About Lesson 10

It is reasonable to conclude, from our previous examination of projected climate change impacts, that some sort of coordinated response is warranted. One potential response involves adaptation — changing our behavior in such a way as to mitigate the impacts of climate change on our lives and livelihood. In fact, given that there is likely substantial additional climate change already in the pipeline, and we are committed to some degree of additional changes in climate regardless of what measures are taken to curtail greenhouse gas emissions, we will have to adapt to some changes that are in store. In this lesson, we will examine what the key vulnerabilities are, and what adaptive measures might be taken to guard against them.

What will we learn in Lesson 10?

By the end of Lesson 10, you should be able to:

• Discuss the vulnerability to climate change across various sectors and regions;
• Summarize potential adaptive responses to climate change;
• Quantitatively assess certain adaptive responses (through analysis of crop models driven with present and future climate conditions); and
• Discuss the limitations of purely adaptive responses vs. climate change mitigation.

What will be due for Lesson 10?

Please refer to the Syllabus for specific time frames and due dates.

The following is an overview of the required activities for Lesson 10. Detailed directions and submission instructions are located within this lesson.

• Begin Project #2: Run crop models (for both tropical and extra-tropical environments) under present and climate change conditions using different variations in planting techniques/cultivar selection to develop possible strategies for dealing with climate change impacts on agriculture.
• Participate in Lesson 10 discussion forum 4: Impacts, Adaptation, and "Before the Flood"
• Read:
  • IPCC Fifth Assessment Report, Working Group 2
    • Summary for Policy Makers, p. 8-29
  • IPCC Sixth Assessment Report, Working Group 1 --  Summary for Policy Makers (link is external)
    • Climate Information for Risk Assessment and Regional Adaptation, and Limiting Future Climate Change, p. 23-31
  • Dire Predictions, p. 150-163

Questions?

If you have any questions, please post them to our Questions? discussion forum (not e-mail), located under the Home tab in Canvas.  The instructor will check that discussion forum daily to respond. Also, please feel free to post your own responses if you can help with any of the posted questions.

The challenge of confronting the impacts of climate change is often framed in terms of two potential paths that civilization might take: adaptation and mitigation. Mitigation involves reducing the magnitude of climate change itself and, as we will see in the final two lessons, can be subdivided into two alternative strategies: emissions reductions — dealing with the problem at its very source, and geoengineering — somehow offsetting the effects of greenhouse gas emissions.

Adaptation, by contrast, involves efforts to limit our vulnerability to climate change impacts through various measures, while not necessarily dealing with the underlying cause of those impacts. The reference to "our" in the previous sentence is critical, as adaptive measures typically only deal with impacts to human civilization; they do not and, indeed, cannot deal with impacts to ecosystems and our environment. Coral reefs, for example, are unlikely to adapt to the twin impacts of global warming and ocean acidification. A similar case can be made for other ecosystems and living things. At some level, such considerations call into question what we really mean by adaptation. If we were to see the collapse of major ecosystems such as coral reefs, we would in turn see the loss of the ecosystem services they provide — a potentially catastrophic loss for human civilization. We will consider such potential costs when we attempt to work out the economics of climate change in a later lesson.

Such considerations call into question whether we can indeed define our true adaptive capacity to climate change in a way that is divorced from the larger impacts on our environment. Nonetheless, let us for the moment consider adaptation and mitigation as two alternative but potentially complementary and certainly not mutually exclusive strategies for dealing with climate change.

Figure 10.1: The place of adaptation in response to climate change

Click for a text description of Climate Change flow chart.

This image is split into two sections; one inside a purple-lined box labeled "IMPACTS and VULNERABILITIES", and the other outside. There are five light-purple boxes on the outside: "Policy Responses" is the first one, which points to "MITIGATION of Climate Change via GHG Sources and Sinks" and "Planned ADAPTATION of the impacts and Vulnerabilities". "Planned ADAPTATION..." points to the purple-lined box. "MITIGATION..." which leads to "Human Interference". "Human Interference" connects to "CLIMATE CHANGE, including Variability". "CLIMATE CHANGE..." connects to the purple-lined box. Inside the box, there are four more light-purple boxes, each connecting to the next: "Exposure"→"Initial Impacts or Effects"→"Autonomous Adaptations"→"Residual or Net Impacts". The purple-lined box then points back to "Policy Responses". 

