Radiation Emitted from the Sun and the Earth The earth and the sun radiate as black bodies, that is, as a function of their temperature. If the earth did not have an atmosphere, the earth would be -1 F. The atmosphere serves as a blanket for the earth, allowing the earth’s surface to be an average temperature of 58 F. How does the atmosphere do this?

Resonance Frequency For a spring and weight, there is one frequency of vibration which will create a sustainable oscillation. For molecules, depending on their structure, there are one or more sustainable vibrations, or resonance frequencies. A vibrating molecule has more energy. This is perceived as an increase in temperature. The molecules in the atmosphere are effective absorbers of infrared (longwave) radiation because the resonance frequencies of many molecules in the earth’s atmosphere are in the infrared spectrum.

Properties of Greenhouse Gases (GHGs) Units Global Warming Potential Atmospheric Lifetime (yr) CO2 ppm 1 120 CH4 ppb 23 12 N2O 296 114 CFCs ppt 4,600 to 10,600 45-100 Water Vapor (H2O) Carbon Dioxide (CO2) Methane (CH4) Chlorofluorocarbons (CFCs) Let’s look at three factors which contribute to the effectiveness of particular greenhouse gases. 1. Relative abundance; 2. Absorptive properties relative to CO2; 3. Atmospheric lifetime. A note about CFCs: here is an example of human progress leading to a potential global catastrophe AND an effective global response which averted catastrophe. Climate Change 2001: The Scientific Basis . J.T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Da, K. Maskell, and C. A. Johnson for the Intergovernmental Panel on Climate Change.

Absorption Spectra of GHGs Water Vapor

Absorption Spectra of CO2 A note about CO2 absorption relative to water vapor’s absorption. Water vapor absorbs very effectively near the earth’s surface. As you go up in altitude, though, the concentration of water vapor falls off, whereas the concentration of CO2 is well-mixed high into the stratosphere. Thus, the CO2 can continue to absorb infrared radiation as the radiation is transmitted upward.

Absorption Spectra of CH4

Absorption Spectra of Major GHGs H2O, CO2, NO2, CH4

CO2 Concentrations Have Been Increasing Worldwide Two facts to consider when writing your position papers. 1. CO2 concentrations have been increasing worldwide over the last 45 years; 2. The level of rise is in step with world carbon emissions. Climate Change 2001: The Scientific Basis . J.T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Da, K. Maskell, and C. A. Johnson for the Intergovernmental Panel on Climate Change.

CO2 Concentrations Have Been Increasing Proportionally to Burning of Fossil Fuels http://cdiac.ornl.gov/trends/co2/siple.htm

CO2 Variability Over the Last 400,000 Years

Greenhouse gases have increased in the atmosphere in the last 250 years Carbon dioxide Methane Nitrous oxide Chlorofluorocarbon-11 260 280 300 320 340 360 290 310 600 1000 1400 1800 1750 1850 1900 1950 2000 Year 0.0 0.1 0.2 0.3 CO concentration CH concentration CFC concentration N O concentration 2 4 Overall human activity accounts for 75% of the increase in greenhouse gases

Mean global surface temperature has increased over the last 150 years 1870 1890 1910 1930 1950 1970 1990 Year Change from 1940 temperature (°C) -0.6 -0.4 -0.2 0.0 0.2 0.4

Kyoto Protocol The Kyoto Protocol is an agreement made under the United Nations Framework Convention on Climate Change (UNFCCC). Countries that ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or increase emissions of these gases. Adopted in 1997 Ratified by 165 countries globally Reduce collective emissions of GHGs by at least 5% from 1990 levels in the 2008-2012 time period. The Kyoto Protocol entered into force on 16 February 2005. A note about the current federal approach to greenhouse gas emissions: Greenhouse Gas Intensity = (GHG emissions (carbon equivalent))/real GDP So, if you reduce GGI by 18% (which I believe Bush has pledged), you don’t actually have to reduce GHG emissions at all – just find a way to increase GDP. That is, as long as you are increasing your productivity, you don’t have to decrease your GHG emissions. http://unfccc.int/essential_background/kyoto_protocol/items/2830.php

Bali Meeting Dec. 2007 Kyoto expires in 2012 What next? Proposed cuts 25-40% below 1990 levels for industrial nations. U.S. refuses cooperation Provisions for developing countries vs. industrial countries Debate over technology development & transfer Deforestation/reforestation