Earth, Humans, and the Trolley Dilemma
Earth, Humans, and the Trolley Dilemma
Dora Chi Xu, Class of 2015
New College House
January 25, 2015
Dora Chi Xu, a geoscience major from China, will work as a post-baccalaureate research
associate at the Earth and Environment Department in F&M, before pursuing an MD/PhD
degree in geology/engineering. She is passionate about groundwater hydrogeology and hopes
that she could eventually contribute to alleviating the global freshwater crisis. She is an
explorer, tree-hugger, outdoor enthusiast, cook, painter, and is involved in African drumming
and dancing, flamenco, and Bollywood dance.
Earth, Humans, and the Trolley Dilemma
Many of you may have already heard about the famous trolley problem:
Suppose there is a trolley that goes out of control and is about to kill 5 people tied to
the railway ahead. You have the option to pull a lever that can direct the trolley to a sidetrack,
where there is only one person. What would you do? Do nothing and let the trolley kill the
five people? Or pull the lever to save them by sacrificing one?
This moral paradox was first introduced by British philosopher Philippa Foot in 1967,
and has been extensively analyzed by numerous psychologists, and neuroscientists (Thomson
1985). Yet, it raises a question that applies as much to human-earth interaction as to the
traditional ethical, philosophical and psychological domains that focus on human-human
interactions. Please keep the trolley problem in the back of your mind, as we will come back
later to this discussion.
As we reflect upon our position in human-earth relation, let’s first take a look at what
the earth looked like at the beginning of human history. For the last 100,000 years, the
temperature on earth has varied incredibly. The last 10 to 12 thousand years, however, have
been remarkably stable in terms of temperature—This period is known as the Holocene era in
geology. With the biogeochemical and atmospheric parameters fluctuating within a relatively
narrow range, the Holocene has been an extraordinary benevolent time for humans,
particularly when considered against the background of our planet’s tumultuous past
(Dansgaard et al. 1993, Petit et al. 1999, Rioual et al. 2001). It is no coincidence that though
human beings have been around for more than 90,000 years, not until Holocene era did we
begin agriculture, and did humanity begin to flourish. Indeed, the end of the last ice age and
the beginning of the warmer and more stable Holocene era has allowed humans to move
freely, and achieve major shift in lifestyle and culture, such as transitioning from hunting and
gathering to farming.
The history of human civilization is a history of constant modification and
manipulation of natural systems for the benefit of mankind. Geologists call this geoengineering. Agriculture, for example, the first and probably the most influential geoengineering, though unplanned in the first place, has been decisive in human evolution.
Agriculture has laid the foundation for economically specialized societies, sedentary living,
and hence permitting the accumulation of possessions, growing population, and further
development of political systems, technology, etc. From an environmental perspective, geoengineering, such as agriculture, has had far-reaching influences on hydrology, vegetation
cover, biodiversity, nitrogen cycles, and climate. Early human activities affected the
functioning of the earth system. The imprints, however, were limited to local or regional
scales (Steffen et al. 2007), because the earth has a capacity to restore equilibrium;
nonetheless, that resilience is limited. Since the industrial revolution, humans have become
the dominant driver of environmental changes and are now effectively pushing the planet
outside the Holocene range of variability for many key earth system processes (Steffen et al.
2007). Indeed, the most essential activities of our society, such as energy and food
production, transportation etc., have so thoroughly altered the world that a new geologic era
Earth, Humans, and the Trolley Dilemma
has been recognized and gaining wide acceptance: the Anthropocene, a new epoch of
geological time characterized by dramatic planetary changes that are precisely linked to
human activities (Crutzen, P. I. and Stoermer, E. F. 2000). Geologists are able to infer the
traits of past epochs from the rocks that were deposited during those time intervals, and
generally the progression from one epoch to another is marked by distinguishable, global
stratigraphic events, such as bulk change in rock composition or mass extinction. Many
scientific studies inferred that our activities have created a biological, geochemical or
sediment signal that will be sufficiently different from that of the Holocene epoch, and will
be preserved as a rock record for millions of years (Syvitski, 2012).
