Witnessing for the Middle to Depolarize - IA de Investigación especializada en el MIT

Testimonio para que el medio se despolarice
the Climate Change Conversation

Robert H. Socolow

Witnessing for the middle seeks to depolarize contentious public issues and to cre-
ate effective coalitions. It reveals neglected facets of a problem, clarifies the stakes,
reduces hype, and facilitates the engagement of people largely on the sidelines. Re-
garding climate change, many forms of middle-building are under way, notably in-
cluding the scenario-making that reveals alternative pathways to some specific goal.
This essay explores two additional vital middle-building conversations, both fo-
cused on the goals themselves. One conversation addresses how to learn faster about
how our planet can harm us. The other conversation focuses on the various ways
that we can harm ourselves while pursuing nominal solutions to climate change.
The two themes are complementary. The more plausible the risks of dangerous cli-
mate change, the stronger the case for risky solutions.

T he title of this Dædalus issue is “Witnessing Climate Change.” I presume

“witnessing” in this instance to be the secular form of a religious concept,
requiring forceful speaking or writing that promotes action on behalf of

some societally significant issue.

Usually, I think, people would call someone a witnessing professional only if
he or she is taking what is regarded at the time as a radical position and is accept-
ing personal risks. Jim Hansen alerting the U.S. Congress to global warming in his
1988 testimony is an apt example of a witnessing scientist. So, también, is Linus Paul-
ing leading the campaign in the early 1960s to stop atmospheric testing of nucle-
ar weapons because of the inevitable negative consequences of radioactive fall-
afuera. And Sherry Rowland and Mario Molina in the mid-1970s pressing the case
for banning production of chlorofluorocarbons, a popular class of specialty chem-
icals then widely perceived to be benign, that they realized would destroy strato-
spheric ozone.

In all three cases, these spectacular interventions required stepping into a
void. But what if the subject at hand has already been extensively debated and the
conversation has become highly polarized? In such situations, there is value in
a different kind of witnessing, “witnessing for the middle.” It is witnessing, ser-
cause it is provocative and disruptive, and its intent is to drive social change. Pero

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

it does not require advocating what at the time are considered extreme positions.
En cambio, witnessing for the middle searches for new ground: fresh conversations
where neglected facets of the problem can be revealed. This middle-building is
not an end in itself, but a lubricant. Its objective is to facilitate involvement on
the part of people largely on the sidelines, so as to produce a more widely shared,
fuller understanding of a problem and, thereby, to diminish polarization. Middle-
building can become self-reinforcing.

One goal of this essay is to expand the conceptualization of witnessing so that

“witnessing for the middle” is included.

In the case of climate change, two packages of ideas are in contention. Excelente-
ly oversimplifying, in one package, the goal is to stave off imminent disaster, y
the move away from fossil fuels cannot be too fast; fortunately, there are specific
attractive solutions at hand, notably solar power, especially in its distributed rath-
er than its centralized form. Además, success may well bring a desirable shift
away from consumerist values toward what used to be called “voluntary simplic-
ity.” In the other package, dangerous climate change is distant, even inconceiv-
capaz, so there is no urgency whatsoever; economic growth based on coal, oil, y
gas is tried and true; alternatives can prosper only with excessive government in-
intervención; and if a move away from fossil fuels must, después de todo, prove necessary,
centralized energy solutions – especially nuclear power – are the preferred tech-
nológico. Amory Lovins, a leading energy analyst for the past half-century, labeled
this polarity the “soft” versus the “hard” path in his classic 1976 essay in Foreign
Affairs,1 and the polarity is still very much with us.

Important middle-building efforts to reduce this polarization have been in
place for decades. One major effort, not the subject of this essay, promotes the
visualization of alternative “scenarios” (pathways to the future) that mitigate cli-
mate change to some specified extent. In these scenarios, strategies evocative of
both the hard and soft paths gain and lose market share as their costs evolve, de-
cade by decade, perhaps out to 2050 o 2100, often in the presumed presence of
a policy that imposes a rising price on greenhouse gas emissions. Technologies
of energy supply and use are always modeled, but often nowadays so is the food
sistema, as well as technologies that deliberately remove carbon dioxide from the
atmosphere. A scenario can apply to a corporation, a city, a country, or the world.
The result is what scientists call an “existence proof,” the discovery of what would
need to be done. Scenarios have brought climate change to many new audiences.
My interest in this essay is to explore two other middle-building exercises, menos
appreciated but crucial for finding our way forward. They illuminate not what is
required to reach some goal but the merits of the goals themselves. How can we
decide whether a goal is too strict or too lax? To answer this question requires un-
derstanding two kinds of risks with opposite implications: the risk that the earth
is extremely sensitive to what we do day-to-day (the higher this risk, the more

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

stringent the targets we should strive for) and the risk associated with our solu-
tions going wrong (the higher this risk, the stronger the argument for more modest
objectives). Juntos, the two complementary themes capture the reality that cli-
mate change above all requires risk management, including hedging against both
kinds of risks.

The first of these conversations addresses the urgent need for climate science
to become more ambitious. (I mean “climate science” to encompass all fields that
bear on the physical and biological features of the planet relevant at the global
escala, including the many implications of human activity; cada vez más, this do-
main is also called “Earth systems science.”) I have two kinds of ambition in mind:
1) giving priority to the hard question of how quickly very bad outcomes could
show up (like fast sea level rise) y 2) recruiting large numbers of researchers
now working on fundamental problems in many relevant areas (chemists, physi-
cists, computer scientists, experts in control theory, to give four examples) but so
far showing little interest in climate change.

The other conversation is about the dark side of “solutions” to climate change
and the need for vigilance. For precision, the conversation needs a time frame,
which in this essay is the next ten to twenty years. In that period, several strategies
to combat climate change (notably, nuclear power, land managed for carbon, y
geoengineering) could create havoc on a par with climate change itself, if imple-
mented heedlessly.

A modern version of the Hippocratic Oath provides a metaphor for the
two-sided reasoning this essay seeks to encourage: “I will apply, for the benefit
of the sick, all measures that are required, avoiding those twin traps of overtreat-
ment and therapeutic nihilism.”2 In medical treatment, many of us are acquaint-
ed with such fateful choices: A drug with promise has strong side effects. Admin-
ister it, or opt for another drug less likely to succeed but with milder side effects?
There is some irony in middle-building exercises that are explorations of ex-
tremes. Yet the argument is quite general: people will agree on the importance of
anticipating the worst that can happen. Such concerns bring people together in
times of war.

The middle-building bearing on climate change that I am recommending must
not be construed as an excuse for delay. Addressing climate change aggressively is
an urgent matter. “It is essential to know more” does not imply “wait for more in-
formation.” Rather, the question I am posing is: what else could we be doing that
is likely to be productive?

