# Footprinting in a course on energy

Seth A. Major  Department of Physics
Hamilton College
Clinton NY 13323 USA<EMAIL_ADDRESS>
(Date: 24 July 2023)

###### Abstract.

Footprints provide a way to estimate the relative impact of processes and
products on the global climate. Including footprint analysis in a course on
energy simultaneously provides students with an understanding of this tool and
a quantitative guide to approaches that address climate change. College-level
classroom activities for (primarily) process-based life cycle carbon
footprinting are discussed.

##  1\. Introduction

Whether teaching upper-level statistical mechanics or an introductory course
on energy, I find that students are keen to learn ways we can address climate
change. Footprinting is one quantitative method to guide approaches to
reducing emission of anthropogenic greenhouse gases. In this article I share a
‘nugget’, as described in the prompt for the special collections on the
physics of the environment, sustainability, and climate change: a brief
description of classroom activities on footprinting to which the students
responded favorably.

In the next section I sketch the course settings in which I have implemented
footprinting activities, including discussion of the necessary background
required for the activities. While the discussion focuses on footprinting in a
course on energy, these activities may be included in courses statistical
physics courses. In section 3 I briefly introduce carbon and ecological
footprints. The classroom footprinting activities are described in section 4.
Finally, I conclude with some discussion and student feedback to the
activities in section 5.

##  2\. Teaching contexts

Elements of footprinting can be most easily incorporated into college physics
courses on energy, but they can also be incorporated into traditional upper-
level statistical physics courses. The classroom activities described in the
next section were developed for “Humanity’s Global Impact and the Adirondacks”
(Coleg-370). This course was part of the Hamilton Adirondack Program in 2016
and included an approximately two-week development of footprint analysis. See
Appendix A to more on the program and course. Sample example questions are
given in Appendix B.

The goals of Coleg-370 are:

  1. (1)

To understand a detailed “back of the envelope” calculation of global warming
due to CO2 emissions from fossil fuels.

  2. (2)

To discover insights of the system-wide thinking of thermodynamics.

  3. (3)

To become more number savvy.

  4. (4)

To be able to determine the reduction of CO2 emissions due to specific actions
or policies.

  5. (5)

To practice using those tools by applying them to local contexts.

We use footprinting to understand the flow of carbon in producing items or
running activities. Applying the quantitative and spreadsheet skills developed
earlier in the course, students address what factors might be important in
carbon production and find gaps in our understanding and data. They see how
footprints can be used to help direct changes to address climate change.

The course covers necessary background for the footprinting activities
including, (i) the physics of energy, taught in an essentially traditional
approach, (ii) quantitative skills in building spreadsheets and in
incorporating uncertainties taught in laboratory exercises, and (iii) a
quantitative “back of the envelope” calculation of climate change that
includes the carbon production in burning fossil fuels and an estimation of
the global warming due to this additional CO2. The approach to the calculation
is similar to Tom Murphy’s “Do the Math” blog [1]).111I also include this
curricular element in my junior-level statistical physics courses as an
application of blackbody radiation. Before concluding the semester with the
footprinting, we discuss energy systems.222Valuable for this portion resources
include MacKay [13] (excellent and free, but focused on the UK) and Murphy
[11] In upper-level statistical mechanics courses students have much of this
background already so I only include (iii) in this context.

To support the carbon accounting, it is helpful to find the carbon intensity
of combustion and motivate the unit CO2e. In the calculation of carbon
produced in burning fossil fuels, one finds that the carbon intensity of
fossil fuels is about 3g CO2/g (grams of CO2 emitted per gram of combusted
fuel) across all fossil fuels. In the course we investigate the relative
radiative forcing of greenhouse gases by comparing absorption around 10
$\mu$m, which is the peak wavelength of a blackbody spectrum at about $T=288$
K. This gives a metric of the relative radiative forcing among greenhouse
gases. Because the radiative forcing and the lifetimes of these gases in the
atmosphere vary significantly, it is helpful to normalize the impacts. We,
thus, come to the standard carbon footprint unit of grams of CO2 equivalent or
CO2e: the amount of CO2 that would have the equivalent global climate impact
over a hundred year period.333The radiative forcing of key greenhouse gases is
both highly variable and complex (our understanding is evolving, see [20]).
For instance, by integrating absorption spectra in the infrared we see that
methane is about 60 times more potent than CO2. But methane chemically breaks
down faster in the atmosphere. Over the hundred year period it is about 28
times more potent than CO2. For more see the IPCC report [14], Chapter 9 in
[11], and [2].

