Sustainability and Social Justice

This essay is chapter 4 in the book Mathematics for Social Justice: Resources for the College Classroom edited  by Gizem Karaali and Lily S. Khadjavi (2019).  MAA Press: An Imprint of the American Mathematical Society.

Social Justice and Sustainability: Two Perspectives on the Same System

Jason Hamilton and Thomas J. Pfaff

The situation appears untenable: Humans live on a big rock floating in space about 93,000,000 miles from the nearest energy source. The reason this works, of course, is that we exist in a highly complex system of interconnected parts that function to keep us alive. We rely on plants and other organisms to construct our atmosphere, regulate temperature within livable bounds, capture energy from the sun to feed ourselves, purify our water, and make soil. Humans rely on each other for goods and services, security, love, and psychological and emotional well-being. In short, we live in a complex social-ecological system: On this earth, there are no natural systems free of human influence, and there are no social systems free from the influence of the rest of the biosphere [19].

Despite the inextricable interconnections among the human and non-human parts of our system, those of us who want to make the world a better place have tended to gravitate toward one side or the other. Social justice activists are concerned about economic, political, and social inequities among people. Environmental activists are concerned about environmental quality and the harmful effects of human activities. Given that our “life-support” system is, in fact, a social-ecological system, these two groups are ultimately working toward the same goal. Let us consider a simple analogy: A ship has hit an iceberg and is slowly sinking; on the ship a fire is burning and will soon hit the fuel tanks causing the whole ship to explode; a man on the ship is about to be murdered by a pirate. Which one of these issues is most important? Of course they all are equally important. Saving the man without putting out the fire is ultimately pointless. Stopping the ship from sinking does not help the man much if he is dead. Anybody who is trying to work to improve any part is working with everybody else to improve all the parts.

In many mathematics classes (as with most college courses in general), we tend to focus on a part of the system and seldom if ever discuss the social-ecological system as a whole. For example, it is easy to see how the tools of mathematics can be applied to climate change by considering temperature data sets, such as distributions of temperature changes across the planet, or working with simple climate models. It can be more difficult to consider the social effects of changing climate on human lives and well-being. Because of this difficulty, we mathematics instructors often shy away from the social part of the system and focus only on the model or the data. If we do choose to focus on a human issue, for example, by bringing into our classroom epidemiological data relating poverty to rates of childhood asthma, we often do not feel competent to use our mathematics to explore how this might be exacerbated or ameliorated by reinforcing or balancing feedback loops related to anthropogenic climate change.

Our goal in this essay is to demonstrate how mathematics can be used in the classroom to address linked issues in the social-ecological system that is the human life support system. First we show how the seemingly separate areas of social justice and environmentalism are brought together into a unified social-ecological system within the concepts of sustainability. Then we provide several examples of how to address the larger systems issues of sustainability in mathematics courses.

What is Sustainability?

How does the concept of sustainability help to overcome the false human/non-human dichotomy that humans have created? Despite the common conflation of sustainability with environmentalism, green purchasing, or energy management, it is a much richer concept. The meaning of the word sustainability is context-dependent. As shorthand for the term “sustainable development” [24], the concept of sustainability was developed as a new paradigm for improving overall human well-being by considering the coupled social-ecological system. Originally used only in the context of social change, sustainability explicitly referred to meeting the basic needs of all people and extending the opportunity to satisfy aspirations for a better life to everybody, with change being required in all countries, rich and poor alike.

What was the goal of sustainability? What was to be sustained? The sustainability of development itself. The point is that sustainable development is not a fixed endpoint or a steady-state condition of a group of variables with respect to time. Rather, it is a process of sustained change in which natural resource use, monetary investment, the orientation of technological development, and institutional change are consistent with future and present needs [23].

Given that the word sustainability is so often misused and abused it is no wonder that there is ambiguity in many people’s minds regarding the relationship between it and other concepts such as environmentalism or social justice. Ultimately, the real goal is to adopt a whole system perspective where the boundaries between social justice and environmentalism fade and we gain the richness of a new, more integrated perspective.

Sustainability starts with four simple propositions, any of which can serve as an entry point for a mathematics course. We explore these below.

Thesis 1: We can do better.

