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  <li class="active"><a href="#energy" data-toggle="tab">Energy Balance Model</a></li>
  <li><a href="#carbon" data-toggle="tab">Carbon Cycle Model</a></li>
  <li><a href="#tutorial" data-toggle="tab">Model Info</a></li>
  <li><a href="#terminology" data-toggle="tab">Terminology</a></li>
</ul>
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    <p>How can we tell how temperatures, sea level and other properties will change in the future? We can use a climate model.</p>
    <p>At the heart of a climate model is the conservation of energy: if more energy comes into the climate system and goes out, then temperatures must go up. On the other hand if more energy goes out of the climate system than goes in, then temperatures must go down.  If the sun were to become stronger, then the incoming solar energy would increase and temperatures would rise. If albedo increases or the concentration of aerosols goes up then more solar energy is reflected away the temperature would go down. If the concentration of greenhouse gases increase then the greenhouse effect would get stronger and more heat energy would be directed to the surface, so temperatures would rise. In addition to direct warming or cooling as a result of different forcing, feedback processes can amplify or suppress the effect an initial warming or cooling. These feedback processes must also be built into a energy balance model.</p>

    <p><strong>How does it work?</strong></p>
    <p>Climate  models requires certain inputs and will produce a variety of outputs. The primary inputs to the model are:</p>
    
    <ul>
      <li>CO2 emissions (no. of billions of tons of CO2 released into the atmosphere each year – primarily through burning fossil fuels)</li>
      <li>CH4 emission</li>
      <li>Human aerosol emissions</li>
      <li>Volcanic aerosol emissions</li>
      <li>Energy reaching the earth from the sun (solar radiation)</li>
      <li>In addition we can modify the albedo of the planet </li>
    </ul>

    <p>Only the solar radiation  input is expressed as an energy (and so can be used directly by the Energy Balance Model). We still need to do some work with the other inputs to calculate what they correspond to in terms of energy into or out of the climate system.</p>

    <p>To tell us how changes in CO2 emissions change the energy into out out of  the climate system we need to use a Carbon Cycle Model.</p>
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    <h4><strong>Carbon</strong></h4>
    <p>A carbon dioxide model is used to figure out the concentration of co2 in the atmosphere. As we emit co2 through (by burning fossil fuels etc.) atmospheric co2 concentrations go up. But not all the co2 remains in the atmosphere.  some of it is absorbed by plants via photosynthesis. The carbon is stored in the vegetation or transferred to the soil. Decomposition of vegetation and processes in the soil can also release co2 back to the atmosphere.</p>
    <p>Additional atmospheric co2 is also absorbed by the ocean (causing ocean acidification). The rate of absorption depends on the level of acidification (more acidified water absorbs less co2) and water temperature.</p>
    <p>The strength of the greenhouse effect (i.e. the radiative forcing/energy) increases or decreases with higher or lower CO2 concentrations.</p>

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    <h4><strong>Methane</strong></h4>
    <p>A simple methane model is used to calculate the concentration of methane. Emissions of methane (from waste processing, agriculture etc.) increases the atmospheric concentration of methane. But atmospheric methane also gradually converts to other chemicals via oxidation.</p>
    <p>The strength of the greenhouse effect (i.e. the radiative forcing/energy) increases or decreases with higher or lower Methane concentrations.</p>
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    <h4><strong>Model outputs</strong></h4>
    <ul>
      <li>Surface temperature</li>
      <li>Deep ocean temperature</li>
      <li>CO2 concentration/radiative forcing</li>
      <li>CH4 concentration/radiative forcing</li>
      <li>Anthropogenic SO2 concentration/radiative forcing</li>
      <li>Ocean acidity pH and aragonite saturation (important for understanding coral survival)</li>
      <li>Sea level</li>
    </ul>

