Professor, Princeton University
UTP IAC Member
Environmental issues are ubiquitous. Climate change, air pollution, loss of biodiversity, food security, ecosystem degradation, and infectious disease are some of the environmental topics routinely discussed in both academic literature and the popular press. Given the importance of these issues, educational institutions need to consider how their students should be educated so that they understand, and ultimately contribute meaningfully to, practical and sustainable solutions to these environmental problems. No matter what discipline a student chooses as their major focus area, basic literacy in critical environmental topics should be part of their education. This literacy might come from one or more targeted courses, a series of shorter modules, or some other means; the specifics need to be determined by each institution. But environmental literacy should be required in every modern twenty-first century educational program.
Specific examples related to different topics are presented below to illustrate potential modules for environmental literacy education. My own preference is to focus on numbers and concepts – I believe every student needs to know a few important numbers as well as the related context for those numbers; I also believe there are a few concepts that are critical to environmental problems and these concepts need to be taught.
Example #1 – Climate Change Numbers (and their context)
Consider the most discussed environmental topic: climate change. What are the most basic facts that all students should know? I like to start with a simple set of three numbers, with the context for each number included in their description. The three numbers are: 420, 10, and 2. The first, 420, is the approximate current concentration of CO2 in the atmosphere, in units of parts per million by volume (ppmv). The context associated with this number includes the following: (1) CO2 is an important greenhouse gas; (2) the atmospheric concentration of CO2 was around 280 ppmv at the beginning of the industrial revolution; (3) the rise in CO2 concentration has been driven by emissions associated with human activities, mostly involving burning of fossil fuels (coal, oil, gas), and (4) while a few hundred ppmv seems small, it can have (and is having) a major impact on Earth’s climate. The atmospheric concentration has been measured directly since the 1950’s, and the graph of these measured values as a function of time is usually called the Keeling Curve, named after the person who initiated the measurements at an observatory in Hawaii. For earlier times, gas bubbles trapped in old ice provide direct evidence of the atmospheric concentrations over the past centuries and millennia. Among other things, the history of CO2 concentrations shows that the concentration was stable over the last 10,000 years, up until the industrial revolution. Deeper into history, CO2 concentrations are correlated with ice ages, with glacial/interglacial cycles of around 100,000 years occurring over the last million years. Importantly, the maximum CO2 concentration over the last million years is about 300 ppmv. This means that human activities have driven atmospheric concentrations well beyond anything seen in the history of the human species. These numbers can be seen in the graphs presented in Figure 1.
(a)
(b)
(c)
FIGURE 1: (a) The Keeling Curve, showing measured atmospheric concentration of CO2 as a function of time beginning in 1958. (b) Atmospheric concentration of CO2 over the last 10,000 years; (c) Atmospheric concentration of CO2 over the last 800,000 years. Figures from
https://keelingcurve.ucsd.edu (Figures retrieved 20 June 2023).
The second number, 10, is the current rate of anthropogenic CO2 emissions in units of gigatonnes of carbon per year (1 gigatonne = 1 Gt = 109 tonnes = 1015 grams). It is important to be clear about units, because one CO2 molecule has molecular weight of 44, with only 12 of that coming from the carbon. So, the emissions in units of Gt CO2/yr is 10 Gt C/yr * (44 Gt CO2/12 Gt C) = 37 Gt CO2/yr. I prefer using units of mass of carbon, instead of mass of CO2, because the number 10 is easy to remember, and when looking at the global carbon cycle it is the carbon mass that is tracked and balanced. However, mass of CO¬2 is often used as a reporting unit, so everyone needs to pay careful attention to units when looking at “carbon emissions”. For context, it is helpful to know that in the middle of the 20th century, emissions from fossil fuel combustion were around 2 Gt C/yr (see Figure 2); that on a national basis China is currently the largest emitter (11.4 GtC/yr) followed by the United States (5.1 Gt C/yr), India (2.9 GtC/yr), and the European Union (2.8 Gt C/yr); and on a per-capita basis, US emissions are around twice as high as China’s. The United States also has the highest cumulative emissions since the industrial revolution, followed by the EU and China. While there have been various international agreements, with associated pledges to reduce emissions, overall global emissions of CO2 continue to rise and, to date, nations have made inadequate efforts to reduce emissions despite pledges to the contrary.
FIGURE 2: CO2 emissions as a function of time, showing emissions from fossil fuel combustion as well as land use change. Note the dominance of fossil fuels over the last sixty years. Current CO2 emissions from fossil fuel combustion is around 37 Gt CO2/yr = 10 Gt C/yr. Figure from Global Carbon Project [https://globalcarbonproject.org]. Figure retrieved 20 June 2023.