It is the best of times, it is the worst of times (apologies to Dickens). Humans are, on the whole, longer-lived, better nourished, more educated, and have a higher standard of living than at any other time in our history. At the same time, we certainly can, and must, do much better. Just look around: new and emerging diseases; climate instability; food and water insecurity; huge and growing wealth discrepancies; differential rates of poverty among different ethnic groups within countries; lack of access to quality education for many; and lack of gender equality [22]. Delineating these problems is not an indictment of our lifestyle or the decisions humans have made in the past. Rather, it is a realistic assessment that humans have come a long way and that we have a long way to go.

Thesis 2: We risk limiting the options of future generations.

It is clear to scientists that the collective decisions and actions of humans today are negatively impacting the ability of future generations to meet their needs and aspirations. Global climate change [13], ozone destruction [25], degradation of ecosystem services [11], peak oil [2], accumulation of persistent toxins in the environment [20], new and emerging diseases [12], and trends in food production [5] all point to the same conclusion: human impacts on the planet are accumulating at a rate that endangers our well-being. Unless we agree to consign our children and grandchildren to a world of very limited potential, we must include issues of inter-generational equity into our planning and decision making. How do we keep environmental degradation from nullifying our advances in human rights? How do we keep poverty from being a driver of environmental degradation? Why are we in a position to even have to ask this question?

Thesis 3: The system is not simply “broken”.

Given this complex and multifaceted set of issues, how does one work towards improvement without becoming overwhelmed by the enormity of the task compared to the size of the contribution that one person (or even a group of people) can make? Traditionally, we have tended to subdivide such problems into categories that do not seem quite so daunting. For example, environmentalists tend to focus on environmental issues: air pollution, water pollution, habitat destruction, endangered species, etc. Social justice activists tend to focus on a different set of issues: wealth distribution, privilege, institutional racism, gender inequality, etc.

This division of problems into distinct areas is deeply imbedded in our thinking and the mental models we use to make sense of the world. It is also reflected in the way we govern our societies. For example, in the United States, the Department of Health and Human Services is a different entity from the Department of Labor, the Department of Agriculture, and the Department of Housing and Urban Development. The Environmental Protection Agency is a different entity from the Council of Economic Advisors, the Department of Commerce, and the Department of Energy.

These distinctions and divisions in our thinking are also embedded in our educational system. In K-12 education, social studies and government is taught as a distinct area separate from science. Mathematics is taught as a separate discipline from everything else. Even when we look at data or models of real world phenomenon, mathematics instructors typically will not even mention ethical, philosophical, political, or other areas of implication or connectedness. As an example, climate change is not only a sci­entific issue but also an ethical issue in that the people disproportionately impacted by climate change are not the ones causing the problem or benefiting from activities and processes causing the problem.1
In higher education, Biology departments are separate from departments of Environmental Studies. Sociology is different from Psychology, which is different from Communication. The humanities are typically distinct from the social sciences, which are distinct from the natural sciences.

Perhaps a large part of the problem is the way we have chosen to address the problem. By breaking a complex system into distinct mental and physical entities, we have lost the ability to understand the relationships among the parts. Perhaps our systems are not “broken” but are functioning exactly as designed. Perhaps we have created the systems that inherently create our conflicts.

At issue here is that the social-ecological system that supports us physically, mentally, and emotionally is not simply complicated; rather, it is complex and cannot be meaningfully pulled apart and the parts studied in isolation [9]. Complicated systems are just simple systems with many parts. In simple systems, whether the parts are many or few, interactions among parts are well-defined and predictable, and thus the system as a whole is well-defined and predictable (at least in theory). This does not mean that the system or the problems arising from it are necessarily easy! For example, cars, photocopiers, and spacecraft are complicated systems. Complex systems consist of few or many parts, but the source and essence of complexity arises from the richness, intensity, and character of the interactions among constituent parts. Typically, these interactions lead to non-linear and/or emergent behavior (behavior that cannot be predicted by studying the parts of the system individually). Furthermore, the interactions (as well as the specific connections over which these interactions occur) constantly change, compounding the difficulty of thorough analysis by the formation/dissolution of amplifying/stabilizing feedback loops.

Thesis 4: There is no hierarchy of problems.

