From Meteorology to Mitigation: Understanding Global Warming

Project #2: Crop Models


We have seen over the past two lessons that agriculture is one key area of societal vulnerability to future climate change, but the challenges are complicated to confront. The effects are likely to be differentially felt in various parts of the globe, with the tropical regions more likely suffering losses, and extra-tropical regions seeing gains, at least for moderate levels of warming and atmospheric CO2 enrichment. Adaptive measures can ameliorate losses and potentially even turn losses into gains. Thus, any solution will likely require some degree of mitigation and some degree of adaptation. Moreover, the regionally-disaggregated nature of impacts will require policies that allow for an equitable redistribution of food resources from regions that are likely to see gains to regions that are likely to see losses.

In this project, you will propose your own policy solution to deal with agricultural vulnerability to future climate change. You will make use of quantitative tools that we have introduced in this course to address climate change mitigation, assess agricultural impacts, and modify those impacts through adaptation.



For this assignment, you will need to record your work on a word processing document. Your work must be submitted in Word (.doc or .docx), or PDF (.pdf) format, so the instructor can open it.

In this project, you are in charge of drafting an international protocol for maintaining global food security in the face of projected climate change over the next century, through a combination of (1) climate change mitigation, (2) agricultural adaptation, (3) policies for redistributing food resources to where they are needed, and crop substitution.

You will find it useful to employ two applications we have used in this course thus far:

  1. this Excel Spreadsheet ("toy 0-D energy-balance model (EBM)")
  2. Global Warming Impacts on Cereal Crops Application. Also found at the bottom of this page

As you proceed to design your policy, please use the following assumptions and rules:


  1. Current yields are defined at 0°C warming and correspond to no net deficit or surplus. In the Agricultural application, current yields are graphically depicted as 4 units (bushels) of agricultural yield, so that, for example, a 25% increase in yields would be depicted as an increase to 5 units.
  2. Increased food demand due to projected population growth is partially offset by improvements in agricultural technology, more widespread allocation of land for agricultural use, and economies of scale. Thus, despite a projected increase in global population of over 70% during the next century, assume that you will be able to meet projected food demands if you achieve a 4% increase in agricultural productivity relative to the current yields. [This is a highly optimistic assumption].
  3. Assume that food needs (i.e., the projected 4% increase relative to the current yields) are similar in both the tropical and extra-tropical sub-regions. In reality, this is not exactly true, as developing nations that are currently unable to meet existing food requirements are predominantly found in the tropics.
  4. Assume that each crop contributes equally to the total production in each sub-region, and also that the tropics and the extra-tropics contribute equally to the total world production. This means that, for example, if you increase the tropical wheat production by 6%, this would cause the overall production in the tropical sub-region to increase by 6% * 1/3 = 2% and the total world production to increase by 2% * 1/2 = 1%. 
  5. Assume a mid-range climate sensitivity in establishing the relationship between CO2 concentration stabilization levels and global mean warming.
  6. In the Agricultural application, current global mean temperatures are defined as 0.8°C higher than the pre-industrial mean temperatures. You need to account for that when using the toy EBM, which measures net warming relative to the pre-industrial temperatures (at 280 ppm CO2 concentrations).  That is, you need to subtract 0.8° from the warming calculated by the EBM application for a given CO2 level.
  7. Because of the projected amplification of warming over the continental regions, we will make a conservative assumption that all land regions warm 25% more than the global mean. That is, for a given CO2 level, you need to increase the projected warming (after making 0.8°C correction) by 25%. 


  1. Your default scenario is business-as-usual CO2 emissions, which we will represent by stabilization of atmospheric CO2 at 700 ppm, and a capacity to fund adaptation efforts for each crop in each region. 
  2. As a policymaker confronted with the real world constraints, you face a trade-off in the resources available to fund mitigation and adaptation efforts. That is, for every 50 ppm units you attempt to lower the CO2 emissions below business-as-usual levels (700 ppm), you lose the ability to fund one adaptation effort, i.e., to employ adaptations for one crop in either the tropics or extra-tropics. Note that this set-up provides a floor of 400 ppm stabilization, since there are only 3 crops x 2 sub-regions = 6 total possible adaptation efforts. So, effectively, you are allowed a total of six (adaptation / 50-ppm mitigation) efforts.
  3. You can substitute up to one crop for another within each sub-region, the tropics and the extra-tropics, at no cost in terms of adaptation / mitigation efforts. For example, if corn yields show less decline than wheat yields in the tropics for a given climate scenario, you may substitute corn for wheat in meeting tropical food requirements.  The crop being used to substitute for another may be adapted first, at the normal cost of one adaptation / mitigation effort.
  4. You are allowed to transfer yields (including adapted yields)from one sub-region to the other but at a cost in terms of CO2 emissions: for each half unit of agricultural productivity to be transferred, the CO2 stabilization level is increased by an additional 50 ppm.  Thus, for example, you may theoretically use six adaptation efforts for each crop / subregion combination and transfer a half unit of excess yield from one subregion to the other, but without any mitigation efforts your CO2 stabilization concentration would be 750 ppm.  Note also that if you had computed your yields for 700 ppm but then rely on subregional transfer, you would have to recompute your yields to be valid at 750 ppm -- unless you also apply resources towards one 50-ppm mitigation effort, to bring CO2 back down to 700 ppm.
  5. In your final answer, global yields, as well as yields in each sub-region, must have increased by 4%.  If you find multiple scenarios that satisfy all the rules, discuss which of the scenarios you as a policymaker would prefer to implement.

Presenting your work

Please present your work as a formal report, divided into the following sections:

  1. Introduction (state the objectives here)
  2. Methods
  3. Results and discussion
  4. Summary and conclusions

If needed, you may also include an Appendix to show any extended calculations. Try to keep your report reasonably short (3 pages is a good length).

Submitting your work

  • Save your word processing document as either a Microsoft Word or PDF file in the following format: Project2_AccessAccountID_LastName.doc (or .pdf).
  • Upload your file to the Project #2 assignment in Canvas by the due date indicated in the syllabus.

Grading rubric

The instructor will use the general grading rubric for problem sets to grade this project. (Downloadable PDF)