In order to keep earth as a habitable planet, there are non-negotiable lines that we
must not cross. Ample scientific studies enabled 9 planetary boundaries to be identified,
delineating safe operating space for humanity. Transgression of the thresholds may trigger
catastrophic, irreversible consequences within the continental to planetary scale system.
These boundaries involve climate change, ocean acidification, stratospheric ozone, the
nitrogen and phosphorus cycle, global freshwater use, biodiversity loss, chemical pollution
and atmospheric aerosol loading (Rockström et al. 2009). These processes are deeply interconnected, and thus violating one boundary may dramatically affect the position of another.
So, where are we at today? The first estimate on a global scale shows that for at least three of
them, we have already broken through the environmental ceiling:
1) Too much green house gas has been released into the atmosphere, which indicates
that we are on the verge of triggering catastrophic climate change.
2) We have created three times more reactive nitrogen than the planet can sustain. The
disturbance of natural nitrogen cycle has a series of cascading effects from acid rain to soil,
stream and groundwater contamination, costal eutrophication, and decreasing biodiversity.
3) Biodiversity is plummeting rapidly due to habitat loss, climate change, invasive
species, overexploitation, and pollution, which would affect our food and energy
security, and increase our vulnerability to natural disasters (Rockström et al. 2009).
Undoubtedly, such proposed boundaries are preliminary estimates, whose accuracies
are limited by uncertainties and knowledge gaps. However, our actions and choices will to a
large degree determine how close we are to the critical thresholds, or whether we have
crossed them. Instead of offering a roadmap, delineating planetary boundaries merely
represents the first step to identify the directions to which we have the flexibility to choose a
myriad of pathways to respond. If we can keep humanity pressure on the planet within these
limits, then we may avoid pushing ourselves over the edge.
Let’s take a look at climate change as an example. Methane (CH4) and Carbon
Dioxide (CO2) are the major culprits of global warming; in fact, CH4 is 20 times more potent
a greenhouse gas than CO2. The earth has a built in system, called orbital oscillation, which
helps to control the rhythm of periodic variations of CH4 level in the atmosphere. According
to the studies on ice cores in Greenland and Antarctica, 16 CH4 cycles recorded are in close
correlation with orbital variations for the past 350,000 years (Rhodes et al. 2013). However,
the last 8000 years show a widening divergence of CH4 from orbital oscillation, with
insolation (i.e. solar radiation) going down and CH4 going up. Moreover, pollen and lake
sediment functions as another independent proxy for climate. For instance, if the climate
became colder, more water would be locked in the polar ice, and less would be evaporated
from the ocean and transported to the land. Thus, the aridity would cause the forests to die off
and give way to dry grassland. The seeds preserved in the sediment thus enabled scientists to
reconstruct the paleoclimate. The overall drying of mid-latitude climate shown by pollen and
Earth, Humans, and the Trolley Dilemma
lake data indicates that CH4 should be lower, which means decreased global temperature
(Marcia et al. 2003). That is to say, if the climate followed its regular path, we should have
been in the ice age right now. So what happened to the 17th cycle? The answer is agriculture.
The deviation of CH4 concentration from the projected pattern roughly corresponds to the
first cultivation of rice and other grains (Crutzen, P. I. and Stoermer, E. F.: 2000).
Surprisingly, inefficient early farming practices created a larger carbon footprint than we do
today. CO2 also shows a similar divergence from natural patterns around 8000 years BP,
which matches the anomaly of CH4. Early Anthropogenic hypothesis proposed that preindustrial forest clearance, farming and irrigation in Eurasia are more responsible for current
global warming, since they emitted approximately 300 Giga Tons of Carbon (GTC), two
times more than the commonly cited industrial emissions (Crutzen, P. I. and Stoermer, E. F.:
2000). Thus the question becomes: why did the atmospheric CO2 concentration stay at a
relatively stable level during pre-industrial time and did not show significant increase until
recently? The main reason lies in the long-term buffering effect of the ocean, which had
absorbed most of the pre-industrial CO2 until the ocean reaches its capacity
(Ruddiman,2003). If this hypothesis is true, the advent of agriculture by ancient people may
be the true cause of anthropogenic climate change. Since there is a lag time between carbon
emission and global warming, the bitter fruit that we are chewing today was actually planted
8000 years ago, by our ancestors. Does this news give you a chill creeping down the back?