Credit: IPCC

The choice between adaptation and mitigation is in fact, in many ways, a false choice — we will most likely have to do both. As we have seen previously in this course, we are already committed to additional warming of perhaps as much as 1°C due to the greenhouse gases that we have emitted already — this is known as committed climate change. Aside from the possibility of controversial geoengineering measures (which we will discuss in our next lesson), we cannot mitigate that change. So, we must adapt to at least that amount of climate change.

A useful way to look at the level of vulnerability to climate change is considering scenarios that involve no response measures at all (i.e., no adaptation or mitigation), adaptation alone, mitigation alone, and a combination of adaptation and mitigation.

As is apparent from the above comparisons, much of the world would likely suffer extreme vulnerability to climate change in the absence of any mitigation efforts at all, regardless of what adaptive measures are taken. Yet, mitigation alone, for example limiting CO₂ concentrations to 550 ppm, would in the absence of any adaptive measures still result in great vulnerability, particularly in tropical and subtropical regions. However, a combination of adaptation and mitigation could reduce vulnerability to modest levels for most of the world.

We will talk about mitigation approaches in the final two lessons. For the rest of this lesson, we will examine adaptive strategies. We will focus on specific examples in the areas of coastal protection, water resources, and agriculture/food resources.

There are various potential measures we might consider taking in defending our coastlines against the threat of sea level rise. We might think of them as sequential steps that can be taken as rising sea level continues to encroach on coastal settlements. We are likely already committed to at least 0.3 m (i.e., roughly 1 foot) of global sea level rise, enough, as we've seen previously, to threaten increased coastal erosion along the east and gulf coast of the U.S., and to submerge low-lying island regions.

Figure 10.3: Protecting Communities from Rising Water.

Credit: Mann & Kump, Dire Predictions: Understanding Climate Change, 2^nd Edition
© 2015 Pearson Education, Inc.

The first step is to actively confront encroaching seas by building structures such as polders, which reclaim inundated coastal regions, and coastal defenses such as dikes, beach nourishments, etc., which provide an impediment to rising waters.  The United States Navy is considering walls to protect assets at the Washington Naval Yard and the U.S. Naval Academy.

When that is no longer adequate, one might move on to the next step — accommodating some degree of inundation. That might include building flood-proof structures, and floating platforms for agriculture, etc. The final step is retreat. It can involve managed retreating, such as the building of sea walls, and planned evacuation when no other options are available. The island nation of Tuvalu, threatened with imminent impacts from sea level rise, for example, has already arranged for retreat to New Zealand when necessary.

Let us perform a thought experiment. Recall the projected sea level rise for the next two centuries (see figure below). Let us consider the gray region to represent the region of 95% confidence. Suppose you are an owner of a coastal property in a location where sea level rise is predicted to follow the projected global mean rise. Suppose that at 0.3 m sea level rise you can expect significant erosion of your beachfront, at 0.5 m of sea level rise you can expect regular flooding of your property from coastal storms, and at 1 m of sea level rise you can expect the front stairs to your house to be below sea level.

Figure 10.4: Projections of future global sea level rise ranging over the various IPCC scenarios, based on semi-empirical projections.

Credit: The Copenhagen Diagnosis

We saw in our previous lesson on climate change impacts, that anthropogenic climate change could profoundly influence freshwater availability around the world.

Figure 9.13: Shifting Water Resources [Enlarge].

Click Here for Text Alternative for Figure 9.13

• Serious Negative Impacts: The negative impacts of changing precipitation patterns outweigh the benefits. For example, the increases in annual rainfall and runoff in some regions are offset by the negative impacts of increased precipitation variability, including diminished water supply, decreased water quality, and greater flood risks. There is hope, however, that in some cases, adaptations (e.g. the expansion of reservoirs) may offset some of the negative impacts of shifting patterns of water availability.
• More Frequent Extreme Drought Events: Climate model simulations predict that the spacing between consecutive extreme drought events (defined as once-in-a-hundred-years events) will decrease sharply in many regions by the 2070s for the "middle of the road" emissions scenario.
• Future Climate Change Impacts on Water
  • U.S. - A steady increase in the population of cities in desert climates such as Phoenix and Las Vegas is occurring at precisely the same time that drought conditions are worsening
  • South America - Aquifers will be depleted 75% by 2050. 
  • Southern Europe and the Mediterranean - Many arid and semi-arid regions, such as the Mediterranean and parts of Southern Europe, Southern Africa, and much of Australia, are likely to suffer from increased drought. Electricity production potential to hydropower stations may decrease by more than 25% by 2070.
  • Africa - The spread of disease will increase due to more heavy precipitation events in areas with poor water supplies and an overtaxed sanitation infrastructure. 
  • India - In many coastal regions there will be plenty of water, but it will be the wrong kind! A sea level rise of 0.1 m (0.3 ft) by 2040-2080 will threaten the fresh water supply. 
  • Bangladesh - Areas with increased rainfall and runoff will suffer from an enhanced risk of flooding. The impacts are likely to be especially harsh for regions like Bangladesh, which is already facing the pressures of rising sea level. 
  • Worldwide - More than 15% of the world's population depends on the seasonal melt of high elevation snow and ice for fresh water. The melting of glaciers and ice caps represent a serious threat. 