By emphasizing the importance of exercises that invite heterogeneous partici-
pation, I am countering the view that building a “movement” is a sufficient strat-
egy for limiting climate change. A movement intentionally creates polarization,
porque, as Gus Speth, one of my generation’s most effective environmental lead-
ers, explained to me, it “needs victims and villains.” It is deeply judgmental. A

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

climate change movement would be self-defeating if it were to stifle a critical and
more embracing public discourse.

We need both middle-building and movement-building. They complement
entre sí. As many of us learned from protesting during the Vietnam War, solo
when the near-left finally joined the far-left could the war be stopped. Witnessing
on behalf of instant dramatic action on climate change has been productive: Tiene
primed the pump. To bring about forceful and coherent activity going forward,
sin embargo, I believe that witnessing for the middle will be essential.

W here am I coming from? I have engaged with climate science and cli-

mate solutions in numerous ways over the past half-century. En 1971,
in my early thirties, I left a faculty job in theoretical physics (quarks)
at Yale for a new faculty position in Princeton University’s School of Engineer-
ing and Applied Science. I had become fascinated with the idea, then completely
new to me, that we humans are changing our planet in immensely disruptive ways
by doing ordinary things. I committed myself to following this idea wherever it
led. The job at Princeton, newly minted, came with the expectation that I would
invent interdisciplinary research related to energy and the environment. I have
focused on solutions to climate change, including energy efficiency, nuclear pow-
es, wind and solar power, and low-carbon energy from fossil fuels. I have ranged
widely across the university, problem-driven rather than discipline-driven. Para
the past two decades, my office and academic home have been in the Princeton
Environmental Institute, a university-wide multidisciplinary unit dominated by
climate science.

I trace my need to witness to my secular and religious schooling: a progres-
sive high school run by the Ethical Culture Society and an iconoclastic Hebrew
School run by the Jewish Reconstructionist Society, both committed to fostering
nonconformity and the student’s social conscience. Además, Reconstructionist
judaísmo, which affirms a rebellious blend of modernity and tradition, taught me
to cultivate the middle. My fascination with global issues was fostered by a year-
long travel fellowship spent in Asian and African countries transitioning to inde-
pendence. My skepticism when I confront advocacy on behalf of some solution
to climate change derives from being a lawyer’s son who heard repeatedly: “My
job is to help my client think about what he does not want to think about. If some-
thing can go wrong, it will go wrong.” As for my specific conviction that fresh con-
versation can transform knotty problems, please allow me to tell four stories (uno
paragraph each).

My initiation into environmental problem-solving in 1969 centered on the
conflict between developers seeking to build a major international airport halfway
across the Florida peninsula west of Miami and environmentalists determined to
protect the flow of water to the Everglades at the peninsula’s southern end. Mi

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

contribución (together with my then Yale physics colleague, John Harte) was to
highlight the interests of other land developers: those who were about to create
cities on the peninsula’s west coast that would require substantial inland stand-
ing water to protect their water supplies. The jetport would jeopardize such water
reserves. When they and other Gulf Coast interests weighed in, President Nixon
decided against the airport and, en 1974, the 720,000-acre Big Cypress National
Preserve was established instead.3 In the language of this essay, a middle-building
exercise had broadened the discussion and had enabled more of those with a stake
in South Florida to imagine alternative futures.

My first multidisciplinary project at Princeton in the 1970s was one of the ear-
liest field studies of energy use in mainstream residential housing.4 We sought to
understand the roles of design, construction, and occupant behavior by instru-
menting actual homes. We deliberately chose average buildings–in this case, re-
cently built row houses for middle-income families–which led to our group being
attacked from two directions. The architecture community was dismayed that we
were not studying the distinctive buildings that architects design, buildings that
have enduring significance. Advocates for social justice told us it was close to im-
moral not to focus on the housing of the poor in inner cities, where the needs were
so compelling. I answered that we hoped to contribute toward reducing the total
energy use in all buildings, and ordinary buildings dominate that total. En efecto,
our project stimulated a fresh conversation about energy use in buildings that
spawned a major national effort to develop higher performance windows, luz-
En g, and appliances in every kind of building. It also prodded electric and natural
gas utilities to include feedback to the customer (graphical comparisons of pres-
ent and past consumption, Por ejemplo) in their monthly bills, which has raised
awareness.

Starting in 1983, with several others, I organized a decade-long collaborative
project with Soviet (and then Russian) counterparts focused on efficient energy
use in buildings and industry.5 The impetus for that project was President Rea-
gan’s speech calling the Soviet Union an “evil empire” and communism “the fo-
cus of evil in the modern world.” In that speech, I foresaw the beginnings of a pro-
cess that would demonize Russians and gradually reduce our inhibitions against
obliterating them. I recalled jumping off small rocks in Central Park in Manhattan
at age six or so, with my two index fingers pulling my eyelids outward, shouting
“banzai,” as we American boys were being carefully taught to demonize the Jap-
anese. Scientists on both sides, similarly frightened by the invocation of “evil,"
developed fresh conversations, of which this was just one example. Our project
led to some new energy-efficiency initiatives in the Soviet Union. In the United
Estados, we needed to defend ourselves against charges of helping the enemy.

De 2000 until 2019, I codirected (with Steve Pacala, an ecologist) a large uni-
versity-wide research program sponsored by BP, a major oil company. Some envi-

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

ronmental activists are baffled that I enjoyed working with BP and continued the
relationship in spite of the 2010 Deep Horizon accident and oil spill. The payoff
for me has been the opportunity to influence BP’s executives. My colleagues and
I provide a safe place for them to ask basic questions, and we provide a counter-
narrative that refutes what they hear in industry settings. Their visits to Princeton
almost always include a tour of the walk-in freezer with ice cores from Antarctica
that chronicle, in their trapped bubbles of old air, the oscillations of the atmospher-
ic carbon dioxide concentration through the ice ages. We inoculate these business
leaders against their own credulity, and they begin to modify their company.

These four middle-building experiences lead me to believe that the two risk-
focused exercises I briefly introduced earlier will be similarly effective in gener-
ating fresh conversations that lead to social change. I elaborate first on dangerous
feedbacks in the earth system and then on misdirected climate solutions.

I f the world addresses climate change forcefully, nations will spend trillions of

dollars over the next few decades to overhaul the world’s current energy sys-
tem and to repurpose the current uses of land. We are preparing to swap an
energy system that currently is 80 percent coal, oil, and natural gas, in favor of one
in which these fuels become minor players. We are considering dedicating cur-
rent pastures and farmland to energy crops and harvesting solar energy and wind
at nearly continental scale. We are creating plans to relocate coastal communities.
We are taking the first steps toward placing the control of climate change into our
own hands (“geoengineering” the planet).

