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Slides adapted and edited from: © National Wildlife Federation, 2007 What is global warming? How Global Warming Works Pollutant gases trap heat from leaving 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. Why is global warming happening? Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons (CFCs) Some of these come from natural sources, but many come from human (anthropogenic) activities The main sources of greenhouse gases are: Water vapor: • Can be produced from the evaporation of liquid water or from the sublimation of ice. • Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. • Water vapor is lighter than air and triggers convection currents that can lead to clouds. The main sources of greenhouse gases are: •Carbon dioxide: • Naturally found in our atmosphere, it is given off by organisms during cellular respiration. – Burning of fossil fuels and deforestation leads to higher CO2 concentrations. – Land use change (mainly deforestation in the tropics) account for up to one third of total anthropogenic CO2 emissions. Burning of Fossil Fuels Pollution from coal, natural gas, and oil The main sources of greenhouse gases are: Methane: • naturally produced by Livestock (as digestive gas) and manure. • Wet muddy areas are ideal for methanogenic bacteria, so rice paddy farming, land use and wetland changes contribute to CH4 levels. • Sewage gases and vented landfill emissions leading to higher atmospheric concentrations of CH4. The main sources of greenhouse gases are: Chlorofluorocarbons (CFCs) • Used in refrigeration systems (freon gas) • Used in fire suppression systems and extinguishers (halon gas). • Aerosol accelerants (gas in spray cans) The main sources of greenhouse gases are: Nitrous oxide • Agricultural activities, including the use of fertilizers, that lead to higher N2O concentrations. 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. A Correlation? Changes in Weather Patterns • Water temp changes combined with Warmer atmosphere throws off earth’s weather patterns! • Expect more frequent and severe droughts, floods, and hurricanes • Another example: – El Niño Southern Oscillation (ENSO), results from a series of interactions between the atmosphere and the tropical ocean. – It has been hypothesized that global warming trends may increase both the frequency and duration of ENSO events. – Since 1976, there have been seven El Niños. Based on the most reliable records, which go back 120 years, we would have expected to see only five. Severe weather events • There also seems to be an increase in the frequency and severity of HURRICANE activity that correlates to climate change • Katrina, 2005 • Elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems. • Projected to impact various issues such as freshwater resources, industry, food and health. Effects of Global Warming Rising Sea Level Increased Temperature Habitat Damage and Species Affected Changes in Water Supply Excessive precipitation occurs in some places… …while in other places, too little precipitation is causing problems Desertification: conversion of semiarid land to desert 19 Deforestation • Less precipitation and warmer air temperature dries out the soil, making it difficult for vegetation to grow. Borneo map: Negative Impact on Biodiversity Recent studies show that atmospheric CO2 is being absorbed into the oceans, etc, making them more ACIDIC. This kills plankton, among other things. How might this affect the oceanic ecosystem? 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 When did global warming start? Global Atmospheric Concentration of CO2 Human population growth How is global warming measured? Ice Core Data CO2 Measurements Before 1958 - Antarctica Ice Core Data Graph of CO2 (Green graph), temperature (Blue graph), and dust concentration (Red graph) measured from the Vostok, Antarctica ice core as reported by Petit et al., 1999. Higher dust levels are believed to be caused by cold, dry periods. CO2 Atmospheric Measurements CO2 Measurements Since 1958 – Mauna Loa, Hawaii 1000 Years of CO2 and Global Warming Temperature (Northern Hemisphere) Year Year 2000 1800 1600 1400 1200 1000 2000 1800 1600 1400 1200 1000 Parts Per Million Degree Celsius Increase CO2 Concentrations April 2009 in the news: • Here’s an inconvenient truth: A bridge to the Wilkins ice shelf, an Antarctic peninsula the size of Jamaica, has shattered. • Scientists think the shelf is now on the brink of breaking away, a development that could be a direct effect of global warming in this part of Antarctica. • Temperatures in Antarctica have risen up to 5.4 degrees Fahrenheit in the past 50 years, and shattering ice there has a big effect on sea levels worldwide. • Read it at BBC News Projections 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 and 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? Compact Fluorescent •1,430 lbs. CO2 pollution avoided •$30 saved 75% less energy used, lasts 10 x longer 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. © National Wildlife Federation, 2007