Credit: Mann & Kump, Dire Predictions: Understanding Climate Change, 2^nd Edition
© 2015 Pearson Education, Inc.

What, if any, measures could we take to adapt to these changes? Possible adaptations can, in fact, be found on both the supply side and the demand side.

Let us first consider some supply-side options. Freshwater could, for example, be transported from regions that are likely to see more precipitation to those likely to see less. The required transport (which costs both money and energy!) could be minimized by exploiting the fact that in many cases such regions are reasonably near to each other, e.g., tropical Africa (more runoff)  vs. South Africa (less runoff), or the Pacific Northwest (more runoff) vs. desert southwest (less runoff) of U.S., or Northern Europe (more runoff) vs. Southern Europe and Mediterranean (less runoff). Other possibilities involve greater exploitation of groundwater sources, though this faces the challenge of over-tapped aquifers, which is already a problem in the U.S.  Desalinization makes sense, particularly for coastal regions of the U.S., Australia, and the Mediterranean which are predicted to dry, and where a nearby saltwater source would help minimize transportation costs. Desalinization is currently highly expensive and extremely energy intensive, making it a prohibitive source of freshwater today. However, as water resources diminish and technology improves, it is possible that desalinization will become a more viable option in the future. See table below for other possible supply-side solutions.

What about the demand side? More efficient recycling of water and better conservation of water resources is an obvious approach. Both constitute what is often referred to as no regrets approaches — a concept we will encounter later in the context of climate change mitigation. Such actions not only cost us nothing, but they could, in fact, provide benefits, e.g., lower household water bills! Similarly, more efficient means of irrigation of crops could save water and provide other benefits as well.

Another possibility is the idea of tradable water access rights. This too has an analogy with climate change mitigation, since one approach that has been suggested for reducing carbon emissions is to allow individual companies limited numbers of permits for emitting and then letting them trade and sell them. The same thing could be done for rights to water resources. The idea behind this is that the efficiencies of the free market will, at least in principle, find the most cost-effective means of meeting water resource needs, since those with excess fresh water would be motivated to sell their valuable water rights to others willing to pay a premium for them.

We examined likely impacts on agricultural productivity (and livestock) in our previous discussion of climate change impacts. While on balance these impacts are projected to be negative (particularly in the tropics), there are adaptive measures that can be taken to mitigate the losses in agricultural productivity.

Possible agricultural adaptations include changing crop locations; for example, seeking out higher elevation environments and cooler microclimates. Adaptations also include changing crop rotation patterns and tilling methods; for example, so-called no-till agriculture keeps sub-surface soils cooler and wetter, which might mitigate the effects of warmer and dryer conditions. One can switch to crop varieties (or cultivars) that are better adapted to the changing weather patterns and climate, or amend planting schedules to adapt to shifting seasonal temperature and rainfall patterns. And perhaps as the final line of retreat in the adaptation process, one can change the choice of crops grown, for example, replacing wheat with sorghum as conditions become increasingly arid.

Let us consider the potential mitigation of losses (or maybe even gains) that might come from employing these agricultural adaptations. Let us make the simplifying, if perhaps overly optimistic, assumption of optimal adaptation. That is to say, let us assume that stakeholders operate with perfect information and take the most favorable possible adaptive measures in response to changing climate conditions. Under that assumption, things do not appear too bad, at least for moderate future warming.