The CO2 that we pumped into the atmosphere by burning fossil fuels has not really shown its
power yet, but the storm is coming soon, and this time the ocean can no longer act as our
protecting umbrella.
Bombarded by the terrible things humans have done that may ultimately poison us
into extinction, I’m sure that many of you, like myself, have been tired of hearing how severe
the problem is, and are eager to learn about solutions to fix it. Let’s revisit the trolley
problem. So the trolley is barreling down the rail, threatening to kill the five people. The first
thing to ask is, how on earth were these five people on the tracks in the first place? There are
plenty of safe places out there to walk and play. In the case of climate change, we tied
ourselves to the deadly track, but it is not fair to simply put the blame on our ancestors. At the
time when there were bountiful resources and a limited population, a slash-and-burn farmer
could easily cut down the forests next door whenever his own field lost fertility. It seems
difficult for them to have come across the idea of conservation, or contemplated what
consequences their actions would have thousands of years later, when the world’s resources
be depleted by a gigantic population.
The most effective way, obviously, is to stop the trolley, but is it stoppable?
Maybe not. With the exploding population and the economic growth of developing countries,
our emissions are increasing exponentially. The projection of the CO2 emission has been
heavily debated, and skeptics argued that environmentalists overestimated the emission just
to make it look as bad as possible. However, emission levels of CO2 are now growing even
faster than what we thought was the worst scenario just a few years ago. In fact, we have
already crossed the CO2 concentration of 350 ppm, deemed one of the threshold, which has
triggered a series of irreversible reactions in other systems (Rockström et al. 2009). For
example, the warming climate has given rise to the melting of permafrost on the Tibetan
plateau and high latitude areas such as the Arctic. This releases large quantities of CH4 that
was frozen in the soil, which feeds the cycle of more warming and more melting. Similarly,
the glacier retreat also exhibits such positive feedback: the melting of glaciers exposes more
dark bare rock, which absorbs more solar radiation than the reflective ice does, and thus leads
to more melting. In this regard, the trolley is ever accelerating.
Earth, Humans, and the Trolley Dilemma
What fuels the engine of the trolley? We have a global economy and civilization that
is built on fossil fuels, and until we shift to a healthy mix of energy resources with the
corresponding infrastructure, the world still runs on oil and gas. The struggle for petroleum
has shaken the world economy, dictated the outcome of wars, and profoundly shaped the way
we lead our daily lives. For example, at current technology level, we cannot find a substitute
for airplane diesel fuel, because no other resources have the equivalent energy density. As the
easy oil comes to an end, people are digging deeper and harder in the realm of
unconventional petroleum. The heatedly debated Keystone XL pipeline and the explosion of
shale gas drilling in Pennsylvania are two examples. Advocates claim that the unconventional
petroleum is a “game changer”, since it contains 200 times the reserves than conventional oil
and gas (Mackenzie, 2012), and the breakthrough in technology has transformed the U.S.
from an energy-importer to an exporter. Besides achieving energy independence, the boom in
unconventional petroleum industry is a strong economic stimulus and creates massive
employment (Sander, Katie, 2014).
However, the benefits that the unconventional petroleum brings cannot outweigh the
trouble that it causes. First, the recovery of shale gas requires a technology called hydraulic
fracturing. It demands energy to pump a large amount of water, mixed with toxic chemicals,
to crack the shale open, artificially enlarging the permeability so that gas can flow out. It has
raised serious environmental problems, such as water usage, pollution, public health issues,
and human-induced earthquakes, to name a few. TransCanada spokesman claimed that the
construction of Keystone XL pipeline will create 42,000 jobs, directed or undirected.