It is truly remarkable that at a time when such monumental transformations
could lie in our immediate future, there is hardly any strong advocacy for deepen-
ing our understanding of how we are affecting our planet: not even for additional
satellites, more probes of the deep ocean and glaciers, more sensors in the forests.
Normalmente, when a corporation takes on a new line of business, it develops a re-
search capability to buttress its new investments. And when a country develops
new allies or enemies, it spends heavily on understanding their cultures and lan-
calibres. But for climate change, the urgency of substantially improving the knowl-
edge base is scarcely part of public discourse today. The complacency about cli-
mate science is anomalous.

To be sure, climate science already captures our planet’s behavior well enough
to motivate decisive action. Sin embargo, climate science at present can only par-
tially delineate what is in store for us. Severe climate change could show up slowly
or quickly. This is the clear message of the reports of the Intergovernmental Panel
on Climate Change (IPCC), which summarize the state of the science roughly ev-
ery six years. The IPCC repeatedly warns us that far less is known than would be
desirable about the amount of climate change the world will be contending with a
decade from now, and half a century from now. Even when human contributions

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

are fully specified, the worst and best plausible outcomes for the future of human-
ity consistent with current science are very different.

When the stakes are so high, why is the climate science enterprise so near-
ly invisible to the public, and why does it have so few champions? A partial ex-
planation lies in the stances of those at both poles of a basic argument about cli-
mate change. Many climate activists insist that “the science is settled.” They fear
that calling attention to what still could be learned will undermine the case that
we already know enough to act. They may also be wary of politicians espousing
“more research” as a way to postpone an effective policy response. en el otro
pole, those whose goal is to forestall action regularly argue that climate science
is so politicized that it provides no guide at all; for them to urge a more ambi-
tious program, they would need to concede that the climate science enterprise is
redeemable.

A broadly supported climate science enterprise would prioritize the need to
understand how soon very large negative impacts could afflict humanity. Mucho
depends on the many feedbacks within the climate system, each of which can ei-
ther amplify climate change (a positive feedback) or suppress it (a negative feed-
atrás). A positive feedback occurs when increases in atmospheric carbon dioxide
warm the Arctic, leading the permafrost to disgorge more carbon dioxide that
warms the Arctic further. Another positive feedback occurs if, on a warming plan-
et, some low clouds start to fade away, and the extra sunlight reaching the earth’s
surface removes more clouds. A negative feedback occurs when extra carbon di-
oxide in the atmosphere stimulates the growth of forests, which in order to grow
must take carbon dioxide from the atmosphere. The future strengths of these and
similar feedbacks dominate our uncertainty about the future climate.

A multifaceted climate science effort might “retire” some currently salient
risks. We may learn that a particular positive feedback is nearly certain to remain
pequeño, but that another may well become debilitating. To be sure, deciding how
much to weight the planet’s worst changes requires a prior effort to sort out the
meanings of “worst.” This can be accomplished only by blending in the insights
of the social sciences and the humanities. Many severe changes to the planet in
physical terms can be made less costly by investments in resilience, comunal-
catión, and governance. There is also a need to take into account who will suffer
mayoría. Middle-building to anticipate and prepare for extreme climate change re-
quires all hands on deck.

At its most extreme, a positive feedback becomes a tipping point that produc-
es radical changes in the entire climate system. (The unbearable noise produced
by a microphone and a speaker when they get too close to each other is the re-
sult of a feedback that has crossed a tipping point.) My colleague, Steve Pacala,
calls the positive feedbacks of the climate system “monsters behind the door.” It
seems that no monsters are yet among us: climate feedbacks are operating nearly

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

as they have operated in the past and are not changing quickly. But what if one or
more monsters escape? The late Martin Weitzman posed this question quanti-
tatively within the context of cost-benefit analysis. He pointed out that although
his fellow economists had long assumed that the average responses of our planet
deserve nearly all the attention, plausible nasty behaviors of our planet could ac-
tually be paramount reasons for action.6

Imagine a counterfactual in which the global climate resembles the current cli-
compañero, with overall warming, shrinking Arctic ice, and the other features that now
alarm us, but climate science hardly exists. The atmospheric concentration of car-
bon dioxide has risen to today’s level, but scientists have not discerned its key role.
We are not in the counterfactual state because of some fortunate decisions in the
history of science. En 1958, geochemist Charles David Keeling began measuring
the atmospheric carbon dioxide concentration high up on the Mauna Loa volcano
on the island of Hawaii. En ese tiempo, many scientists thought this was not a sen-
sible idea, expecting the concentration to be patchy, reflecting variable wind pat-
terns that would sometimes bring distant industrial emissions into the measuring
instruments and sometimes not. Keeling and those who supported him guessed
bien, and the results were reliable. At about the same time, a few far-seeing sci-
entists created new institutional capabilities to coordinate simultaneous studies
of Earth from many places. The International Geophysical Year of 1957–1958 pro-
duced Antarctic ice cores that revealed the level of carbon dioxide in the atmo-
sphere through eight ice ages. Keeling’s Mauna Loa record and the Antarctic ice
cores are cornerstones of the climate science edifice. Each is a great story, wor-
thy of inclusion in new curricula at every education level, from elementary school
through college.

En breve, we are deeply in the debt of the climate scientists, a few thousand peo-

por ejemplo. Without them, we would be flying blind.

Why do I feel so driven to call for a more ambitious climate science effort, como
a primary response to the high societal risks from climate change? During my
short period in theoretical physics, culminating in five years on the Yale Phys-
ics faculty, I saw the norms of science at their best: openness and welcoming,
contention and resolution (the Big Bang versus continuous creation, for exam-
por ejemplo), error correction, the winnowing of the central from minor issues by the art-
ful back-of-the-envelope calculation, and deliberate strategies (like the double-
blind experiment) that inhibit the self-confirmation bias that leads people to find
what they want to find. Fundamentally, I believe that science is a privileged way
of knowing, that science provides humanity’s most reliable searchlight as we
navigate troubled waters.

Respectivamente, I find it portentous that participation in climate science is on the
minds of so few scientists in neighboring disciplines. I can point to some wonder-
ful exceptions, but I wish that a greater number of senior investigators in neigh-

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

boring fields were redirecting their research and urging their students to join
a ellos.

I conjecture that this distancing by scientists in neighboring disciplines can be
attributed in part to their disinclination to give the benefit of the doubt to the find-
ings of climate science that they read about in the popular press. I have heard such
skepticism in countless conversations about climate science over the years with
scientists and engineers in other fields, especially in physics. Much of this distanc-
En g, as best I can determine, is a response to the politicized messaging around cli-
mate science. Great distress spread through the American Physical Society (el
professional society of American physicists), por ejemplo, when one of the Soci-
ety’s public statements said that evidence for human-induced climate change was
“incontrovertible.” Many members were appalled. Después de todo, no finding in science
can be beyond controversy. The history of physics is replete with revisions of pre-
vious orthodoxies. The Society decided to revisit the statement, and “incontro-
vertible” was set aside.