Let us consider the predictions for varying levels of future warming and associated CO₂ increase (note that there is a direct impact of CO₂ fertilization in addition to the indirect climate change impacts from increasing CO₂). For 1-2°C warming, we can expect to see increased yields across crops in the extra-tropics, due, in large part, to longer growing seasons, and, with appropriate adaptations, the agricultural productivity could be enhanced even more, approaching 10% for rice and corn and 20% for wheat. For that same amount of warming in the tropics, however, cereal crop productivity either remains the same (rice) or declines (wheat and corn). However, appropriate adaptations can change the picture, turning declines into modest gains. On the global scale for the modest 1-2°C warming, agricultural productivity increases, largely due to the gains in the extra-tropics. However, even at this moderate level of warming, we begin to see the challenges of the regional asymmetry in agricultural productivity responses — the gains are primarily in the regions that are already able to meet food requirements (i.e., the developed world of the extra-tropics), and not in the regions faced by shortfalls owing to their lesser wealth and growing population (i.e., the developing world of the tropics). As warming increases beyond 3°C, this disparity becomes even greater, as low-latitude regions are likely to see agricultural productivity declines regardless of what adaptive measures are taken. For warming beyond 3°C, global agricultural yields decline even with adaptation, and global food prices show substantial increases. As warming approaches 5°C, losses are seen in the extra-tropics as well as in the tropical regions, regardless of the adaptive measures, and global agricultural productivity losses and food price increases become substantial.

Figure 10.5: Climate Change Impacts on Agriculture, Livestock and Fisheries.

Click Here for Text Alternative for Figure 10.5

Climate Change Impacts on Agriculture, liveswtock, and Fisheries

Temperature Change	Sub-sector	Region	Finding	Alleviation after adaptation
+1.0 to 2.0 Degrees Celcius	Prices	Global	Agricultural prices: -10 percent to -30 percent
+1.0 to 2.0 Degrees Celcius	Pastures and livestock	Semi-arid	No increase in productivity of plant growth; seasonal increased frequency of livestock heat stress
+1.0 to 2.0 Degrees Celcius	Food crops	Low latitudes	Without adaptation, wheat, and maize yields reduced below current levels; rice yield is unchanged	Adaptation of maize, wheat, and rice maintains yields at current levels
+1.0 to 2.0 Degrees Celcius	Pastures and livestock	Temperate	Livestock grazing less likely to be limited by length of growing seasons; seasonal increased frequency of livestock heat stress
+1.0 to 2.0 Degrees Celcius	Food crops	Mid to high latitudes	Crop growth less likely to be limited by length of growing seasons as well as no overall change in rice yield; regional variation is high	Adaptation of maize and wheat increases yield by 10 to 15 percent
+2.0 to 3.0 Degrees Celcius	Food crops	Low latitudes		Adaptation maintains yields of all crops above current levels; yields drop below current levels for all crops without adaptation
+2.0 to 3.0 Degrees Celcius	Pastures and livestock	Semi-arid	Increased frequency of livestock heat stress
+2.0 to 3.0 Degrees Celcius	Pastures and livestock	Temperate	Moderate production loss in swine and cattle
+2.0 to 3.0 Degrees Celcius	Fisheries	Temperate	Positive effect on trout in winter, negative in summer
+2.0 to 3.0 Degrees Celcius	Food crops	Mid to high latitude		Adaptation increases all crop yields above current levels
+2.0 to 3.0 Degrees Celcius	Prices	Global	Agricultural prices: -10 percent to + 20 percent
+2.0 to 3.0 Degrees Celcius	Food crops	Global		550 ppm CO with no adaptation increases rice, wheat, and soy-bean yields by 17 percent
+ 3.0 to 5.0 Degrees Celcius	Pastures and livestock	Semi-arid	Reduction in animal weight and pasture growth; increased frequency of livestock heat stress and mortality
+ 3.0 to 5.0 Degrees Celcius	Food Crops	Low latitudes		Maize and wheat yields reduced, regardless of adaptation; adaptation maintains rice yield at current levels
+ 3.0 to 5.0 Degrees Celcius	Pastures and livestock	Low latitudes	Strong production loss in swine and confined cattle
+ 3.0 to 5.0 Degrees Celcius	Prices and trade	Global	Reversal of downward trend in wood prices, Agricultural prices are up 10 to 40 percent, and Cereal imports of developing countries are up 10 to 40 percent.

Credit: Mann & Kump, Dire Predictions: Understanding Climate Change, 2^nd Edition
© 2015 Pearson Education, Inc.

Now, you will investigate these relationships in detail yourself, interactively, using a more elaborate version of the agriculture application you encountered in our previous lesson. The application now indicates changes in yields of major cereal crops (wheat, rice, and corn) both with and without adaptive measures. Please take some time to explore the agricultural application below. You will be using this tool in Project 2, which begins this week.

In this lesson, we looked at the potential impacts of projected climate change on civilization and our environment. The key points are as follows.