However, such effect is only temporary. After the 2-year construction, the pipeline would
employ about 50 people, primarily for maintenance (Sander, Katie, 2014). Furthermore, the
same fossil fuel interests pushing the pipeline have been cutting, not creating jobs: the top 5
oil companies have reduced their U.S workforce by 11,200 employees between 2005 and
2010, in spite of earning $546 billion profit. Do those who survived the laid-off and working
for the industry get paid higher wages? It turns out that 40% of the U.S. oil industry jobs
consist of minimum wage work at gas stations. Another claimed benefit is to lower local
natural gas price, but low domestic price means better markets elsewhere. Most of the
pipelines in Pennsylvania converge at the port cities in Delaware or Maryland, which allows
for easy export of the natural gas for fast-growing countries like China and India, and even
post-Fukushima Japan.
Above all, the most fundamental problem is that unconventional petroleum is not
necessarily an energy resource, because its payback ratio is close to one. In other words, to
get the energy out, we need to drill the well, pump the water and chemicals in, blow open the
tight shale, extract the oil or gas out, refine it into usable form, and distribute it to where the
demands are high…all of which requires energy from the almost depleted easy oil. Then how
does the petroleum industry make profit? They can make money out of an energy sink thanks
to the heavy subsidy from the government. Why are the renewable energy solutions less
economical compared to petroleum? The renewables will be much more competitive if the
petroleum was not as heavily funded; they will be more popular if they receive more
subsidies and favorable policies. Unfortunately, the tangled relationship between the U.S.
government and the petroleum industry is complicated and involves multiple layers of
bureaucratic and legal ambiguity, making commitment to transforming current energy
structure potentially difficult. The dominance of money in modern U.S. politics has now led
to what termed as “quarterly democracy”, where officeholders running for reelection are
required to publicly report their fundraising every three months. Even though we have the
Earth, Humans, and the Trolley Dilemma
capacity for long-term planning, such constant systematic stress has forced elected officials to
focus intently on short-term horizons. This is especially precarious during a period of rapid
change. Not all changes happen in gradual, linear fashion; sometimes the potential pressure
can build up without visibly manifested until the critical threshold is reached. It’s as if we are
all passengers of an airplane, whose pilot is steering without a reliable navigational
instruments, and is instead pushing random buttons, hoping that we can somehow
miraculously wind up landing in New York City. To quote Al Gore, the author of An
Inconvenient Truth: “By tolerating the routine use of wealth to distort, degrade, and corrupt
the process of democracy, we are depriving ourselves of the opportunity to use the” last best
hope” to find a sustainable path for humanity.” The world’s need for intelligent, clear, valuesbased leadership is greater now than ever before-and the absence of any suitable alternative is
clearer now than ever before.
Even as we work our way to build a low-carbon economy, petroleum yet plays an
indispensible role. Take solar energy development in Arizona for example, with more than
300 days of sunshine each year, and sizable wide-open, flat landscape that is ideal to install
large-scale solar panels, the potential of solar power harvesting is enormous. According to a
report by National Renewable Energy Laboratory, Arizona has the capacity to produce as
much electricity from Solar Energy as the state consumes each year. Nevertheless, there ain’t
no such thing as a free lunch. First of all, such estimate does not take into account of input
energy and associated environmental impacts. Panel manufacturing requires Rare Earth
Element, most of which currently come from China, and has already caused ecological
degradation problems associated with mining. It also demands energy to transport the
necessary raw material, to melt the glass, and to make the panels, which has a finite life span.
Another factor to consider is the energy loss on the current inefficient transmission gridlines.
According to the 2005 data from the Energy Information Administration, the US lost $19.5
billion on energy distribution (EIA, 2005). Other concerns revolve around the disturbance
(such as the shading effect) on local ecological systems, potential vandalism problems, etc.
Therefore, when taking a cradle to grave analysis, for every single form of renewable
resources, we need to explore it, confirm it, recover it, convert it into usable form, distribute
it, and dispose its waste after its lifetime, all of which requires energy that currently come
from oil or gas. With the low-hanging fruit having already been picked, our energy future
depends on how do we make the most out of the remaining fossil fuels. We can either invest
them in transforming our energy structure to a self-sustaining one, or use them to tap into the
unconventional petroleum, which is an energy black hole-- until the point that we do not have
any energy to get more energy out.
Are there other solutions to slow down the trolley or direct it into different directions?
