The Greenhouse Effect

1. The Greenhouse Effect

2. 1. What is the Greenhouse Effect? • Climate Change Basics.avi

3. Greenhouse Gases • chemical compounds in the atmosphere that trap heat • they retain a proportion of the sun’s heat through the greenhouse effect. • 5 major greenhouse gases: Gas% of Greenhouse Effect water vapour (H2O) 36-70% carbon dioxide (CO2) 9-26% methane (CH4) 4-9% ozone (O3) 3-7% nitrous oxide (N20) 2-6%

5. Greenhouse Gases Nelson Science 1. Water Vapour: • ~ 60% of GG • quantity of water vapour depends on the temperature of the atmosphere • they are connected through a positive feedback loop

6. 2. Carbon Dioxide • ~ 25% of GG • produced from natural and human sources • volcanic eruptions, burning fossil fuels, cellular respiration in plants and animals and decomposition • carbon sinks – oceans and plants that absorb carbon dioxide from atmosphere and store it in a different form

7. The Carbon Cycle

8. Processes in Carbon Cycle How CO2 is added to atmosphere: • Cellular Respiration – plants and animals breaking down glucose to release energy • glucose + oxygen → carbon dioxide + water 2. Decomposition – bacteria/fungi breaking down dead material/wastes • if O2 is present, the carbon combines with it to form CO2 3. Burning Fossil Fuels/Wood – combustion • fuel + oxygen → carbon dioxide + water 4. Volcanoes – release CO2

9. How CO2 is removed from atmosphere • Photosynthesis – plants using sunlight to create glucose • carbon dioxide + water → glucose + oxygen 2. Dissolving into oceans • carbon dioxide dissolves into water and forms carbonate ions and carbonic acid * trees and oceans are Carbon Sinks – absorb lg amnts of CO2 Acid Test The Global Challenge of Ocean Acidification.avi

10. 3. Methane • 1 molecule of CH4 traps 23 times more GG than 1 molecule CO2 • from plant decomposition in swamps and animal digestion 4. Ozone • acts as GG in troposphere when it combines with exhaust creating smog 5. Nitrous Oxide (ha ha ha) • 300 times more powerful GG than CO2 • from natural and human sources • released by bacteria in soil and water • released in emissions from cars and factories

11. Anthropogenic GG • GG always been part of our atmosphere • major increase in past 200 years due to human activity • called anthropogenic GG • CO2 – burning fossil fuels, deforestation • CH4 – agriculture, mining, landfills • N2O – animal feed and wastes, fossil fuels

13. Feedback Loops • the problem creates an effect that impacts the original problem Positive Feedback – effect increases original problem Negative Feedback – effect decreases original problem. eg. thermostat controls temp

14. Water Vapour Feedback • water vapour enters the atmosphere when the climate warms up. • it’s a GG, so causes the climate to warm up even more. • if the climate cools down, less water vapour forms and the climate cools further

15. Albedo Effect • % of radiation reflected by a surface • ice has a high albedo (reflects back most UV rays) • If Earth’s temp drops slightly, more ice forms. • reflects more of UV rays, and Earth’s tempdecreases even more • If Earth’s temp increases, more ice melts. • More UV rays are absorbed, and Earth’s temp increases more. • Nelson Science Draw a diagram/flow chart of postive and negative albedo

17. 2. Making Predictions About the Greenhouse Effect & Climate Change i) how will world’s climate change over next 100 years if greenhouse gas emissions are not limited? • Canadian Climate Impacts and Scenarios ii) how will these changes affect humans?

18. Meltdown: A Global Warming Journey • Meltdown A Global Warming Journey Part 1.avi