Mitigation Strategies What and Why?

What is mitigation? To decrease force or intensity. To lower risk. Earthquake mitigation Flood mitigation Climate change mitigation Some official definitions of mitigation: To moderate in force or intensity, to alleviate. To lessen in force or intensity. Elimination or reduction in frequency, magnitude or severity of exposure. To minimize risk. An informal definition that could be used to discuss the idea: Basically to make something that could be very bad less bad. Ask for examples of things people do to “mitigate” for the following environmental effects: Earthquake – build houses to building codes, try to get people to have emergency kits, meeting points. Floods – build houses on stilts, make walls so the water can’t get in. Create dams. Climate Change – mostly involve decreasing the amount of greenhouse gases of all kinds in the atmosphere. For the most part, mitigation cannot reverse warming that has already occurred, it can only slow or stop what would come without any changes.

This is what we know about CO2 concentrations over the past 50 years Image created by Robert A. Rohde / Global Warming Art This is a famous graph called the Keeling Curve. Charles David Keeling started measuring CO2 levels at the Mauna Loa Observation Laboratory in Hawaii in 1958. This graph shows only atmospheric carbon dioxide concentrations (not any other greenhouse gases). The annual cycle is due to changes in photosynthesis and respiration depending on seasonal fluctuations. The basic idea here is to show that CO2 concentrations are increasing.

Towards Stabilizing CO2 How? Why? What can we do? We can’t just stop emitting CO2 immediately We actually need to bring emissions significantly lower than current levels in order to stabilize concentrations of CO2. These diagrams are a first introduction to the mitigation wedge strategy used as a final assessment. It shows historical emissions and then the amount that we need to decrease emissions in order to avoid doubling or tripling CO2 concentrations over time. The flat path shows where we need to go to avoid doubling CO2 values. However, we actually need to bring emissions to lower than current values in order to decrease actual CO2 concentrations. Bringing CO2 values down this far will require a significant investment of money and resources. When we do the final assessment, students will be working in groups to make choices about how to decrease our total carbon emissions. Ask students for ideas since they just finished the wedge activity and should have ideas about sources, sinks, what is happening. Notes at top to help remember questions: HOW CAN WE DECREASE CARBON EMISSIONS? WHY DO WE WANT TO? WHAT CAN WE DO? Towards Stabilizing CO2

This graph shows the carbon emissions for several different types of power generating plants in Japan, Sweden and Finland. Looking at the graph it is clear that carbon emissions are far lower in alternative and renewable energy sources (solar, wind, nuclear, and hydroelectric) The idea here is that one potential mitigation would be replacing high carbon emitting plants (coal and gas) with lower producing carbon plants. Three of these (SOLAR, WIND AND NUCLEAR) are options in the final assessment project (The Wedge Activity).

One way to decrease carbon emissions? Replace fossil fuel burning power plants… …with lower or carbon free alternatives, like solar, wind, or nuclear energy. When students do the final assessment, they will need to think about the trade offs, so this would be a good time to start thinking about why we would make some choices over another. They will be thinking about some of these ideas and greenhouse gases for their concept maps tonight. Ask them if they have any ideas? They might already know about the higher cost of some other sources of energy or about how sometimes there is no sun or wind, but we still need electricity. There are some trade offs when replacing fossil fuel burning plants with other types. Increased cost. Ease of getting fossil fuels. Some alternative energy sources are not always available – such as wind or sun! How else can we generate energy or electricity? TRADE OFFS?

Carbon Dioxide Methane Nitrous Oxide About 99% of the total global warming potential for all new emissions comes from three main gases: Carbon Dioxide Methane Nitrous Oxide Image created by Robert A. Rohde / Global Warming Art I am wondering if this slide should come out. I think that the teacher can direct the discussion using the other slide just as well. This graph is from The GAS Files and shows annual emissions per sector. The emissions are mostly anthropogenic (human causes) especially Carbon Dioxide. Use it if you think your students could benefit from more discussion of the sectors and where the emissions come from.