We used the sinking ship analogy earlier to suggest that when dealing with systems, there is often no hierarchy of importance of problems. Either something is keeping the system from functioning as we wish, or it is not. In our world today, we have social problems, economic problems, and environmental problems. These are simply the problems that occur in our social-ecological system. One of the more pernicious debates we have engaged in as a society is, “Which is most important?” This discussion makes three fundamental assumptions, all of which are incorrect. First, that problems can be separated this way. Second, that there is a linear cause-and-effect relationship among these issues. And third, that a hierarchy can be established. To show the fallacy of this thinking, take the example of increased anthropogenic carbon dioxide in Earth’s atmosphere. Is it an environmental problem? Yes, and it is a problem that has data that allow us to model it in mathematics classes. It is causing climate instability, habitat destruction, loss of species diversity, ocean acidification, desertification of susceptible habitats, sea level rise, etc., and some of these issues can be studied in a mathematics classroom. Is it an economic problem? Yes. Higher food prices, strain on economic institutions, etc. Is it a social problem? Yes. We are seeing increasing numbers of climate refugees, loss of arable land for food production, and food and water insecurity. Furthermore, the most vulnerable of people, typically the poorest, are disproportionately affected by these changes. Yet typically most of this is not mentioned in a mathematics classroom when looking at increased atmospheric carbon dioxide.

Even with the intertwined nature of the issues associated with anthropogenic carbon dioxide, if there were direct linear cause-and-effect relationships among these issues, it might be possible to make headway by separating the issues into areas. But there are not. Does poverty drive environmental destruction or does environmental destruction drive poverty? Both. Does economic instability drive social instability or does social instability drive economic instability? Both. Does lack of access to quality education drive under-employment and un-employment or is it the reverse? Both. Because the causes and effects go both ways, there can be no strict hierarchy of importance or order to address the issues. Instead, they should be addressed simultaneously — and we should be making these connections when teaching.

Social Justice and Sustainability: The same starting point.

Our discussion to this point thus lays out four fundamental assumptions or starting points for those of us who are considering the problems in the world:

(1) Humans can and must do better than this.

(2) The actions of people today are limiting the choices and options of our children and grandchildren.

(3) The system itself is the problem.

(4) In a complex world, problems cannot be approached on a reductionist one-by-one basis.

These four key statements, originally introduced in [8], might be a starting point for the earnest environmentalist. They might be the starting point for the dedicated social justice activist. They might be the starting point for most of the world’s problems, but they are in fact the fundamental starting point for the young field of sustainability science [7]. The point we wish to emphasize is that social justice, environmentalism, and sustainability are all just different lenses on the same view: How do we work for improvements in human health, ecosystem health, societal health, and economic health? Literally, how do we make sustained improvements in the social-ecological system?


Now that we are thinking in terms of a system, let us look at a few issues from the two perspectives and see how the system might get discussed in a mathematics classroom. Our goal here is not to outline explicit lesson plans or problems, as is done in the many modules in this volume, but to see how we may provide a context for mathematical discussions of three sample topics.

Issue 1: Climate change. Climate change, at first glance, appears to be a purely environmental or sustainability issue. We can measure carbon dioxide levels in the atmosphere, calculate yearly average temperatures, and observe changing ice levels to name a few climate change related issues. From the perspective of a mathematics instructor, there are many ways to engage climate issues in the classroom. There are simple climate models as in Tung’s book Topics in Mathematical Modeling [21], basic curve fitting [16], investigating melting sea ice [17], and distributions of temperature deviations [6], to name a few.

All of this can be done as if people did not exist at all. But when we are thinking of the social-ecological system the issues are much more complex than a “simple” study of a warming planet. It is people, predominantly wealthy, that use the majority of fossil fuels that emit carbon dioxide. However, a warming planet will disproportionately impact poor populations even though they are not the main contributors to carbon dioxide in the atmosphere.

Consider the peoples of the small Alaskan village of Newtok. The villagers of New­tok are often referred to as America’s first climate refugees [27]. Rising temperatures and melting permafrost have led to the erosion of the banks of the Ninglick River to the point that the village has to be relocated before it is under water, and is, in fact, currently being relocated.These villagers are poor and did not contribute meaningfully to climate change, but they are being impacted. Who then pays the cost to relocate the village? Even moving the village is a complex socio-economic problem with the relocation having been halted at least once.