##  3\. Footprints

Humanity’s impact on the world is both broad and fine-grained. For example, it
has a significant affect on biodiversity, availability of fresh water, soils,
and climate, only some of which may be directly addressed by changes guided by
footprinting. When addressing climate change, it is natural to study the
carbon footprints of products and processes to identify drivers in greenhouse
gas emission. Other accounting methods, such as the ecological footprint (EF),
widen the focus to include water and land areas to support activities. While
both carbon and ecological footprinting techniques are still under
development, the accounting nonetheless provides a useful quantitative guide
to determine which avenues might reduce greenhouse gas emissions and, in the
case of EF, our broader impacts on the environment. Other methods of analysis
and modeling are necessary to guide choices in addressing other areas of our
impact such as biodiversity loss. In this section carbon and ecological
footprints are defined and sources are discussed. Activities based primarily
on the carbon footprint metric are described in the next section.

Carbon footprints are usually based on a process-based life cycle assessment,
an input-output analysis, or, a combination of both.444See the “Where do the
numbers come from?” chapter in [2]. The process-based assessment accounts for
the carbon and other greenhouse gases released in producing, using, and
disposing of a product or completing an activity. It is a bottom-up approach,
building the total footprint from footprints of sub-processes. An advantage of
this approach is that it is specific to the item. The carbon footprints of
sub-processes are modeled so the origin of the carbon in the model is clear.
But process-based assessment is subject to truncation error when sub-processes
are inadvertently left out. For example, a process-based carbon footprint of a
smartphone could include emissions from manufacturing and transporting but
might omit emissions due to mining the required raw materials.

The top-down approach of the input-output model555At its heart the work is
nifty bit of linear algebra that tracks the outputs of one sector of industry
with the inputs of other sectors. The method was created by Wassily Leontief,
for which he received the Nobel Prize in economics in 1973. starts with the
whole economy and its carbon output. As such, the input-output approach isn’t
subject to the truncation ‘leaks’ in the process-based approach. However,
input-output analysis does not have the specificity of process-based
assessment. In part because the input-output is based on linear algebra and
requires large data sets, I have not used this method in classes other than to
refer its results during discussions of more complex processes such as the
carbon footprint of iPhone production. As I describe in the next section,
there are enough subtleties in process based assessment that it make sense to
focus student work on the process-based approach in an introductory setting.

One engaging source on carbon footprinting is Berners-Lee’s The Carbon
Footprint of Everything [2]. Now in its second edition - it was previously
titled How Bad are Bananas? \- it makes for surprisingly fun reading. The
notes in the back of the book are a goldmine for those wishing to look into
footprinting methods and literature. One of the students in Coleg-370 wrote,
“The best way [to] overcome [the] barrier to action would be to have everyone
read Berners-Lee.”

The ecological footprint (EF), developed by Wackernagel and Rees [3], recasts
the environmental impacts of our activities (and populations) in terms of area
of land and ocean required to generate the resources and to absorb the waste
they generate. The EF unit is numbers of earths, that is the number of earths
to sustainably maintain a way of life. This may be stated as “If everyone on
earth adopted the same lifestyle as those living in country $X$ then this
would require $Y$ earths.” (Typically, $Y>1$.) Students noted the appeal of
this choice of expressing the result, “… for me, footprints expressed in
earths are the most meaningful, because it is a unit we can all visualize,” as
one student noted.

The EF is extensively developed by the Global Footprint Network (GFN) [4].
Useful sources include the online calculator [6] and curricular materials
available through EUSTEP (Enhancing Universities’ Sustainability Teaching and
Practice through Ecological Footprint), a partnership between the GFN and four
universities [7].

Although the EF has an intuitive unit, the computation of the EF is often
country-based and, particularly with online calculators, can seem like a black
box. For instance, I assign students to use this calculator for their own
footprints in two different countries. They often find that with the same
personal inputs, the resulting ecological footprints are radically different,
which initially puzzles students. Even after they understand society’s role in
the variation of ecological footprint, it is not clear which policy choices
lead to the significant differences.