A specific source of the scientists’ misplaced skepticism is the widely promul-
gated claim that “97 percent of climate scientists” believe that currently observed
climate change is at least partially human-induced.7 The statement is probably an
underestimate. But if the goal is to persuade a scientist that some specific research
community is conducting its work according to the norms of science, assertions
eso 97 percent of scientists in that community believe X (no matter what X is) son
counterproductive. Science isn’t about believing, and it isn’t about voting; cada
good scientist leaves room for doubt. When a scientist in another field hears “97
por ciento,” she worries whether this is a field seeking consensus rather than search-
ing for disruptive insights; she worries, incluso, that there may be coercion. De
my perch, I find that the norms of science are scrupulously practiced and well de-
fended by climate scientists. Still, no other area of science is shackled by anything
resembling 97 por ciento, as far as I know.

It is sobering to learn, sin embargo, that the “97 percent” argument has been
singularly effective in persuading lay audiences that climate change science is
well-grounded science, not up for grabs. It directly addresses the counterargu-
ment that there is no consensus at all among climate scientists, which has been
the weapon of choice for interest groups seeking to undermine initiatives respon-
sive to climate change. It is not surprising, por lo tanto, eso 97 percent is so preva-
lent. Evidently, el 97 percent argument is being heard entirely differently by pub-
lic and professional audiences.

T he second middle-building exercise I am advocating in this essay ad-

dresses the solutions to climate change. The two-sided reasoning in the
Hippocratic Oath is with us again. The burden of proof is on those who
would take an option off the list. Sin embargo, there must be room not only to say yes

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

to a solution, but also to say no. A useful word is “conditionality”: the constraints
política- makers should impose when they facilitate the deployment of any solu-
ción. Another word used for these constraints is “guardrails.”

In evaluating solutions, engaged citizens like you and me need to be wary, pero
also to keep an open mind. Within a decade or two, there may be some exciting
new technologies, and some countries may have adopted stringent emission-
reduction policies (a very high carbon price or its equivalent) that transform en-
ergy and land-use competitions. Por otro lado, some solution may have been
introduced at too fast a pace, in the sense that it has induced a level of resistance
that requires starting again.

The world has a portfolio of solutions, as Steve Pacala and I illustrated with an
ecumenical analysis in 2004.8 The conversation about solutions is actually many
parallel conversations, each focused on a single important pathway. Pacala and I
called these low-carbon options “stabilization wedges,” conveying that they have
the potential to grow steadily to reach a climate-significant scale from a small
base. Cuantitativamente, a full wedge is a strategy that reduces the global carbon diox-
ide emissions rate fifty years from now, relative to what it otherwise would be, por
the equivalent of 10 percent of the current emissions rate.

To keep this essay within a reasonable length, I discuss several of the wedg-
es being taken seriously today, but by no means all of them. Not addressed are
the many lifestyle choices made by the prosperous in all countries that affect cli-
compañero, such as diet, travel, and the acquisition of possessions;9 I do discuss family
tamaño. I omit hydropower and geothermal energy, two important electricity supply
wedges. I also do not consider hydrogen-related wedges. Suffice it to say that sev-
eral strategies involving hydrogen (a carbon-free fluid) could become important,
because hydrogen can be produced in many ways and can displace fossil fuels in
many of their current roles in industry and transportation. Hydrogen competes
with electricity and is disadvantaged in that competition because hydrogen re-
quires a new energy infrastructure.

Every wedge offers opportunities for middle-building conversations. Abajo,

for each wedge, I identify such conversations.

Energy efficiency and electrification. Sharp reductions in energy consumption are
essential in a climate-responsive world. Fortunately, deep trends in technologies
have long pointed toward lower energy use. New materials, new sensors, and new
data-processing algorithms (in aggregate, “smart” technologies) are enabling a
host of relatively risk-free technological and social innovations that fulfill human
needs with minimal involvement of the beneficiary. To cite a single insufficiently
celebrated example, the highly energy-efficient light-emitting diode (LED) is dis-
placing most other lighting technology.

When it comes to reducing carbon dioxide emissions, energy efficiency is
joined at the hip with the electrification of the economy. The reason is that the

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

use of oil and gas as fuels cannot be eliminated with energy efficiency alone. A
two-step shuffle holds center stage: substitute electricity for the oil or gas, mientras
in the same time period greatly reducing the carbon dioxide emissions associated
with producing the electricity. Shifting from the gasoline-powered to the electric
car is probably the best example of a wedge based on this two-step shuffle: el
battery- powered vehicle is poised to transform transportation, but the carbon di-
oxide emissions from driving won’t fall much, en todo caso, if the electricity charging
the car’s battery is produced from coal.

In the way, nonetheless, are societal inertia, misaligned economic incentives,
and mistrust of innovation. An apt example is the challenge of overhauling the
ways that buildings are designed and constructed. The unrealized opportunities
are transnational: the many complexes of apartment buildings currently under
construction in the expanding cities of the industrializing countries are locking
in much unnecessary energy consumption by copying the suboptimal practices
and policies that shaped comparable projects built decades ago in now industri-
alized countries: notably, the “first-cost bias” that ignores all costs incurred after
occupancy. The obstacles are similar in transportation, heavy industry, agricul-
tura, and other economic sectors. Middle-building conversation would focus on
ways to accelerate the realization of energy-efficiency wedges, sector by sector.

A broad conversation would also encourage a search for ways to assure a bal-
ance between promoting low-carbon options and protecting individual liberty.
The recent opposition to the elimination of most incandescent light bulbs from
A NOSOTROS. markets provided a taste of arguments that lie ahead, many of which will be
more difficult to dismiss. En efecto, a similar pushback may emerge over policies
designed to end all cooking with gas in favor of cooking with electricity. I worry
about zealotry on the part of the proponents of energy efficiency. An apt quote is
from John Maynard Keynes: “Madmen in authority who hear voices in the air are
distilling their frenzy from an academic scribbler of a few years back.” Any cam-
paign to restrict the use of air conditioning or airplane travel, Por ejemplo, will re-
quire careful listening, not frenzy.

