Global warming

Global warming. Key words: combustion, carbon dioxide, methane, deforestation. starter. Rising levels of carbon dioxide. Why?. At the moment the change is seemingly very small at 0.06 0 C per year. Objective How does combustion affect the atmosphere? Success Criteria

mostyn
Télécharger la présentation

Global warming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Global warming Key words: combustion, carbon dioxide, methane, deforestation

  2. starter Rising levels of carbon dioxide. Why? At the moment the change is seemingly very small at 0.060C per year

  3. Objective • How does combustion affect the atmosphere? • Success Criteria • By the end of the lesson I: • know how combustion affects the • atmosphere • know how living organisms affect the • atmosphere • can explain the consequences of global warming

  4. Get the gas right Pollution problem Gas Global warming Carbon dioxide Sulfur dioxide and nitrogen oxides Acid rain Holes in the ozone layer CFCs (Chloroflurocarbons)

  5. The greenhouse effect

  6. The greenhouse effect Draw a diagram and explain the ‘greenhouse effect’

  7. Atmospheric carbon dioxide The worry of rising carbon dioxide levels is that if the earth warms up then the ice caps will melt causing sea levels to rise. There is no evidence of this happening but it would mean that low lying areas will flood and parts of or even whole countries will become submerged!

  8. Carbon dioxide levels Carbon dioxide is one of the most important greenhouse gases because atmospheric concentrations have risen dramatically over the past century. Why do you think this is? Respiration and combustion produce carbon dioxide Photosynthesis removes carbon dioxide More rice fields and cattle have led to increased levels of methane in the atmosphere. Increased levels of greenhouse gases (carbon dioxide and methane) may cause global warming as a result of the Greenhouse effect • Burning fossil fuels (combustion), • deforestation and • flooding land for the construction of hydroelectric dams • have all contributed to rising levels of • carbon dioxide. • Another greenhouse effect harming the • environment is methane which is produced • by cows in large amounts and by rice fields!

  9. Global warming and greenhouse gases One of the greatest threats caused by air pollution is global warming. Global warming is caused by a build-up of greenhouses gases, which leads to an increase in the Earth’s temperature. A greenhouse gas is an atmospheric gas that absorbs infrared light. Key greenhouses gases include: • carbon dioxide (CO2) • methane (CH4) • water vapour (H2O) • nitrous oxide (N2O)

  10. Carbon dioxide is released when fuels like gas, coal, oil, petrol and wood are burned. Greenhouse gases cause the temperature of the Earth to rise slowly. This causes climate change. Methane released from cattle and rice fields is also a greenhouse gas. Global warming Most fuels contain carbon Carbon dioxide released when fuel burned Extra carbon dioxide in the air slows down heat loss from Earth Climate change

  11. What is the carbon sink? Before the industrial revolution, carbon dioxide levels were usually kept in check by the carbon sink – forests and oceans that capture and store carbon. • forests –All green plants absorbcarbon dioxide as part ofphotosynthesis. The absorbed carbonis only released back into the atmosphere when the plant dies and rots, or is burned. • oceans–Carbon dioxide dissolves insea water, depending on the temperatureand pressure. Tiny marine animals calledphytoplankton extract carbon from the carbon dioxide to make their skeletons and shells.

  12. The carbon sink

  13. Deforestation Deforestation can have a contributing effect on global warming. Large scale deforestation (especially in tropical areas) has led to an increase of carbon dioxide in the atmosphere (when trees die they release their CO2) It has also reduced the amount of CO2 that is removed from the atmosphere Leads to loss of biodiversity. some organisms lost may have been needed in the future!

  14. Preventing global warming • Energy efficiency means less fuel burned to make electricity. • Fuel cell buses. • Renewable energy sources like water power, solar, wind farms, bio fuels. • Nuclear power. • The Kyoto agreement to reduce CO2 emissions. • Reduction in large scale deforestation

  15. Exam Questions Give one reason why deforestation increases the carbon dioxide concentration of the atmosphere. (1 mark) Explain, as fully as you can, why the increasing concentration of carbon dioxide in the atmosphere is causing global warming.

  16. Objective • How does combustion affect the atmosphere? • Success Criteria • By the end of the lesson I: • know how combustion affects the • atmosphere • know how living organisms affect the • atmosphere • can explain the consequences of global warming

More Related