##  4\. Footprinting in the classroom

Students are ready to footprint when they have background in energy and the
‘back of the envelope’ calculation of climate change and have some experience
working with data, uncertainty, and spreadsheets. In this section I describe
the classroom activity which includes warmup footprint calculations in the
small-class setting of Coleg-370. Afterwards I comment on changes that I have
made to incorporate simple footprinting into a larger class setting in a
statistical physics course. These activities are not prescriptive and may be
adapted to different courses and settings.

The footprint activity starts with guided discussion on an item’s footprint
that is (at least initially) uncomplicated. For instance, I hold up a cup of
tea and ask, “What is the carbon footprint of a mug of hot water?”666See [5]
for an approach using an electric kettle to explore energy use and life cycle
assessment. In a small class setting a whiteboard or a blackboard work well to
keep track of the scope and to perform initial calculations. Although I don’t
explicitly say this at the beginning, the initial round of discussion and
calculation is really about the choices involved in defining the footprint.

I let students take a lead on the initial quantitative discussion, with my
role being more of a scribe and an occasional guide. My students tend to
gravitate to a simple thermodynamical “$Q=mc\Delta T$” computation of the
energy required to boil the water. For instance, we might calculate the carbon
produced when burning natural gas to raise the temperature of tap water to
boiling. We find a preliminary carbon footprint in terms of grams of CO2 using
the carbon intensity we found during the “back of the envelope” climate change
calculation.

Even during the initial discussion, students often find the complexities
involved in even the most simple computations, but, if they do not, I push on
the assumptions. Suppose we find an unrealistic footprint based on heating on
a gas burner (about 4 g CO2). I point out the assumption - often not
explicitly stated - that all the heat of combustion was transferred to the
water. I prompt students to re-consider, asking, “If this was the actual
footprint wouldn’t we be comfortable holding our hand above the pan while the
water is heating up?” This observation returns us to another round of
quantitative discussion, defining the problem with more care, and refining the
computation. It is also useful at this stage to look at more than one method
of heating. Depending on whether there is equipment available - in Coleg-370
the kitchen was in an adjacent room - the next stage of taking data can be
completed during the first class activity on footprinting.

Equipped with timers, information on the stoves, and electrical consumption
meters like ‘Kill-A-Watt’ meters they boil water to refine their initial
calculations. They time how long it takes to actually boil a cup of water on a
burner of known power. During these measurements I encourage students to
observe and record what they actually do. For example when boiling water on a
stove one frequently uses a larger volume than one cup while when heating
water for tea in a microwave one often heats just the water we intend to
drink.777Thanks to Beth Parks for this observation. For heating with an
electric kettle, we use the local electrical mix on the grid from energy
generation portion of the course.

At the end of these preliminary footprints, we return to the definition of the
footprints and the manner in which we communicate the results with their
limitations. Now with students more aware of the processes that may be
included, we discuss whether to include the footprint of potable water and
waste systems. This reflection may lead us to new definitions, calculations,
and results. For example, we might choose to find the carbon footprint of the
energy required to heat water with natural gas, about 14 g CO2, and to neglect
the footprint of the infrastructure required to deliver the potable water.
Likewise heating a cup of water using an electrical kettle, powered by the
local grid, has a footprint of about 19 g CO2e.888The change in units is due
to the use of the electrical mix from the grid but the results may be directly
compared due to the choice to normalize the impact using CO2.

The process of reflecting on the definition helps students see that
variability in the scope of footprints. In most of these questions the goal is
not only the “correct answer”, but rather the consciousness of the decisions
that define our results. This is a key element of the approach to footprinting
advocated here. Like some undergraduate physics laboratories the activity is a
cyclical process of defining, calculating and measuring, reflecting on the
results. The activity highlights the choices and limits involved in process-
based carbon footprints. In addition, by explicitly working through
computations students have full access to what is done in these computations,
unlike the results of an online footprint calculator.

It is possible to adapt this activity to other class settings, as I have done
in a statistical physics course. In larger class settings, the initial
activity can be done with group work using large, shared whiteboards for
tables. (The physics department has cut $40\times 90$ cm2 whiteboards for such
discussions.) Depending on the size of the class, this may require TA’s to
help guide the discussion. In my classes at least some students have access to
kitchens. This measurement portion is completed as homework in ‘dorm-kitchen
labs’ and discussed in the next class meeting. As I have adapted the activity
in a more conventional instructional setting, the activity is a discussion
taking less than one class period followed by homework activities and an in-
class discussion during which the final versions are found. In statistical
physics courses, which lack the coverage of energy systems included in
Coleg-370, the renewable mix on the local grid and how much energy is lost in
delivery are briefly discussed in class.