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    <h4><strong>Tutorial</strong></h4>
    <ol>
      <li>Select a pre built emission scenario. These include RCP scenarios used by the intergovernmental panel on climate change and a number of other simple test scenarios.</li>
      <li>From the drop down menu you will be able to see the various model inputs associated with that scenario I.e. CO2 emissions, aerosol emissions etc.</li>
      <li>Select which of these inputs will change over the course of the experiment I.e. You can keep one or more of the inputs constant to isolate the effect of that input.</li>
      <li>Press the RUN button. This will set in motion the model. Many thousands of calculations will be done in the background in the energy balance, carbon cycle and methane models.</li>
      <li>Output variables will be available here. Toggle between different possible model outputs.</li>
      <li>For more advanced use you can create your own scenario ...</li>
    </ol>
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  <div class="tab-pane fade" id="terminology">
    <ul>
      <li><strong>Radiative forcing</strong> <a href="https://en.wikipedia.org/wiki/Radiative_forcing"><i class="glyphicon glyphicon-new-window"></i></a> - the change in energy entering the climate system resulting from a change in greenhouse gas concentration, aerosol concentration or changes in solar radiation. Measured in Jules per second per square meter (or W/m2).</li>
      <li><strong>W/m2</strong>: Units for energy flux, number of joules of energy hitting 1 meter square every second. E.g. if all the energy from a 10W light bulb were focussed onto a piece of ground 1m x 1m the energy flux would be 10W/m2. On average the earth receives abot 340W/m2 from the sun.</li>
      <li><strong>PgC/yr</strong></li>
      <li><strong>Greenhouse gas</strong>: A type of gas that allows the passage of sunlight (shortwave radiation) but absorbs heat energy (longwave radiation). The two most important greenhouse gases controlling climate change are Carbon Dioxide, and methane. Others include nitrous oxide and ozone. While water vapour is also a very important greenhouse gas, humans cant directly affect its concentration.</li>
      <li><strong>Geoengineering</strong>: Technological solution to avoid the effects of global warming. One proposed scheme is Solar Radiation Management (SRM) whereby the amount of solar energy reaching the planet is reduced. This may be done for example by continuously pumping aerosols into the upper atmosphere (the particles reflect away incoming solar energy). Another possible option would be to place orbiting sun shades around the planet to block some of the suns energy.</li>
      <li><strong>Forcing</strong>: any factor that effects global temperatures and the climate system in general. In the model we have control over the following forcings:
        <ul>
          <li><strong>Carbon Dioxide CO2</strong>: the most important greenhouse gas, primarily produced by the burning of fossil fuels and to a lesser extent deforestation. Long lifetime in the atmosphere ~100years?</li>
          <li><strong>Methane CH4</strong>: an important greenhouse gas produced by agricultural processes and waste disposal. Short lifetime in the atmosphere ~20years?
          Aerosols: particulate matter produced by the burning of fossil fuel, forest fires, volcanoes. Particles reflect away incoming solar energy (i.e. has a cooling effect on the planet). Very short lifetime in the atmosphere ~1yr.</li>
          <li><strong>Volcanic aerosols</strong>: produced during large volcanic eruptions.</li>
          <li><strong>Solar radiation</strong>: energy coming from the sun (also termed shortwave radiation).</li>
          <li><strong>Albedo</strong>: the reflectivity of the planet (0 – all incoming solar energy is absorbed; 1- all incoming solar energy is reflected back to space). Average albedo for the earth is about 0.3.</li>
        </ul>
      </li>
      <li><strong>Climate system</strong>: The thin sliver at the surface of the earth made up of the atmosphere, the ocean, the cryosphere (ice sheets and glaciers) and the land surface.</li>
      <li><strong>Greenhouse effect</strong>: energy from the sun (shortwave radiation) warms the earth surface. The warm earth radiates heat energy (longwave radiation) outwards. Greenhouse gasses absorb much of this outgoing heat and re-radiates it in all directions (both upwards and downwards). The downwards directed energy represents an additional source of incoming heat energy that also warms the surface. This additional warming is the greenhouse effect. Adding additional greenhouse gases to the atmosphere will increase the greenhouse effect.</li>
      <li><strong>Long wave radiation</strong>: also called infrared radiation or heat energy. This is the type of energy radiated by the earth’s surface and the atmosphere. Long wave radiation is absorbed by greenhouse gases.</li>
      <li><strong>Shortwave radiation</strong>: also called solar radiation (largely visible and ultraviolet light). This this the type of energy radiated by the sun. Shortwave radiation is not absorbed by greenhouse gases.</li>
      <li><strong>Feedback</strong>: if a forcing causes a warming of the the earth’s surface, feedback processes can act to amplify or suppress the initial warming. Many different positive and negative feedback processes operate in the climate system. If the atmosphere warms it absorbs more water vapour from the ocean. But water vapour is a greenhouse gas. So more of it increases the greenhouse effect causing additional warming: the positive ‘water vapour’ feedback. If a forcing acts to warm the earth’s surface, the surface will radiate more heat energy away ultimately stopping the warming: the negative ‘blackbody’ feedback.</li>
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