• Adaptation and mitigation are two often-discussed strategies for dealing with the threats and challenges of human-caused climate change. The two approaches are not mutually exclusive —it is very likely that both will need to be employed if we are to limit societal vulnerability to climate change.
• Adaptive measures to reduce coastal vulnerability to sea level rise take the form of three progressively more defensive responses to increasing magnitudes of sea level rise — protection through engineering, followed by accommodation to rising sea level and, eventually, managed retreat.
• There are a variety of adaptive responses that might be taken to deal with shifting water resources resulting from anthropogenic climate change. These responses take the form of demand side and supply side actions. On the demand side are better conservation of available freshwater resources (a so-called no regrets strategy), and introduction of a system of tradable water rights to help insure efficient use of available fresh water. On the supply side are the development of better distribution systems to move water from regions of surplus to regions of deficit, better use of available groundwater and freshwater aquifers, and (though currently not cost-effective) the use of desalinization technology, particularly in coastal regions where distribution requirements would be minimized.
• Adaptation can to some extent mitigate the loss of agricultural productivity due to climate change, though there are substantial differences between tropical and extra-tropical regions, and also between different crops (e.g., staple cereal crops such as rice, wheat, and corn/maize).
• Theoretical crop models subject to admittedly limited (and perhaps not wholly realistic) climate change scenarios of, e.g., simple warming of temperatures and elevation of CO₂ levels, indicate that for moderate warming, losses in tropical regions can be mitigated through the introduction of appropriate adaptive measures. Adaptive measures can further bolster agricultural increases in extratropical regions that benefit from longer-growing seasons with warming.
• The same crop models indicate that as the warming progresses, gains in the extra-tropical regions become increasingly less, and losses in the tropical regions become increasingly greater, even with appropriate adaptive measures. As warming approaches 5 °C, losses are seen in all regions regardless of adaptation, and both global food productivity declines and global food price increases become substantial.

Reminder - Complete all of the lesson tasks!

You have finished Lesson 10. Double-check the list of requirements on the first page of this lesson to make sure you have completed all of the activities listed there before beginning the next lesson.

Activity

Directions

Please participate in an online discussion of the material presented in Lesson 9: Climate Change Impacts; Lesson 10: Vulnerability and Adaptation to Climate Change; and the movie "Before the Flood".

This discussion will take place in a threaded discussion forum in Canvas (see the Canvas Guides for the specific information on how to use this tool) over approximately a week-long period of time. Since the class participants will be posting to the discussion forum at various points in time during the week, you will need to check the forum frequently in order to fully participate.  You can also subscribe to the discussion and receive e-mail alerts each time there is a new post. 

Please realize that a discussion is a group effort, and make sure to participate early in order to give your classmates enough time to respond to your posts. 

Post your comments addressing some aspect of the material that is of interest to you and respond to other postings by asking for clarification, asking a follow-up question, expanding on what has already been said, etc. For each new topic you are posting, please try to start a new discussion thread with a descriptive title, in order to make the conversation easier to follow. 

Suggested topics

The purpose of the discussion is to facilitate a free exchange of thoughts and opinions among the students, and you are encouraged to discuss any topic within the general discussion theme that is of interest to you.  If you find it helpful, you may also use the topics suggested below.   

"Before the Flood"

• What effect on our planet portrayed in the movie was the most shocking to you?
• Are there solutions presented in the film that give you hope or inspire you to action?  Why?
• How effective is the film in presenting the topic? In your opinion, what are the strongest and the weakest points of the film?

Lesson 9: Climate Change Impacts

• In your opinion, what are the most serious projected impacts of climate change?
• What do you think about the concept of "ecosystem services"? Is it ethical to apply cost/benefit analysis to Earth's ecosystems and biodiversity?
• Experiment with the interactive application "global warming impacts on cereal crops". Discuss how different crops are affected by various amounts of future projected warming, for both tropical and extratropical regions.

Lesson 10: Vulnerability and Adaptation to Climate Change

• Two strategies for confronting the impacts of climate change are adaptation and mitigation.  What is the difference between the two? Considering that climate change impacts are very non-uniform across geographic regions, in your opinion, which of the two strategies is more ethical? 
• Realistically, do we have a choice between adaptation and mitigation?  When is the time to start applying these strategies?
• What do you think of trading water access rights as an adaptive strategy for reduced freshwater availability?

Submitting your work

1. Go to Canvas.
2. Go to the Home tab.
3. Click on the Lesson 10 discussion: Impacts, Adaptation, and "Before the Flood".
4. Post your comments and responses.

Grading criteria

You will be graded on the quality of your participation. See the online discussion grading rubric for the specifics on how this assignment will be graded. Please note that you will not receive a passing grade on this assignment if you wait until the last day of the discussion to make your first post.

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.

Activity

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:

Assumptions:

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%. 

Rules:

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)