The first full footprint of a product starts with an item that (at least some)
students know well so they can apply their understanding of the processes
involved. A main goal for this activity is a more complex footprint
calculation. We explore the scope of what one might consider. We take more
care to note where numerical inputs are ‘squishy’, i.e. have high relative
uncertainty, when different sources offer significantly different results,
and/or when the data is from a simple internet search. In addition to the
blackboard it is very helpful to have cloud-shared documents and spreadsheets
such as those hosted on DropBox, Google Drive, or OneDrive. This way students
can quickly share tips, work, and sources during the discussion. Additionally,
it is helpful to have access to a high quality published study with plenty of
direct measurements, allowing one to dig into details (such as [16] used in
the example below).

For example in the HAP everyone made food and participated in the Essex Farm
CSA food pickup. Some students interned on farms cultivating vegetables and
were familiar with plastic row covers, harvesting, refrigeration, tractor use
(and parts required for repairs), and irrigation. So a natural choice was a
farm product they knew well. I chose a computation of the footprint of
lettuce. This first footprinting activity started with a discussion of
contributing processes, dividing them into categories of “to the farm gate”,
“to the store door”, and ‘to the dinner table”. While we eventually studied
all of these categories, we started with the “to the farm gate” footprint. A
spreadsheet with the computation is available as supplementary material [17].

To manage the problem, and to clearly mark what is included in the footprint,
it is essential to break down the product or process. In the initial
discussion we used a blackboard to record the breakdown of individual
processes involved asking, “How is the product made? Where to the parts or
inputs come from? What do we include in the footprint?” The resulting
breakdown allows us to list smaller, manageable steps, to note needed data,
and to define the calculation. The process is highly customized to the product
or process. In fact this is a strength of the process based assessment.

In the case of lettuce we asked, “Was the lettuce grown outside or in a green
house? Was the crop conventionally grown or organically grown? What is the
tractor use? Is fertilizer used? Was there post harvest cooling? What sort of
packaging, if any, was used? How was the produce transported? Do we need to
include warehouse infrastructure?” The guides for the discussion were both the
students’ experience and the published study [16]. We discussed ways to
express the result. For instance, what is the best unit to describe the
footprint, an acre, pound, calorie, head, or serving of lettuce? The students
chose a head since it represents both a common unit for the farm and the
consumer.

Since 80% of lettuce consumed is conventionally grown, in class we decided to
find the carbon footprint of a conventionally grown head of lettuce as it
leaves the farm. (Later, we compared the result to the footprint of lettuce
produced locally.) Defining this footprint and determining which data we
needed was conducted in a class discussion using both the blackboard and the
shared spreadsheet. During discussion students started to fill in the
footprints for individual processes such as tilling, working from knowledge of
what is required, adapting the results in the published study [16], and
checking basic inputs such as the rate of diesel consumption.

Next we extended the result to the carbon footprint of a conventionally grown
head of lettuce as arrives prepared on the dinner table. Developing these
footprints allowed us to find significant contributions to the carbon
emissions of growing and delivering lettuce. Key possible contributions
included air freight, refrigerated transport, and greenhouse heating. The
computations were done in teams focused on different individual processes
using the cloud-shared spreadsheet. Work was done both in class and in
homework. We included comments and citations of the sources in the spreadsheet
so we could both check our work and use the spreadsheet as a reference for
future footprints.

While the focus of Coleg-370 was not on society and policy, HAP did have such
a focus. Reflecting on these results at the end of the fall harvest led to far
ranging conversations. Discussions included our choice of diet and an apparent
rural-urban split in the expectation of readily available lettuce year round
versus other produce such as cabbage or pickled vegetables. Given the fossil-
fuel-light farming methods, including horses (“shaddowfax” in MacKay’s
parlance) used at Essex Farm we realized that the literature did not contain
data on the carbon production and sequestration on diversified farms such as
Essex Farm, which suggested new research collecting the data.

Other early footprinting activities might include on-campus initiatives such
as end-of-year furniture swaps (comparing furnishing rooms with new sofas,
etc. versus used furnishings from the swap), student-run coops, real-time
energy monitoring systems, and on-campus composting. Ideally, these are
student-driven or student-inclusive initiatives so that the students have
knowledge and ownership of the systems and processes. Once students have found
several footprints, and have access to a small library of examples, working
independently becomes possible. Students then have some basis to evaluate
whether their footprints make sense.