Fewer people. The demographic transition (falling birthrates) has substantially
reduced climate change over the past fifty years, and is expected to continue to do
entonces. Parents exhibit a nearly universal preference for fewer children as they become
wealthier, to such an extent that the populations in an increasing number of coun-
tries are already falling, and the global population may well head downward at
midcentury. All else being equal, a smaller population brings with it the consump-
tion of fewer resources, less crowding, and more room in the atmosphere for the
emissions of future generations. Sin embargo, a falling population can be unnerving
and lead a government to bribe or coerce parents to have more children than they
desear. Granted, the demographic transition creates a population that grows steadi-
ly older on average, a challenge already with us. And surely, populations can fall

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

too quickly. One task for the middle-builders is to examine transitions that align
falling populations with social stability. Por ejemplo, how might governments in-
centivize more of the healthy elderly to remain contributors to the economy?

Solar and wind power. The dramatic reductions in the costs of solar and wind
power over the past two decades have created an expectation that they will be
the workhorses of the future global energy system. Both are growing rapidly. Re-
notablemente, the owner of a single solar panel providing refrigeration and cell-phone
charging at her remote village hut is benefiting from the same feats of semicon-
ductor science and manufacturing as the suburban household drawing power
from a rooftop array or a million-panel facility in a distant desert. And platforms
for wind turbines are marching offshore into steadily deeper water, much as plat-
forms for oil and gas drilling did earlier.

Obstacles to expansion are appearing, sin embargo, as solar and wind power gain
market share. The best solar sites aside from deserts are pristine south-facing hill-
sides (in the Northern Hemisphere), the best onshore wind sites are ridges, y
the best offshore wind sites are within view of coastal communities–assuring re-
sistance to intrusions on landscapes and seascapes and counter-pressures to pre-
serve the wilderness experience. Similar siting conflicts may thwart the march of
high-voltage power lines across hundreds of miles of countryside to connect these
remote locations to major population centers (replacing the transport of the chem-
ical energy in coal, oil, and natural gas by rail and ship and pipeline). Greater com-
pensation for affected communities will reduce hostility in some situations. Es
highly probable, sin embargo, that location-related concerns will diminish the compet-
itiveness of wind and solar power, as they do other energy sources. Middle-build-
ing conversations would get out ahead of these place-based controversies.

Wind and solar power, unlike most other energy sources, are not at our beck
and call. Shortfalls measured in seconds and hours can be accommodated with
the help of batteries. But shortfalls measured in week-long stretches of wind lulls
or cloudiness (o ambos) will require responses that come, at least partially, de
the users of electricity. Especially interesting and fraught, consumers may be
asked to forego the luxury of instant gratification of their demand for electrici-
ty no matter what the cloudiness and windiness outdoors. A more supple energy
system may evolve that promotes behavioral accommodation (washing clothes
only on sunny days and drying them outdoors, Por ejemplo, as was the norm in
my childhood). Although technological strategies to store electricity or heat for
long periods of time are available in many locations, the ultimate contributions
of wind and solar electricity will be much larger if consumers tolerate–even wel-
come–weather-driven modifications of their behavior. Adapting to intermitten-
cy is a good topic for middle-building.

Capture of carbon dioxide from fossil fuel power plants and other industrial facilities. Un
important low-carbon strategy is to keep out of the atmosphere the carbon diox-

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

ide produced during the combustion of coal, or oil, or natural gas at (eventually)
every centralized facility where these fuels are burned.10 In this process, the car-
bon dioxide is extracted from the exhaust-gas mixture heading for the chimney,
before it reaches the air outside. Entonces, the carbon dioxide is piped into a geologi-
cal formation deep underground where it can be stored at least for centuries. (Un
alternative to burying the carbon dioxide is to make a durable material out of it.)
To contribute a wedge, a new below-ground industry would need to become com-
parable in scale to the current oil and gas industries. Emergent problems include
the risk of triggering an earthquake during carbon dioxide injection, which seems
already to be slowing deployment in Japan. There is also the potential, in poorly
characterized storage sites, for upward leakage of carbon dioxide into ground wa-
ter. These problems are not insurmountable.

The political implications of so-called “carbon dioxide capture, almacenamiento, y
use” are intriguing. This wedge enables the fossil fuel industries to contribute
solutions to climate change and enlarges the potential pro-mitigation coalition. Él
makes the winding down of the fossil fuel era a less precarious undertaking by cre-
ating new assignments, still consistent with strong climate goals, for the current
entrenched labor force producing and distributing gas, oil, and coal, and it allows
a repurposing of much of the existing infrastructure.

This wedge has few fans, sin embargo, and not because it has proven to be infea-
sible. En efecto, a modest carbon dioxide pipeline infrastructure already exists, y
promising variants of the key technologies are arriving. Yet the coal, oil, and natu-
ral gas industries provide lackluster support, unpersuaded that governments will
sustain the necessary incentives. Al mismo tiempo, many activist environmental
organizations oppose the strategy. Some argue that, on the basis of current prac-
tices in the fossil fuel industries, one should expect regulatory capture and lack of
transparencia. Others go further, arguably motivated as much by ending the fossil
fuel era as by slowing down climate change. They rightly see this wedge providing
an escape route for fossil fuel in a “decarbonized” world, and they simply do not
want this option to succeed. Sorting out the merits and demerits of carbon diox-
ide capture, almacenamiento, and use is yet another promising middle-building exercise.

Direct capture of carbon dioxide from the air. Carbon dioxide can be removed di-
rectly from the air with chemicals, just as it can be removed from industrial ef-
fluent (the low-carbon wedge just discussed). Sin embargo, only one in twenty-five
hundred molecules in the air is carbon dioxide, as compared, Por ejemplo, con
one in about twenty-five molecules in the exhaust gas at a natural gas power plant.
Como resultado, the capture technologies are very different, and far more hardware is
required to capture the same amount of carbon dioxide from the air than from
flue gas. But the steps subsequent to capture are exactly the same: the carbon di-
oxide must then be either stored or used. This low-carbon option is called “direct
air capture.”

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

Direct air capture is a “negative-carbon” strategy, meaning that it reduces the
amount of carbon dioxide in the atmosphere. Several decades from now, directo
air capture and other negative-carbon strategies may be deployed at such a large
scale that they drive the carbon dioxide concentration of the atmosphere down-
ward. For the next few decades, sin embargo, this wedge will be hampered by the large
amounts of energy required to drive its associated mechanical and thermal equip-
mento. In many locations today, the quantity of carbon dioxide emitted into the
atmosphere in conjunction with running an air-capture facility would be compa-
rable to the quantity of carbon dioxide that the facility extracts. The argument for
building direct air capture projects now, while the world’s energy system is only
slightly decarbonized, is to gain experience and buy down the costs.

