Introduction. We are beginning our look at Earth's changing climate (usually referred to as global warming) due to increases in the levels of greenhouse gases in the air from human sources. The greenhouse gases are those that absorb infrared (heat) radiation and so interfere with that radiation travelling out into space. Although the overall amount of these gases in the atmosphere is small (less than 1%) they keep Earth warm enough for life. Because our civilization adds to the natural levels of these gases, Earth's average surface temperature is rising.
There are many greenhouse gases: water vapor, carbon dioxide, methane, nitrogen oxides, chlorofluorocarbons. Of all these it is CO2 that is examined the most for its effects. Carbon dioxide from respiration is not the issue, since it comes from the carbon in our food, which came from the air originally as plants photosynthesized. In this way CO2 from animals breathing is automatically balanced by CO2 taken out of the air by plants.
Global warming is caused primarily by CO2 released when fossil fuels are burned to provide energy for our society. Since almost everything Americans use consumes energy in some form, and most energy we use (whether for transportation, electricity or for manufacturing) comes from fossil fuel burning, we contribute to global warming every minute of every day.
Part 1. Why be concerned with global warming? What effects can we expect? The answers depend on where, on how much, and how rapidly the temperatures increase. Remember that even a small increase in temperature represents a huge increase in the overall heat energy of the atmosphere.
1.1
Go to the website for the
National Geographic program
Six Degrees and answer the following questions
while watching the segment
1oC.
1. What effects can be expected when Earth's temperature rises 1 degree?
2. What is it about the climate change the planet is experiencing now that has never happened before?
1.2
Now answer the following questions while watching the segment
2oC.
1. What effects can be expected when Earth's temperature rises 2 degrees?
2. How are coral reefs like a "canary in a coal mine"?
3. Why is a 2 degree rise in temperatures called a tipping point?
1.3 Next, answer the following questions
while watching the segment
3oC.
1. What effects can be expected when Earth's temperature rises 3 degrees?
2. What happened in Europe in the summer of 2003?
1.4
Next, answer the following questions
while watching the segment
4oC.
1. What effects can be expected if Earth's temperature rises 4 degrees?
2. What would happen if the entire West Antarctic Ice Sheet collapsed?
3. Why would the drying up of major rivers be a major disaster?
1.5 Next, answer the following questions while watching the segment 5oC.
1. What effects can be expected if we allow Earth's temperature to rise 5 degrees?
2. Why could human society begin to break down?
1.6 Next, answer the following questions while watching the segment 6oC.
1. If nothing is done to slow the emission of greenhouse gases and this causes Earth's temperature to rise by 6 degrees, what effects can you expect to experience?
2. What past events in geological time are associated with a six degree change in climate?
1.7 Next, answer the following questions while watching the segment What We Can Do.
1. How much of our electricity goes into buildings?
2. List some ways that energy is wasted in the typical home visited in the video:
3. What is "vampire load" and how many power plants could be eliminated in the US without it?
4. In addition to slowing climate change, what advantages are there to conserving energy?
5. Where do Americans consume the second greatest amount of energy? What percent of global greenhouse gases?
6. What are the conflicts between rich and poor nations tied in with global warming?
7. How many tons of greenhouse has emissions have to be cut every year to keep worming under 2 degrees?
8. What is the average fuel efficiency of all cars? How many tons of greenhouse gas emissions would be saved by doubling this?
9. How else can we cut greenhouse gas emissions?
10. How much has the temperature gone up so far?
Homework: To begin calculating your carbon footprint, find out how much energy your family uses. This includes the amount of oil or other fuel you burn, the amount of electricity you use and the gasoline you put in your cars.
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