In addition to footprints described in assigned reading in Berners-Lee [2] we
also studied carbon footprint analyses of iPhones (leaning heavily on Apple’s
version, e.g. [18], and Berners-Lee’s critique [2]), solar panels, the 2016
Olympic Games in Rio [21]. We created footprints for other locally produced
goods, Hamilton College, and the Hamilton Adirondack Program (see Appendix C)
in more detail. For the HAP assessment we worked as a team, dividing the tasks
of assessing housing, food, the guest speaker program, vehicle use, and
outdoor activity gear. By this point in the semester it was not surprising to
see that travel was the main contributor of carbon in the HAP footprint
(Appendix C). This led to suggestions on how to change the program structure
to lower the carbon footprint. At the end of the footprint portion of the
course, students were able to independently complete process-based carbon
footprint calculations. Every student completed a new footprint as part of the
final exam.

Faculty preparation for the footprint activity includes running a few of these
footprint analyses in advance. It is useful to work from published work with
plenty of direct measurements and to keep open to new possibilities that
students raise. One of the pleasures of teaching this subject is learning from
student insights.

##  5\. Discussion

Saadia Zahidi of the World Economic Forum is quoted as saying, “What you can
measure, you can address” [19]. Footprinting offers a metric to prioritize
solutions that address climate change. The activity also serves as a bridge
between online ‘your footprint’ calculators and summaries such as in [2], and
full-blown, careful studies, making the process more transparent and
instilling an understanding of its power and limitations. The footprinting
activity requires background in energy and the basis of climate change, as
well as a facility with spreadsheets. For a first footprint, it was helpful to
choose an item that the students knew well, that wasn’t too complicated, and
that had at least one solid study to draw from. In Coleg-370 over the course
of two weeks students developed a handful of process-based life cycle
assessment carbon footprints of products and activities. In upper-level
statistical mechanics courses, simple carbon footprints can be included as in-
class example and in homework, although this omits the significant lessons on
scope and definition that a longer unit includes.

Students in both these settings responded enthusiastically to the inclusion of
discussion of climate change and, in the case of Coleg-370, to the “What can
we do about it?” unit based on footprints. Perhaps part of the reason is due
to the surprises: Purchased out of season air-freighted fruit? You have bought
a “big foot”, a footprint many times larger than similar, locally produced
food.999It is rarely simple to determine whether a product traveled by air.
However, stores often include country of origin. Perishable foods that travel
far are often air-freighted. For example, fresh blueberries from Peru
purchased in the Adirondacks in December will carry a large foorprint due to
air travel. Considering a change in diet? A vegan diet can have as big a
carbon footprint as a meat-based diet, if the food travels by air. Computing
the impact through footprints offers a guide to change, whether it be national
transportation policy or sealing leaks in houses. The footprinting activity
offered students a quantitative guide to changes to address climate change.
Some lifestyle changes such as night setback temperatures or different methods
to cook pasta were easy to implement. We can draw from more comprehensive
plans for greenhouse gas reduction (see, for instance, [22]) for potential
larger scale changes.

In Coleg-370 assessment was through written feedback, and focused on the
course goals (4) and (5). The students welcomed the footprinting work as a
guide to what might be addressed to reduce carbon emission. For example, in
reflecting on the footprinting activity one student wrote, “I know that
learning how much a footprint flying, driving, and heating have has totally
changed my perspective. I think having footprint numbers on things like
boarding passes, gas pumps, and heating bills could really help to make people
rethink their usage. … this information needs to be part of every day to day
activity…” Implementing footprinting activities in physics courses creates
opportunities for such a change in perspective.

Acknowledgements Many thanks to the students in the Hamilton Adirondack
Program, Janelle Schwartz, and Hamilton College for support. Thanks also to
the anonymous reviewers whose extensive comments helped to shape the article.

##  Appendix A Coleg-370 Course detail

In 2016 I was fortunate to teach in the Hamilton Adirondack Program (HAP).
This innovative program founded by Janelle Schwartz blended coursework in the
Adirondack park with a deep engagement with the environment and the local
community. The HAP offered students a wide breadth of experiences from
academics focused on both global concerns and the local community to food
production and preparation to working in the area through internships.

