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Things to Know about Climate
Tips 4 Teachers
A. Quantities
An estimation of how much the temperature will rise, given that CO2 stabilizes at a certain level of ppm given by the six colored bands in which CO2 stabilizes at different levels over time.
The distribution of greenhouse gases and their sources. Note that there are 14 greenhouse gases, but these three make up 99% of the total output.
A history of the previous Ice Age temperatures. These cycles are due to subtle changes in the Earth's orbit.
Taken from the 2007 IPCC report, these graphs show what the IPCC believes is required to reach a specific equilibrium GHG level (on the left, in Gigatonnes of CO2 per year) and what the corresponding temperature change will be (on the right)
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From the 2007 IPCC report, displaying the behavior of GHG emissions (left) and temperature change over the next century.
A collection of possible future CO2 equilibrium levels and their possible temperature changes.
B. Structures – laws, regulations, arrangements
C. Stakeholders (individuals, organizations, interest groups)
A. Quantities
- The total mass of atmospheric CO2 is approximately 3,000 gigatonnes. In the year 2004, the amount of CO2 released only by burning fossil fuels was 27 gigatonnes, not taking into account deforestation and other man-made sources. On the whole, anthropogenic sources of CO2 are not even 5% of the total emitted by the natural systems on Earth, but all of those natural systems have a corresponding way of reabsorbing what is produced. However, man-made CO2 does not have such a corresponding sink for CO2, so it is gradually increasing the concentration in the atmosphere.
- A methane emission will have 25 times the impact on temperature of a carbon dioxide emission of the same mass over the following 100 years. Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years).
- The "natural" level of CO2 in the atmosphere during the thousand years before humans started burning fossil fuels was approximately 280 ppm (parts per million).
- Since then, carbon dioxide levels have been rising at a steady rate. In 1960, for instance, the CO2 level was 313 ppm and now it's at 384 ppm (2007).
- There are many things that we don't know about how the climate will react to a continuing rise in greenhouse gas levels. Even if greenhouse gas levels stop going up, we don't know how long, if at all, it will take for the temperature to stop rising because the greenhouse gases already in the atmosphere continue to warm the planet year after year for hundreds of years.
- The IPCC's best estimate as of 2007 on how much temperatures would rise in the 21st century is between 2 and 4 degrees Celsius (3.2* - 7.2* F).
- Over the past 55 million years, the climate has gone from the hottest period since the extinction of the dinosaurs to the coldest. Beginning with CO2 levels at 3800ppm (ten times the current concentration), there was a sharp drop to 600, followed by a period of high fluctuation, which eventually settled into a gradual cooling trend. The culmination of this trend was three million years ago, when the first in a series of glacial expansions occurred in cycles, and has continued until 10,000 years ago, when the last glacial period ended. See Attachment at bottom of page (Climate Change Lite.ppt) for a history of CO2 levels.
- The melting of the polar ice caps could accelerate global warming as Antarctica, Greenland, and the Arctic Ocean will absorb more heat if they are dark ground or water rather than white ice.
- Warmer oceans might also amplify climate change. Cold water holds more dissolved gases than warm water. As the oceans warm up, they will absorb less CO2 and release more of the existing dissolved CO2, increasing the greenhouse effect, causing water temperatures to rise further.
- On the other hand, there is also a possibility that higher levels of CO2 will increase plant growth, causing more CO2 to be pulled out of the air, and helping to slow the greenhouse effect. (There is considerable scientific disagreement about whether this will occur and how large its effect will be, since an increase in plant growth also depends on less predictable factors like shifting rainfall patterns and changes in agriculture.)
An estimation of how much the temperature will rise, given that CO2 stabilizes at a certain level of ppm given by the six colored bands in which CO2 stabilizes at different levels over time.
The distribution of greenhouse gases and their sources. Note that there are 14 greenhouse gases, but these three make up 99% of the total output.
A history of the previous Ice Age temperatures. These cycles are due to subtle changes in the Earth's orbit.
Taken from the 2007 IPCC report, these graphs show what the IPCC believes is required to reach a specific equilibrium GHG level (on the left, in Gigatonnes of CO2 per year) and what the corresponding temperature change will be (on the right)
.From the 2007 IPCC report, displaying the behavior of GHG emissions (left) and temperature change over the next century.
A collection of possible future CO2 equilibrium levels and their possible temperature changes.
B. Structures – laws, regulations, arrangements
- http://www.epa.gov/climatechange/policy/index.html-- A list of US EPA climate policies and potential actions to mitigate and adapt to climate change
- http://en.wikipedia.org/wiki/Environmental_policy_of_the_United_States -- A useful summary of the history and current legal system concerning environmental action in the US.
C. Stakeholders (individuals, organizations, interest groups)
- Producers of fossil fuels (natural gas, oil, and coal): While they have no problem with sequestration other than its cost, and they are actively looking for ways to reduce greenhouse gas emissions, they would rather not lose money by reducing their use and selling less to consumers.
- Producers of other energy (hydro, nuclear, solar, wind, other non-carbon renewables): High increases in the value of these systems will occur if the government acts to reduce CO2 emitting processes.
- Farmers and ranchers: Changes in temperatures, wind, and rainfall can strongly alter the profitability of farming or raising animals.
- Consumers: Government action, such as emission regulations, energy use, taxes, or subsidies, will affect the economy because of how dependent our economic system is on fossil fuels.
- Homeowners in coastal and other low-lying areas: Rising sea levels could cause massive property damage, and weather patterns could worsen, causing a higher likelihood of hurricanes striking coastal settlements.
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Climate change lite.ppt (Powerpoint Presentation - 190k)
posted by MKauffman Oct 4 2008, 3:52 PM EDT
A history of CO2 levels over the past 50 million years
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