1 Global warmingKey words: combustion, carbon dioxide, methane, deforestation
2 Rising levels of carbon dioxide. Why? starterRising levels of carbon dioxide. Why?At the moment the change isseemingly very smallat 0.060C per year
3 How does combustion affect the atmosphere? ObjectiveHow does combustion affect the atmosphere?Success CriteriaBy the end of the lesson I:know how combustion affects theatmosphereknow how living organisms affect thecan explain the consequences of global warming
4 Get the gas right Pollution problem Gas Global warming Carbon dioxide Acid rainSulfur dioxide and nitrogen oxidesHoles in the ozone layerCFCs (Chloroflurocarbons)
6 Draw a diagram and explain the ‘greenhouse effect’ Teacher notesThis four-stage animation can be used to illustrate the principles of the greenhouse effect. Students could be asked to consider the impact of rising greenhouse gases on the natural phenomenon of the greenhouse effect.
7 Atmospheric carbon dioxide The worry of rising carbon dioxide levels isthatif the earth warms up then the ice capswill melt causing sea levels to rise.There is no evidence of this happeningbut it would meanthat low lying areas will flood and partsof or even whole countries will becomesubmerged!Teacher notesThis graph was produced using data sourced from the Mauna Loa Observatory, Hawaii, courtesy of NOAA (the National Oceanic and Atmospheric Administration). More information about atmospheric gases is available at
8 Carbon dioxide levelsCarbon 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 producecarbon dioxidePhotosynthesis removes carbon dioxideMore rice fields and cattle have led toincreased levels of methane in theatmosphere.Increased levels of greenhouse gases(carbon dioxide and methane) maycause global warming as a result of theGreenhouse effectBurning fossil fuels (combustion),deforestation andflooding land for the construction of hydroelectric damshave all contributed to rising levels ofcarbon dioxide.Another greenhouse effect harming theenvironment is methane which is producedby 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)Teacher notesSee the ‘Climate Change’ chemistry presentation for more information on greenhouse gases, the greenhouse effect and global warming.methane (CH4)water vapour (H2O)nitrous oxide (N2O)
10 Global warmingMost fuels containcarbonCarbon 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.Carbon dioxidereleased when fuelburnedExtra carbon dioxidein the air slows downheat loss from EarthClimate 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 absorb carbon dioxide as part of photosynthesis. The absorbed carbon is only released back into the atmosphere when the plant dies and rots, or is burned.oceans – Carbon dioxide dissolves in sea water, depending on the temperature and pressure. Tiny marine animals called phytoplankton extract carbon from the carbon dioxide to make their skeletons and shells.
13 DeforestationDeforestation 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 atmosphereLeads to loss of biodiversity.some organisms lost may havebeen 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 QuestionsGive 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 How does combustion affect the atmosphere? ObjectiveHow does combustion affect the atmosphere?Success CriteriaBy the end of the lesson I:know how combustion affects theatmosphereknow how living organisms affect thecan explain the consequences of global warming