The idea was to place global thinking on a quantitative foundation and then
apply this thinking to solutions on a local level. To create the syllabus for
the course I worked backwards from a ‘back of the envelope’ calculation of
climate change and footprinting. This climate change calculation is similar to
what is done in Chapter 9 of [11] and the blog [1], both by Murphy. In
preparation of this article I updated the teaching resources. Asking, “What
background is required to understand the calculation?” and “What skills are
required for the footprinting?” pointed toward material content including the
physics of energy and light and basic chemistry. But the questions also
pointed to necessary background in spreadsheets, heinous unit conversions, and
simple quantitative analysis. I included earlier activities to introduce and
practice these skills. Laboratories were tailored to the site and integrated
into the weekly assignments. In addition to energy labs we carefully modeled
the heat flow in residential structures including blower door testing on the
campus structures. In another (and favorite) lab, students built their own
‘homes’, small structures of their own design and construction. The students
tested the heat loss of their structures using electrical resistive heat and
temperature loggers.

In the first part of the course I followed the ‘force-work-energy’ path
towards understanding energy, essentially following standard physics texts.
Although I followed a philosophy of ‘choose your favorite source’, I assigned
reading by topic in Bloomfield’s “How Things Work” [8] and the algebra-based
Open Stax College Physics [9]. Additional useful texts include Muller’s “…for
Future Presidents” series e.g. [10], Murphy’s Energy and Human Ambitions on a
Finite Planet [11], and Wolfson’s Energy, Environment, and Climate [12]. The
physics background finished with the basics of thermodynamics with it’s
benefit of system-wide macroscopic thinking.

At this stage the students’ work was a mix of qualitative, quantitative, and
working-with-numbers questions (significant figures, basic uncertainty,
agreement, unit conversion). They also built skills working with spreadsheets.
Example questions are in Appendix B. The tailored approach laid the foundation
for footprinting. We studied sources of power, locally, nationally and
globally, electrical grids, electrical energy mix. Although focused on the UK,
MacKay’s Sustainable Energy without the Hot Air [13] is an excellent source
for this material. Murphy’s book offers a most recent presentation more
focused on North America [11]. The course also included a field trip to visit
to a local small-scale hydropower plant and guest speakers.

Although some students in Coleg-370 had extensive undergraduate exposure to
physics, most of the students said that they would not have taken a physics
course on the Hamilton College main campus. It was rewarding to observe their
success and valuable for all of us to hear different perspectives, some of
which were quite different than I usually have in the physics classroom.
Grading was based on weekly homework questions, computations and short essays,
into which lab writeup incorporated, a midterm, and a final.

##  Appendix B Example questions

This is a sampling of questions101010These questions are from 2016. from the
homework, quizzes, and labs.

  * •

Do you do work while kneading bread? Explain your answer. [Students had just
started to make bread for the community.]

  * •

Explain why we often build structures with steeper roofs in the mountains than
in the lowlands far from snowfall.

  * •

Water descends in Gulf Brook from the Mountain House to the Ausable River in
Keene. What is the maximum electrical energy that the water could generate in
a day? Assume a flow of 911 kg per day. Hint: You need one more bit of
information which is available on the topo map. Compare this to the electrical
energy consumed in one day on site.

  * •

By now you have done a lot of reading and calculating on hydro power. What
role can hydro power play in the Adirondack region electrical energy mix? Draw
from our conversations with Matt Foley [owner of small scale hyrdo facility]
in Westport, the EPA feasibility study, the previous problem, and your
reading. Make sure that, in MacKay’s words, your solution “adds up”.

  * •

Find the carbon and ecological footprints of (a) 1 pint of blueberries (375 g)
flown to Newark, NY from Lima, Peru and trucked to the local Hannaford’s. You
may want to focus on the major contributing factors; (b) 1 pint of raspberries
grown at Essex Farm [the program’s CSA]; and (c) 1 pint of Essex Farm
raspberries frozen for 3 months - this is to mimic the out of season nature of
(a). Comment on the results. For yields use MOFGA’s estimates: “… typical
yields are 4,000 to 5,000 pounds [per acre].”

  * •

Jenkins has a sustainable energy solution for the Adirondack Park [15].
Summarize the solution and compare it to the scenarios in MacKay. Why are they
so different? What are some advantages and disadvantages of Jenkins’ solution?
(Does the park ‘belong’ to people living in it? To NY state? To all? Are there
benefits to such local energy solutions?)