Negative-carbon strategies offer ways to cancel the most recalcitrant emis-
siones, like those from airplane jet fuel. Corporations are already offering prod-
ucts with “net-zero” carbon dioxide emissions by tying a product to a negative-
carbon project and asserting that the emissions associated with making and using
the product are “offset” by atmospheric carbon dioxide removal. Large compa-
nies and start-ups are already teaming up to conduct the first negative-carbon
demonstrations. Extensive use of third-party verification and the resolution of a
host of nettlesome accounting issues will be required for carbon offset markets to
flourish at a climate-significant scale. Middle-building can create the consensus
required to formulate the rules of the road.

In my opinion, neither energy efficiency, nor solar power, nor wind power, nor
fossil energy use accompanied by carbon dioxide capture, nor direct removal of
carbon dioxide from the atmosphere has a downside as ominous as three further
climate-driven energy strategies that conclude this section: nuclear power, bio-
carbon, and solar geoengineering.

Nuclear power. Fifty years ago, I believed that the case for deploying nuclear en-
ergy instead of fossil fuels would prove to be so compelling that it would lead to
a broad disavowal of nuclear weapons by the world’s nations, a durable taboo on
their use, and steady progress toward nuclear disarmament. Bastante, the opposite
has happened. Nuclear weapons are desired by more countries today than fifty
years ago and even a decade ago. The global nuclear power wedge is perilous be-
cause national nuclear power programs provide cover for nuclear weapons devel-
opment and make nuclear war more likely.

Conditionality in this instance means forestalling any major expansion of
global nuclear power until such time as there are global institutions that man-
age the nuclear fuel cycle so well that there is no ancillary promotion of nuclear
armas. This probably necessitates the international ownership of all uranium
enrichment and nuclear fuel reprocessing wherever either is pursued, as advocat-
ed by Mohamed ElBaradei when he was director general of the United Nations
International Atomic Energy Agency.11 It also requires serious progress in delegit-

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

imizing nuclear weapons, and the retention in each successive generation of the
understanding of just how horrible nuclear war is.

In an essay in the Fall 2009 issue of Dædalus “On the Global Nuclear Future,"
my nuclear scientist colleague Alex Glaser and I struggled with the merits of glob-
al nuclear power as a route to reduced climate change. After conceding that “the
upper limits of climate change are terrifying, amounting to a loss of control of
the climate system as positive feedbacks of various kinds set in,” we nonetheless
“judge the hazard of aggressively pursuing a global expansion of nuclear power
today to be worse.”12 Alex and I still agree with what we wrote then.

Middle-building exercises would address not only connections to nuclear weap-
ons, but also the escape of radioactivity from nuclear facilities. The latter could re-
sult either from an accident in peacetime, or from a terrorist attack, or from being
targeted in a war. Desde 1986 accident at Chernobyl in the then Soviet Union
(documented brilliantly in the recent book Midnight in Chernobyl) y el 2011 ac-
cident in Fukushima, Japón, one may infer that the regulatory process is so prone
to capture by the nuclear industry that major releases of radioactivity cannot be
excluded.13 Moreover, a nuclear power plant accident has a distinctive feature, evi-
dent in the responses to those two disasters, which is contagion: an accident at any
nuclear plant creates strong pressure to shut down every other nuclear plant.

Biocarbon. There is several times as much carbon in the earth’s forests and grass-
lands and soils (“biocarbon”) as in the atmosphere (where nearly all of it is in car-
bon dioxide). In the course of a year, plants use photosynthesis to take carbon from
the atmosphere in the growing season and return carbon to the atmosphere as
they decay; in most places these two flows approximately balance out. Actualmente,
there is considerable interest in biological wedges that shift that balance slightly,
moving some atmospheric carbon into vegetation.

Planting a new forest is one way to accomplish the transfer. What needs to be
taken into account so that this specific undertaking does not go awry? Considerar,
Por ejemplo, that you are a forester working in a country that is heavily subsidiz-
ing the removal of carbon dioxide from the atmosphere. Your boss buys an exten-
sive land parcel and puts you in charge of planting a new forest there; she tells you
that storing as much carbon as possible on the land is your only objective. Qué
do you do? Establish a monocrop? Pour on fertilizer? Be inventive.

Ahora, change roles. You are a policy-maker in that same world, designing a
market that is rewarding carbon removal, and you are motivated by broad social
and environmental goals. What conditionalities do you insert into the carbon
market in the interest of eliciting the land use and forestry you welcome and de-
terring outcomes you decry? You could prohibit using land now in agriculture,
so as not to restrict the food supply. You could require the biodiversity value of
the land to be taken into account, as well as the forest’s effect on local water, y
whether there are forest dwellers nearby whose lives will be disrupted. The subsi-

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

dy could be only for “net carbon,” where the carbon dioxide emissions associated
with chainsaws and trucks are subtracted from the carbon stored. If the forest is to
be actively managed for timber, you could credit not only the carbon in the forest
but also the carbon from that forest stored in the beams and trusses of buildings
that may stay in place for a hundred years.

This vignette gives a glimpse of the complexity of biocarbon solutions. El
story is similar if ethanol for vehicle fuel is produced from corn or sugarcane, dis-
placing gasoline. Or if crop and forest “wastes” are processed at bio-refineries to
produce climate-friendly chemicals.

A particularly interesting variant, biological energy with carbon dioxide cap-
ture and storage, is another negative-carbon strategy, like direct air capture. Pho-
tosynthesis transfers carbon from the air into a living plant, which is then har-
vested and burned to generate electricity. If chemicals capture most of the carbon
dioxide in the exhaust of this biomass-fueled power plant, and this carbon dioxide
is then stored for the long term, the net result is to reduce the amount of carbon
dioxide in the atmosphere.

At the global level, mitigating climate change primarily through manipula-
tions of the biosphere requires the use of a significant fraction of the earth’s land.
The underlying reason is that photosynthesis is an extremely inefficient process
for converting sunlight into energy. Consequences for global food production and
biodiversity can be devastating without careful planning. In contrast to some of
the other options just discussed, extensive conversations about opportunities and
threats related to most biocarbon wedges are already underway.

Solar geoengineering. If we human beings can now modify our planet inadvertent-
ly by pursuing everyday activities, it should not be surprising that we also now have
the capability to manipulate the planet deliberately with targeted measures: a
“geoengineer.” In particular, we have the capability to reduce incoming sunlight to
compensate, at least partially, for our current warming of the planet. One scheme
increases the reflection of incoming sunlight by modifying the upper atmosphere
(la estratosfera). A closely related concept makes the tops of clouds brighter.

The immediate decisions today are about small-scale field research. Many ad-
vocate prohibition. They doubt that human beings will ever use tools wisely that
can manipulate the whole planet; En particular, they see no plausible route to glob-
al governance. Some of these critics see a slippery slope where small-scale exper-
iments with no lasting impact lead to some much larger experiment that creates
the very disaster it was meant only to learn about. They are opposed by others
OMS, in support of field experiments, insist on the need to be prepared; the earth
could soon reveal itself to be at the upper end of sensitivity to human perturba-
ciones, and it is therefore incumbent on the research community to move promptly
to develop the means to counter the adverse changes. Geoengineering might be
able to retard sea level rise, Por ejemplo.

