I love the link to the excel program that you can download. The excel program let's students see how the actions of their consumption at school can impact climate change.
This website has an excel spreadsheet that allows students to enter information about things done at their school and the impacts it has on their environment.
Many of the questions on the OGT are about reading and interpreting graphs. This graph is another great introductory tol to have the students first describe the data and then brainstorm possible causes for the data before allowing them to read the article.
This graph could be a good intoduction to the lesson. You could have students analyze the data and brainstorm on possible causes of the data. The article could be introduced later on in the unit because it spells out many of the causes of this data.