Some geo-engineering ideas have been proposed, many of which seemed crazy at first
glance, but have recently attracted more attentions, as international efforts to limit carbon
emissions have failed. I will briefly discuss two most popular ones. The first solution
involves pumping seawater into the atmosphere to create clouds that reflect more sunlight.
Stephen Salter from the University of Edinburgh and John Latham from the National Center
for Atmospheric Research in Colorado are the major promoters of this project. Their research
shows that an increase in the albedo, that is, the reflectivity of the clouds by just 3% could
offset previous human’s contributions to global warming (Salter, Sortino, and Latham 2008).
According to Salter and Latham, the method will calls for a fleet of 1500 boats that spray 50
m3/s of seawater into the atmosphere. This might seem like a promising and simple method,
but it begs the following questions: From where will the energy to run the ship and pump the
water originate? How would the clouding effect influence the monsoon cycle, on which
Earth, Humans, and the Trolley Dilemma
millions of people rely for living? How about its impact on the aquatic system? Still, others
argue that this is just a Band-Aid to the problem, since no one knows for sure how long the
effects of the clouds would linger, and it does not lower the actual atmospheric CO2 levels at
all. In fact, even if we stop pumping CO2 now, it will still take the earth about 200 years to
absorb all the CO2 that is already out there. What about carbon capturing?
Current carbon sequestering technology is very expensive, and involves injecting
fluid CO2 into subterranean cavities, which have the risk of triggering earthquakes if the CO2
push open pre-existing faults. Yale scientists have presented another model showing that
storage of CO2 in mafic rock- namely Magnesium (Mg) and Iron (Fe) rich rock-may be
among the safest options (Viktoriya et al., 2013). Their theory is simple: weathering of mafic
rock (e.g. basalt in Hawaii), the most ubiquitous on earth surface, consumes CO2. How do
we know this will work? Earth’s history proved so. About 440 million years ago, the collision
between offshore volcanic islands and the ancient North American continent, formed a series
of mountain ranges, which constitute the current Appalachian Mountains. Such a mountainbuilding event, called the Taconic orogeny, plunged Earth into an ice age (Phil Berardelli,
2014). Why? Because the igneous rock created by the collision and volcanic activities,
quickly reacted with CO2 in the atmosphere, which caused the earth to cool and the last ice
age to begin. Can we mimic the result of the Taconic orogeny and fix the global warming
problem? At the current rate, about 10 Giga tons (Gt) of carbon is produced annually, most of
which come from burning fossil fuels and deforestation. Is it feasible to offset 10 Gt of
Carbon per year by weathering mafic rock? Let’s do a mass and energy balance calculation:
Natural weathering can remove about 0.1 Gt C/yr (Cotton et al., 2013). Although warmer
temperature increases this rate, natural carbon sequestering is still vanishingly small.
However, we can speed up the process by crushing mafic rocks and spreading them to expose
to water and atmosphere. Theoretically, it will take 15 Gt of mafic silicate to remove 10 Gt of
CO2 (IEA, 2009). What does this figure mean? Comparing to coal mining, which has an
annual production of 8 Gt, it requires a mafic rock mining industry about 2 times the size of
global coal mining industry. The required energy is about 4.7 to 9.4 Quadrillion Btu per year,
about 0.8% of the world total primary energy consumption, at a cost of 0.01% of GDP. If we
take the energy input and emission generated from mining, crushing, and transportation into
consideration, and subtract that from the CO2 sequestered, we can calculate the offset
efficiency: 90%. So, should we do it? The efficiency is favorable, and the method is
energetically possible. Is it economically viable? There is yet no profit in the silicate mining
industry, unless we achieve an international treaty to make it a lucrative commodity. Who
will pay for it? Are there any other environmental impacts? How do we anticipate and
quantify them? To acquire mafic rock in such large quantities, we might need to grind up 1/3
of Australia (which has the world richest Fe-Mg rich minerals, the Australians wouldn’t be
happy though). Even if we sacrifice 1/3 of Australia, would it be enough to reverse global
warming? Since the world economy continues to grow, and the carbon emission is increasing
exponentially, what if we eventually run out of mafic rock? “Well, don’t worry,” as my
geology professor Tim Bechtel remarked sarcastically, “humans are good at finding
engineering solutions, the moon is full of mafic basalt.”