  * •

Congratulations! You have been appointed to the Hamilton College’s ‘Blue Sky’
Committee. (This body actually existed, although the official title was the
“Imagining Hamilton Committee”.) As the climate expert on the committee, you
are tasked with developing a plan to accelerate Hamilton College’s Climate
Plan so that the college is climate neutral by 2030.

    1. a.

Estimate the current carbon footprint of Hamilton College. For data, use
Berners-Lee and Hamilton College’s FY 2016 primary energy, $2.40\times 10^{6}$
kWh of electricity and $1.14\times 10^{6}$ therms of natural gas. Do not
include student travel to and from the campus. Develop a spreadsheet for
Hamilton College’s total carbon footprint.

    2. b.

Use MacKay, Jenkins, and Berners-Lee to map out a climate neutral solution.
Include the possible benefit of the forest on the 1280 acre campus, about 800
of which is forested. At this stage do not worry about financial constraints.

    3. c.

Now discuss the feasibility of your plan.

    4. d.

Submit an electronic version of your spreadsheet.

  * •

What does Berners-Lee’s input-output model give for a minimum emission for
spending $1? Ponder this for awhile then give the argument for intentionally
moderating one’s consumption, i.e. spending those dollars.

  * •

Re-run the numbers for a recently installed 3.92 kW system that cost $4100
(installed, state and federal incentives included). Please find the expected
annual energy savings, payback period, the return on investment, ‘financial
impact of solar panels’, and the CO2 payback period. Assume a cost of
electricity of $0.14/kWh, and the upstate electrical mix of 51, 27, 16, 4, 2
percent for gas, nuclear, hydro, other renewables, and coal, respectively
(www.eia.gov for New York in July). Comment on this system and the example
Berners-Lee uses.

  * •

The director of Physical Plant sends out an annual ‘Building Heating’ email -
perhaps you have seen it - writing, “make sure windows are closed in the
cooler evening hours.” Still many windows are open around campus during cold
weather. To increase participation, what would you add to this email on how
windows operate? Many of us have a tendency - I think - to view this email as
a distraction. How might the director circumvent this problem?

##  Appendix C Hamilton College’s Adirondack Program Footprint

Program Footprint: One of the themes of the course was to answer “What can we
do about climate change?” As part of the focus on the local, we studied the
Hamilton Adirondack Program’s carbon footprint and estimated it to be about 4
tons of CO2e per full-time community member per semester, see Fig. 1. This was
defined through carbon accounting for food, heat, electrical use, transport
during the semester (but not to and from the campus) for the full community.
It did not include contributions from infrastructure such as the campus
buildings and methane emissions from composting, See below for more
discussion.

Figure 1.  The main contributions to the carbon footprint of the Fall 2016 HAP
program. The label ‘cars’ refers to the use of student vehicles for all travel
during the fall, but not to and from campus; ‘suvs’ represents the footprint
of the program vehicles based on actual mileage; ‘food’ represents our
estimate for the footprint of food purchases; ‘heating’ is a rough estimated
footprint for heating the — site buildings based on New York averages; ‘guest
speakers’ refers to the footprint of the travel to and from the site, adjusted
for multipurpose trips; and ‘power’ is the carbon footprint of the electrical
energy consumed based on energy mix in the [local area].

It is easy to see that transportation dominates the program’s footprint. The
transportation (personal “cars” and program “suv’s”) results from the
structure of the internships, food sourcing, and recreational activities. If
reducing the carbon footprint of the program is a goal, reducing the
transportation portion is probably the single most effective step. This can be
obtained for instance by clustering program internships in the Keene - Lake
Placid area so that students can both carpool more and can travel fewer miles.

The chief sources of uncertainty in the Program’s footprint come from
relatively poor heating and food production data. Although our landlord was
generous with access to the energy suppliers, ultimately the — heating data
was not complete enough to use. We used average New York numbers for heating.
In any case since the program extends only about one month into the heating
season, this contribution to the footprint is not large. The other big gap in
our data is the footprint of Essex farm (and other local) food. This is highly
uncertain and we used a mix of US and UK studies in our estimate.

It is early days yet for the carbon footprinting of colleges and universities
is in its infancy and comparisons may be fraught with complications. The
location of a campus plays a large role in the footprint due to heating and/or
cooling. Nevertheless as a point of reference, one careful study of Lancaster
University found about 2.5 tons of CO2e per staff and student member per
semester. (The Higher Education Funding Council for England has set carbon
reduction targets.)

Author Declarations

The author has no conflicts to disclose.

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