The third number, 2, represents a long-standing target for the global average temperature rise, in degrees Celsius, by the end of this century. This number came from a general sense that temperature increases beyond 2 ⁰C represent a dangerous level of climate change. Additional contextual information includes the fact that the global average is calculated for the entire globe, meaning both ocean and land. Temperature increases at the earth surface are higher over land than over the oceans, so land-based locations will experience temperature increases higher than the global average value (see Figure 3). In addition, temperature increases in the high latitudes have been observed to be much higher than the global average. For example, the arctic region has been warming about 4 times faster over the last 25 years than the global average. Since 2016, when the so-called Paris Agreements identified a temperature increase of 1.5 ⁰C as an aspiration goal, there has been significant discussion about 1.5 degrees as the new target. Given that the current average global increase now exceeds 1.2 degrees, and emissions continue to rise, keeping the global average temperature increase below 1.5 degrees is essentially impossible.
Figure 3: Average temperature increases as a function of time over land and the oceans, relative to averages taken over the fifty-year period between 1850 and 1900. Figure from Berkeley Earth, Global Temperature Report for 2021 (URL:
https://berkeleyearth.org/global-temperature-report-for-2021). Figure retrieved 27 June 2023.
Once these numbers are understood, on their own and contextually, then a series of follow-up topics can be considered. These might include: Methane and other greenhouse gases; Feedbacks in the climate system; Impacts of climate change on water resources and the water cycle; The IPCC and its reports; Options for carbon emissions pricing and other policy instruments; and Creative ways to communicate the science of climate change. Climate change impacts all aspects of life, it is discussed every day in the popular press, and every student must have basic literacy in the subject.
Example #2: Two important
concepts: Sustainability and Environmental Economics
Sustainability: Everyone talks about sustainability as though we all know what it means. While each of us probably has some general idea about the concept, I find that very few people can give a concise and coherent definition of the term. While a wide range of definitions exists, most are vague and have little or no quantitative basis. I prefer to define sustainability using the Ecological Footprint concept. The idea of the ecological footprint, which was proposed 30 years ago by William Rees and Mathis Wackernagel, recognizes that waste products from one set of organisms are often used by other organisms in continuous cycles, sometimes referred to as biogeochemical cycles. Within this context, Earth can be seen as having capacity to assimilate and transform waste products from human activities. Prior to large-scale human disturbance, the Earth’s biogeochemical cycles were in balance, functioning in a dynamic, stable state. Human disturbances have pushed the Earth system out of balance in almost every way. The Ecological Footprint attempts to quantify this imbalance using a consistent unit of measure - land area - and includes many of the major element cycles. The current footprint analysis shows that at least 1.8 times the land area on earth is needed to assimilate the waste products from human activities, meaning we are living unsustainably. While not perfect, I find the ecological footprint concept to be conceptually coherent and quantitatively consistent. It is also easy to explain, and online materials are readily available. A simple primer on the Ecological Footprint concept serves all students well and allows understanding of the Earth system and how humans drive multiple imbalances, and ultimately how this can be used to understand the concept of sustainability. This can also be coupled with the more local analysis tool of life-cycle assessment to provide a more comprehensive picture of the basic concepts of sustainability.
Environmental Economics: Environmental problems cannot be solved effectively without a basic understanding of environmental economics. The field of environmental economics recognizes that the usual theories of economics do not apply to most environmental problems. This is because the “costs” associated with harming the environment are usually not felt by the person or industry causing the harm. For example, discharging waste into the air or water incurs no cost to the polluter, despite the harm caused to those downstream who are forced to deal with degraded air or water quality. The field of Environmental Economics is focused on ways to internalize the harm caused by a polluter through creation of a cost mechanism. This almost always requires a public policy component wherein governments create economic structures that serve to control the environmental harm, either through direct emissions regulation or through creation of a market where emissions allowances are bought and sold. The main point is that government intervention is required to make this work, and public policies are needed to properly value environmental public resources like air and water because these common resources usually do not have private ownership. Environmental problems will not be solved without government involvement, a point that needs to be understood by every student. Environmental economics explains why government action is required and how policies can lead to various kinds of optimal solutions.
Final Comments
While an in-depth focus area on the environment exists at most institutions - for example, a major or minor concentration in Environmental Sciences - there is usually no university-wide requirement that all students must have some education in environmental topics. Such requirements typically exist for other subjects; for example, at most universities all students must satisfy a set of general education requirements in subject areas like Historical Analysis, Social Analysis, Literature and the Arts, and Science and Engineering. These general education requirements can almost always be satisfied without ever taking a course related to the environment. My argument here is that, given the ubiquity of environmental issues in every-day life, their importance to the welfare of our species and all other life on Earth, and the enormous societal impacts including our future economic well-being, every institution of higher learning should have an educational requirement in Environmental Literacy. The components of this environmental literacy requirement, and the modes of teaching associated with them, will vary from one institution to another. But it seems well past time for every graduating student to have basic competency in the most important environmental topics. Major public policy decisions need to be taken around critical issues like climate change and biodiversity, and an informed and environmentally literate citizenry is essential to make good decisions. Institutions of higher learning must play their part - the future of our planet depends on it.