In this example, we set out a path where we got at the social justice issues by starting with the environment. It could certainly go the other way: Start by examining how an increase in the gas tax would impact people, which then might lead to how carbon dioxide emissions might change, and then a discussion on climate. Similarly, we could start the story by examining refugees around the world, which could lead to Newtok as well as other climate refugees. This brings us back to climate change. When we think in terms of systems, there is often no set starting point nor any clear and easy solutions.

In the end, to have projects in a mathematics class that only recognize the measurable environmental changes while ignoring the impact on peoples and the ethical issues involved is to ignore the social-ecological system. At the same time someone more focused on social justice concerns should not ignore the measurable changes to the planet. It is important to keep the focus on the entire social-ecological system.

Issue 2: Income inequality. Income or wealth inequality is a quintessential social justice issue.
There are numerous ways to incorporate this issue into a mathematics course. The topic lends itself nicely to introductory statistics with income and wealth distributions as excellent examples of skewed distributions. There are online resources such as the world top income database [1] and a now classic video on income distribution [18], calculus classes can discuss the Gini coefficient [4] as a measure of resource inequality including income and wealth. Many of these topics have time series associated with investigating changes of inequality over time.

At the same time, it is possible to consider income inequality as part of the larger issues within the framework of the social-ecological system. For example, the debate about hydraulic fracturing and drilling (fracking) in New York State ties this all together nicely.Those in favor of fracking were disproportionately lower on the economic ladder than those opposed to it. The reason can be easily summed up by the notion that it is hard to worry about future generations when you cannot feed yourself today. As part of the framework we have noted that we are already limiting the options of future generations and a substantial piece of that problem is tied to income inequality.

Introducing some form of carbon tax to limit climate change is an equality issue also. Climate refugees now and in the future are disproportionately poor but yet are not the primary carbon emitters that caused the problem. Who should pay for their relocation? A more equal society could more easily spread out the cost of solving many of our ecological problems.

Issue 3: Lead exposure and crime. It is well documented that our judicial system impacts minorities much differently from non-minorities. Issues of race and the judicial system may appear to be a social justice issue but not part of our social-ecological framework. Given the abundance of quantitative data on the subject the issue is easily incorporated into statistics courses as well as other general education mathematics courses. How might this be part of the social-ecological system?
Overall crime rates have been declining for about two decades in the U.S. There are many explanations for this but they typically lack a universal explanation. Nevin has put forth the hypothesis that reduction in environmental lead, primarily from cars but also from paint, roughly two decades before crime started declining is at least part of the explanation [14,15]. Lead is an environmental pollutant with known impacts on human brain development and negative impacts on plant and wildlife populations[26]. Thus, lead is an ecological problem as well as a societal problem. It is a sustainability problem.

When young children are exposed to lead, the negative impacts on brain development increase their likelihood of making poor choices in their late teens and early twenties.Hence,there is a posited connection between lead exposure and crime. Nevin’s work goes further and points out that inner city African-American populations were disproportionately impacted by environmental lead. The story on the lead, crime, and race connection is ongoing, but it provides an example of how an environmental toxin, lead, may have impacted communities two decades later while at the same time having a disproportionate impact on inner city residents. Given underfunded lead remediation efforts, income inequality is part of this story too, but recent gentrification in older neighborhoods has led to increases in lead exposure at all income levels. See [4] for more.

The Nevin data can be a resource for regression analysis, and is the topic of one of the modules in this book. This example is just one of many environmental justice issues.Van Jones puts it succinctly in a 2008 interview when asked what stake people of color have in the environmental movement. He responded, “A big one. It’s the people of color who are disproportionately affected by bad food, bad air, and bad water. People of color are also disproportionately unable to escape the negative consequences of global warming. Look at Hurricane Katrina. People of color need equal protection from the worst environmental disasters and equal access to the best environmental technologies” [10]. In many ways, Van Jones’ ideas apply to not just people of color but to the economically disadvantaged.


What is the difference between social justice and sustainability? Nothing. Nothing, that is, if we remember that humans live in a coupled complex social-ecological system. It is the system itself that allows us to exist on this earth. It is changes in the system itself that social justice activists and sustainability advocates are promoting. And we are all working toward a common goal: improved physical, psychological, and emotional well ­being for all.


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