Greenhouse Gases, Feedbacks, and Scenarios

What is the relationship between greenhouse gases and global climate change? 

Imperfect understanding of climate feedbacks is a major cause of uncertainty and concern about global warming.  How can the use of climate models help in the understanding of these uncertainties? 

With regards to the six emission scenarios, describe any evidence existing today that would suggest to you one or more of the scenarios may occur within the next 100 years.  What key uncertainties (climate forcings and feedbacks) would exist for these scenarios as a whole, or specific ones individually?

There are several gases which contribute to the greenhouse effect.  These gases are water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs).  These gases together contribute to what is known as the greenhouse effect.  The greenhouse effect occurs due to warming that results when the atmosphere traps heat radiating from Earth towards space.  This heat is trapped by the previously mentioned greenhouse gases.  The trapping of this heat causes a warming of temperatures on earth.

There are several climate feedbacks which we do not understand completely.  These include: Atmospheric factors (clouds and aerosols), Hydrosphere, Cryosphere, Lithosphere, and Biosphere.  Climate models can help us to understand these better by allowing us to simulate the change in each of these over a given period of time.  While a model may not be completely accurate, it can provide us with a possible scenario for the future.

Out of the six emission scenarios, I believe that scenario B2 is the most likely to occur within the next 100 years.  I believe this to be the most likely scenario due to the constant population growth without decline, and the emphasis on local, rather than global solutions to economic, social, and environmental stability.  The key uncertainties which will exist for all of the scenarios are atmospheric factors, hydrosphere, cryosphere, lithosphere, and biosphere.  I believe that these uncertainties would have the least impact on scenario A1T, which puts an emphasis on non-fossil energy sources.

Climate Forcings and Feedbacks

Which climate forcings and feedbacks are most prevalent in either your local area or in the United States as a whole and why might this be so?  What resources have you located to help you and your students understand climate forcings and feedbacks?

I think that aerosols, smoke, and soot are probably the most prevalent climate forcings in the United States and in my local area.  Due to industry and manufacturing, which is very important to the economy in Ohio, smoke and soot are put into the atmosphere.  Many people also use some type of aerosol daily without realizing the negative impact that they have on global climate change.

In exploring the readings and resources for this week's session, I found many resources which I believe would be helpful to my students in understanding this sometimes hard to grasp topic.  My favorite, and what most helped my understanding was the NASA Climate Time Machine.  This allows students to see the impact of global climate change in a way they can understand and in a time period that seems relevant to them.  Most high school students don't care how global climate change will effect the world in 2000 years - they want to see how it will impact them.

I also found the Greenhouse Effect simulation to be very helpful and I believe it would also be very helpful to students.  Future Global Warming Impacts by Region would also be beneficial because students could see exactly how global climate change could effect them where they live.  I also believe that the videos would be beneficial to show students at the beginning of a global climate change unit in order to get them thinking about the impact of it.