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

Disquieted by how poorly we understand our planet, I see the cart in front of
the horse here. The systems that are candidates for manipulation through geoen-
gineering (la estratosfera, clouds, and several others) are the same as the sys-
tems requiring deeper understanding to fathom the risks of human-induced cli-
mate change in the absence of geoengineering. A prudent research plan would
give priority to how our planet works now, and it would treat whatever benefits
accrue to geoengineering as subordinate. Inevitably, much of the new knowledge
of the earth that will be acquired in the near future will be “dual use,” a phrase in-
voked in the sphere of national defense to describe technology with military and
nonmilitary applications. This commonality between arms control and geoengi-
neering alerts us to the need to guard against risk assessments of geoengineering
that are bloodless and feature excessive quantification.

I expect that the mission of solar geoengineering will expand beyond planetary-
scale cancelation of global warming to include objectives bearing on human com-
fort and convenience at much smaller scale, and I fear the consequences for other
species. How will they fare if we humans use solar geoengineering to remove hur-
ricanes and heat waves and droughts? Countless species occupy ecological niches
that depend upon climate extremes: the plant that flowers only during hot spells
or that thrives in a flash flood, Por ejemplo. Many of these niches will disappear,
possibly to our long-term detriment, if we are not able to resist making the crook-
ed straight and the rough places plain.

Conversations about geoengineering are likely to be the most contentious of
all those I have proposed. Geoengineering engages profound feelings about hu-
man destiny. It requires us to ask what level of control of the planet human beings
ought ever to have.

T he risks of solutions were not considered in the global diplomatic process

leading to the Paris Agreement negotiated in 2015, which identifies the
world’s goals for climate change management. Only the risks of climate
damage were motivating. Implicitly, the diplomats were expressing their confidence
that the science and engineering community is clever enough to get us there safely.
The overarching Paris goal is simple to understand. Referencing the average sur-
face temperature of the planet, it affirms the desirability of constraining future activ-
ity so that this temperature never rises even as much as 2 degrees Celsius (3.6 degrees
Fahrenheit) above its value in “pre-industrial” times (a period of several centuries
ending around 1800, during which this temperature was roughly constant). Simpli-
fying, the Paris goal requires the average surface temperature to stay “well below”–
language used in the agreement–16 degrees Celsius (acerca de 61 degrees Fahrenheit),
because the pre-industrial average surface temperature was about 14 degrees Celsius
(acerca de 57 degrees Fahrenheit). The temperature rise thus far has taken us about half-
way: the average surface temperature has risen close to 1 degree Celsius.

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

The nearly universal acceptance of the “two-degrees” goal is a triumph of di-
plomacy. Worldwide, it has spawned countless supportive quantitative commit-
ments and placed palpable pressure on corporations and governments to begin
the required rapid transformations of technological infrastructure and land use.
The two-degrees goal is a social construct, sin embargo, not a scientific finding. Sci-
ence has not identified any line in the sand, a boundary between safe and unsafe.
We do know that climate change gets steadily more dangerous as the earth warms.
But as far as anyone knows now, 2 degrees Celsius is not a tipping point. As best I
can tell, even the affirmatively risk-driven global climate science program I have
advocated is not likely to pin down tipping points, even though it will improve our
understanding of the earth’s many feedbacks. Our planet is just too complicated.
The world may go past the two-degrees target. In already industrialized coun-
intentos, the target requires overhauling entrenched institutions and replacing infra-
structure long in place. In industrializing countries, the target requires severe de-
partures from historical patterns of development (leapfrogging). The world is not
yet prioritizing either of these challenges. En efecto, the industrialization ahead in
Asia and Africa is a good candidate for another middle-building exercise. In what
proportion, Por ejemplo, will India build coal power and solar power, and what are
the critical determinants of that fateful and imminent choice inside and outside
el pais? Hasta ahora, conversations about such urgent questions are rare.

A world unprepared for exceeding the two-degrees target could succumb to
panic and defeatism. Panic could lead to an uncritical embrace of dangerous solu-
ciones. Defeatism could bring a cessation of effort, even though at no future time
will inattention to climate objectives be preferable to continued concerted action.
Three degrees of warming is immensely safer than five degrees (Celsius! A Celsius
degree is 1.8 Fahrenheit degrees, and five Fahrenheit degrees of average surface
warming is immensely safer than nine degrees). We need to prepare a soft landing
for “two degrees,” in case we turn out to need it.

I s witnessing for the middle an oxymoron? Isn’t it just a way of playing safe?

Can witnessing for the middle ever move the needle more quickly and less re-
versibly than witnessing for an extreme? If witnessing for the middle can re-
configure the debates, clarify the stakes, reduce hype, and create effective coali-
ciones, then yes it can. I have provided two examples of activities that can contrib-
ute to these objectives, both focused on the risks of worst outcomes: in one case,
the risks inherent in our not being able to rule out a very unstable planet, and in
the other case, the risks of misapplied solutions. En esencia, I am advocating for
opening two new conversations.

What conditionalities ought to be placed on middle-building itself? Some will
doubtless argue that the all-encompassing global climate crisis is so grave that un-
compromising extremism is justified: it is appropriate to present the immediacy

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

of the crisis and the goodness of solutions without qualifications. This position
will remind some readers of what Barry Goldwater said in his 1964 presidential
nomination acceptance speech at the Republican National Convention: “extrem-
ism in the defense of liberty is no vice.” What about that sentence was so upset-
ting at that time? Is it less menacing today? Granted, nuance can diminish the
commitment to action. But surely, in dealing with a threat that, however dire, will
likely remain ill-defined for a long while, it is essential to build a resilient climate
change discourse by telling the story straight.

The story is about the collective destiny of humankind on our planet, cual es

a quite new concern. Here is how I would tell the story so far, in four paragraphs.

The planet we inhabit is so small that we are able to change it inadvertently
with everyday activity. Humanity is only just beginning to scope the dramatic re-
visions of current practices that must be pursued on a planetary scale over many
decades in order to sustain our collective well-being and the well-being of Earth’s
other species. The implications are particularly severe for the many nations that
have most of their industrialization ahead of them; as best we know, the planet
cannot stay safe unless they follow novel development paths. Simultáneamente, el
already industrialized countries will need to overhaul their own infrastructures.

