Global Warming and Climate Change What is global warming? A gradual increase in the Earth’s temperatures as a result of rising levels of carbon dioxide and other greenhouse gases in the atmosphere. How Global Warming Works Carbon Dioxide (CO2) Fossil fuels (coal, oil, natural gas) The Greenhouse Effect • Greenhouses can trap the sun’s rays because of their glass panels. This makes the inside of them warm. This is why in the winter they remain warm enough to be able to grow plants. The Greenhouse Effect • When the sun’s rays pierce onto the glass window of a greenhouse, the rays become weaker. Not all can pierce back through into the air. This causes the temperature inside the greenhouse to rise (get warmer). The Greenhouse Effect • When the sun’s rays pierce onto a window, they get “trapped.” The rays cannot all bounce back into the air. This causes heating of the area, which is known as the greenhouse effect. Example of the Greenhouse Effect The Sun’s energy passes through the car’s windshield. This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up. This Greenhouse Effect on Earth • A similar situation happens in the Earth’s atmosphere, but of course, no window is involved. • The greenhouse effect on Earth helps us understand temperatures of the Earth, as well as the recent increase in the Earth’s temperatures, known as Global Warming. • The Earth’s greenhouse effect involves the sun’s rays, the Earth’s atmosphere, and greenhouse gases which exist in the atmosphere. • Let’s see... The Greenhouse Effect on Earth There are a tiny number of gases (i.e. carbon dioxide, methane) found in the Earth’s atmosphere that when they sun’s rays are released, they absorb some of the heat before it can escape back into space. These are called greenhouse gases. The Greenhouse Effect on Earth Greenhouse gases are essential for all life on Earth. They help keep some heat (warmth) in the Earth. Without greenhouse gases, temperature on Earth would always be about 30ºC colder. It would be a cold and lifeless planet like Mars! The Greenhouse Effect on Earth We call them “Greenhouse Gases” because of the way they warm our Earth, very similar to how a greenhouse works as we saw in previous slides. How does this contribute to Global Warming? Greenhouse gases have been increasing due to human activities that cause pollution (i.e. the burning of fossil fuels) in our atmosphere. The increase of greenhouse gases cause the Earth to get HOTTER. The atmosphere becomes “thicker” and more heat gets absorbed by greenhouse gases, because less can escape from the thicker atmosphere. This makes the Earth warmer. This is called Global Warming. How does this contribute to Global Warming? Global Warming: Warming of the Earth’s temperatures due to a rise in greenhouse gases in the atmosphere. Effects of Global Warming • • • • • Rise in sea levels Chance in precipitation Forests, farmlands New parasites, new insect-borne diseases Droughts, flooding • http://www.youtube.com/watch?v=Z_jHP6xBLe 8 • http://youtu.be/n94lepehpm4 Assignment: • Making Connections Textbook – page 462 #1-3 What’s the difference between “global warming” and “climate change”? Difference GLOBAL WARMING is the increase of the Earth’s average surface temperature due to a build-up of greenhouse gases in the atmosphere. CLIMATE CHANGE is a broader term that refers to long-term changes in climate, including average temperature and precipitation. Effects of Global Warming Rising Sea Level Habitat Damage and Species Affected Increased Temperature Changes in Water Supply What’s the proof that global warming is taking place? Portage Glacier • Alaska 1914 Photos: NOAA Photo Collection and Gary Braasch – WorldViewOfGlobalWarming.org 2004 Colorado River • Arizona June 2002 Dec 2003 Why is global warming happening? Burning of Fossil Fuels Pollution from coal, natural gas, and oil When did global warming start? Global Atmospheric Concentration of CO2 How is global warming measured? Ice Core Data CO2 Measurements Before 1958 - Antarctica CO2 Atmospheric Measurements CO2 Measurements Since 1958 – Mauna Loa, Hawaii 1000 Years of CO2 and Global Warming Temperature (Northern Hemisphere) 2000 1800 Year 1600 1400 1200 1000 2000 1800 Year 1600 1400 1200 1000 Parts Per Million Degree Celsius Increase CO2 Concentrations Global Warming: Shifting Gears Billions of Metric Tons Carbon Goal: Reductions in 2007 CO2 Per Year of Metric Billions Carbon Tons Carbon Gigaton Our Goal 2007 Reductions in CO2 Per Year Produce electricity efficiently Use electricity efficiently Vehicle efficiency Solar and Wind Power Biofuels Carbon capture an storage What’s being done now to reduce our emissions? Wind Power Solar Power Fuel-Efficiency What can you do to help solve the problem? Simple Things To Do Turn off your computer or the TV when you’re not using it. Take shorter showers. Heating water uses energy. Keep rooms cool by closing the blinds, shades, or curtains. Turn off the lights when you leave a room. Use compact fluorescent bulbs. Be Bulb Smart—Use CFLs Incandescent What’s the difference? 500 lbs. of coal •1,430 lbs. CO2 pollution avoided •$30 saved Compact Fluorescent Simple Things To Do Dress lightly when it’s hot instead of turning up the air conditioning. Or use a fan. Dress warmly when it’s cold instead of turning up the heat. Offer to help your parents keep the air filters on your AC and furnace clean. Walk short distances instead of asking for a ride in the car. Plant a tree. Recycle.