Atmospheric Carbon: Can We Offset the Increase?
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
Higher order thinking skills goals for this activity
- Problem solving
- Analysis of graphs
- Reflection on societal concerns
Other skills goals for this activity
Description and Teaching Materials
- Student Worksheet for Atmospheric Carbon Activity (Microsoft Word 130kB May18 13)
- Answer Key for Atmospheric Carbon Activity (Microsoft Word 2007 (.docx) 119kB May18 13)
Teaching Notes and Tips
Most students will have forgotten the formula for the volume of a sphere, but usually one or two will remember and can be encouraged to share.
Because my students are mostly from Maine, the worksheet uses this location as an example where reforestation could occur. It's not a very good example, since Maine is already about 90% forested. Instructors may wish to substitute another place in this part of the exercise. Nowak et al. (2013; see link below) provide carbon uptake estimates for urban tree planting; the IPCC report (link below) provides uptake ranges for boreal, temperate, and tropical forests.
After the activity, I like to show a website offering carbon offsets through tree planting (find these by searching for "buy carbon offset".)
Besides showing that reforestation cannot offset anthropogenic emissions of CO2, the activity could also prompt a class discussion on the climatic feedbacks associated with tree planting and changes in land cover (see Caldeira et al. link below).
References and Resources
Watson, R. T. (2000). Land use, land-use change, and forestry: a special report of the intergovernmental panel on climate change. Cambridge University Press. Online: http://www.ipcc.ch/ipccreports/sres/land_use/index.php?idp=151
To update graphics:
- Most recent Mauna Loa monthly data: http://scrippsco2.ucsd.edu/data/in_situ_co2/monthly_mlo.csv
- Most recent South Pole Observatory monthly data: http://scrippsco2.ucsd.edu/data/merged/monthly_merged_spo.csv