To fix a problem we came up with an engineering solution, which triggered
unintended consequences; to fix the unintended consequences, we found a new engineering
solutions to it, which, of course, can give birth to even more unintended consequences…Does
our interaction with earth bear a striking resemblance with the old nursery song: There was
an old lady who swallowed a fly, to catch the fly she swallowed a spider, to catch the spider
she swallowed a bird, then a cat, a dog, a cow, and a horse…she’s dead in the end, of course!
Earth, Humans, and the Trolley Dilemma
Nevertheless, it is important to think seriously about geo-engineering because we may need
to use it as a fast and temporary risk control but not as a substitute for long-term action. This
is due to the enormous amount of leverage that geo-engineering can bring, and there are
times that we may want a fast solution to bring the fever down. Opponents argue that the
knowledge that geo-engineering is possible makes climate change less fearsome, and
therefore a weaker commitment to cutting emissions today (Bunzl, 2008). That is what David
Keith, a Canadian environmental scientist, called a moral hazard, and that is one of the
underlying reasons why it is so politically hard to talk about this. But you do not make better
policies by hiding things in a drawer.
Now we shall return to the trolley problem that I posed in the beginning of the paper.
The trolley is unstoppable. Do we have a moral obligation to prevent a disaster from
happening? No matter which way we choose, there are always trade-offs. Who should
decide? Based on what criteria? Would the greater good always outweigh the minority? How
do we know whether or not our good-intended actions could lead to even more disasters?
There are always doubts in science, and the intrinsic uncertainty lies in how complex the
system will behave, such as its feedback mechanisms and the interactions among variables. In
other words, we may possess dots of knowledge, but we do not fully understand how the dots
are connected and how exactly they interact with one another. One single action may trigger
a chain of reaction, producing cascading, irreversible consequences. To phrase the question
another way: How do we do what we do, without knowing that we don’t know? Should we
wait? Can we afford to wait? These are complicated questions and have no clear-cut answers,
but the science necessary to make consequential decisions, should come from our generation.
From a socioeconomic perspective, it is hard to put a brake on this very high inertia fossilfuel based-economy, because simply finding out a better, more powerful way to do things
does not necessarily guarantee readily acceptance. The problem could be absolutely soluble
in terms of science and engineering, but it is politically hard because there are always
winners and losers. We need a broader debate, a debate that involves industry leaders,
scientists, engineers, politicians, economists, philosophers, writers, and general public. It is
time that we think clearly about the obvious trend that are ever gaining momentum; it is time
that we reason together and attend to the powerful changes that are now underway.
Why should we care? German pastor Martin Niemöller has a famous poem:” First
they came for the socialists, and I did not speak out—Because I was not a socialist. Then they
came for the trade unionist, and I did not speak out—Because I was not a trade unionist. Then
they came for the Jews, and I did not speak out—Because I was not a Jew. Then they came
for me—and there was no one left to speak for me.” The cowardice and lament for the 20th
Century German Holocaust applies as much to today’s apathy toward global warming and
other issues confronted by the entire human race. Is climate change merely a threat for lowlying countries like Bangladesh or the Maldives? Why do we need to care whether the
Greenland’s ice melting would wipe out some of the largest cities from the world map?
Should we always consider us in the position of pulling the lever? Or are we actually the one
on the track? The following Native American proverb put it succinctly:” We do not inherit
the land from our ancestors; we borrow it from our children.”
We are the children.
Earth, Humans, and the Trolley Dilemma
Acknowledgement
I’m grateful to professor Suzanna Richter, who introduced me to the Marcellus Shale
controversy in first year seminar and opened my eyes to a whole range of environmental
issues. I’m deeply indebted to professor Tim Bechtel, who taught me everything from
introductory geology, unconventional petroleum, to geo-engineering and karst hydrogeology.
Thanks also to my dear friends Cinthia Liu, Lydia Baird, Andy Foley, and Aaron Blair for
proofreading my paper and offering their valuable insights.
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