Climate science already provides an ample foundation for prompt action that
slows the arrival of climate change. Sin embargo, climate science is incomplete.
Climate scientists are gradually clarifying how the planet works, helped by the
earth itself, which is gradually revealing its secrets. There is ample justification
not only for much more ambitious climate science but also for greater focus with-
in climate science on investigating best and worst outcomes, especially worst out-
comes. Global climate change requires sustained risk management, which in turn
requires ever bolder climate science.

Workable solutions are either at hand or in view. But every solution that mit-
igates climate change can be dangerous, if deployed inattentively at large scale.
Every solution is a strong drug, with known and unknown side effects. Accord-
ingly, we must resist any framing that contends that, in climate change, humanity
faces a single overriding problem and that we must throw caution to the winds to
solve it, subordinating all other objectives. No matter what the proposed solution,
we must investigate every feature that might lead us to reject it. People intuit that
solutions poorly applied could have unappealing consequences for getting and
spending and bucket lists, for family size, for equity, for international security, para
environmental soundness. Vigilance is the name of the game.

The human predicament is universal. All of us alive today, like it or not, are in
the same boat. We share an obligation to protect the earth in order to protect our-
selves and to sustain future generations. It requires an act of faith to believe that the
voyage that lies ahead will be enjoyable, bringing new technologies strikingly supe-
rior to those we have now and greater well-being. The odds are better, sin embargo,

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation

if we pursue the kinds of middle-building that reveal our common risks. I find
hope in the possibility that confronting climate change collectively will gradually
create a global identity that transcends our rampant tribalism.

The story has just begun.

nota del autor

Dedicated to Robert Jay Lifton, a hero of mine, who is also contributing to this vol-
ume. Half a century ago, I joined him in organizing a campus-wide event at Yale
called A Day of Reflection, which started fresh conversations about how scientists
should relate to the military.

An early version of this essay was presented at the Witnessing Professionals and
Climate Change Workshop held at Princeton University on May 12, 2018. I wish
to thank Melissa Lane and Nancy Rosenblum for inventing the conference and for
inviting me to give a talk there. I further thank Nancy for inviting me to write this
essay and for commenting trenchantly on early drafts.

Among the many experts from whom I have inferred general lessons about climate
ciencia, I note especially Isaac Held, Nadir Jeevanjee, Ray Pierrehumbert, V. rama-
swamy, Tapio Schneider, and the late Marty Weitzman.

My journey toward the middle was informed by thousands of conversations
with peers and students, among them Bill Brinkman, Karen Florini, Marc Fleur-
baey, Chris Greig, John Harte, Bob Keohane, Ewan Kingston, Melissa Lane, Aarón
Match, Kian Mintz-Woo, Richard Moss, Naomi Oreskes, Michael Oppenheimer,
Jerry Ostriker, Steve Pacala, Alan Robock, Tapio Schneider, David Socolow, Dennis
Thompson, Elke Weber, Chuck Weiss, and Bob Williams.

I also benefited from sensitive readings of various drafts by Mark Budolfson, Ber-
nie Bulkin, Valerie Karplus, Shoibal Chakravarty, Heleen de Coninck, Felix Creut-
zig, Greg Davies, Ryan Edwards, Judi Greenwald, Klaus Keller, Elena Krieger, Klaus
Lackner, Jonathan Levine, Lynn Loo, Suki Manabe, Marco Masoero, John Mecklin,
Mayank Misra, Amilcare Porporato, METRO. V. Ramana, Noah Scovronick, Dustin Tin-
gley, Frank von Hippel, Fabian Wagner, and Chuck Witt.

A special thanks to Mimi Schwartz, an expert on the craft of storytelling and a
champion of authenticity.

All opinions and outright mistakes are mine alone.

Sobre el Autor

Robert H. Socolow, miembro de la Academia Americana desde 2014, is Professor
of Mechanical and Aerospace Engineering, Emeritus, at Princeton University. Él
co-directed the Carbon Mitigation Initiative at the Princeton Environmental Insti-
tute from 2000 a 2019. He is the editor of Industrial Ecology and Global Change (con

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

149 (4) Fall 2020Robert H. Socolow

Clinton Andrews, Frans Berkhout, and Valerie Thomas, 1994), Saving Energy in the
Home: Princeton’s Experiments at Twin Rivers (1978), Boundaries of Analysis: An Inquiry into
the Tocks Island Dam Controversy (with Harold Feiveson and Frank Sinden, 1976), y
Patient Earth (with John Harte, 1971). He has recently published in such journals as
The Monist, Nature Climate Change, Energy and Environmental Science, and Proceedings of the
Academia Nacional de Ciencias.

notas finales

1 Amory Lovins, “Energy Strategies: The Road Not Taken?” Foreign Affairs 55 (1976): 65–96.
2 This version was written by Dr. Louis Lasagna in 1964. See “The Hippocratic Oath: Mod-
ern Version,” PBS NOVA, https://www.pbs.org/wgbh/nova/doctors/oath_modern.html.
3 John Harte and Robert H. Socolow, “The Everglades: Wilderness Versus Rampant Land
Development in South Florida,” in Patient Earth, ed. John Harte and Robert H. Socolow
(Nueva York: Holt, Rinehart, and Winston, 1971), 181–202.

4 Robert Socolow, ed., Saving Energy in the Home: Princeton’s Experiments at Twin Rivers (Pensa-

cola, Fla.: Ballinger, 1978).

5 Robert H. Socolow and M. ross, Energy Conservation: Proceedings of the Soviet-American Sympo-
sium, Moscow, Junio 1985 (Oxford: Pergamon, 1987). Also published by Pergamon as Energy
12 (3) (1991).

6 Martin L. Weitzman, “Fat Tails and the Social Cost of Carbon,” American Economic Review:

Documentos & Actas 104 (5) (2014): 544–546.

7 John Cook, Sander van der Linden, Edward Maibach, and Stephan Lewandowsky, El
Consensus Handbook: Why the Scientific Consensus on Climate Change Is Important (Fairfax, Leva-
puente, and Bristol: George Mason University, University of Cambridge, Universidad de
Bristol, 2018), https://www.climatechangecommunication.org/wp-content/uploads/
2018/03/Consensus_Handbook-1.pdf; and John Cook, Naomi Oreskes, Peter T. Doran, et
Alabama., “Consensus on Consensus: A Synthesis of Consensus Estimates on Human-Caused
Global Warming,” Environmental Research Letters 11 (4) (2016).

8 Stephen Pacala and Robert Socolow, “Stabilization Wedges: Solving the Climate Problem
for the Next 50 Years with Current Technologies," Ciencia 305 (5686) (2004): 968–972.
See also Robert Socolow and Stephen Pacala, “A Plan to Keep Carbon in Check,” Scien-
tific American 295 (3) (2006): 50–57.

9 Shoibal Chakravarty, Ananth Chikkatur, Heleen de Coninck, Stephen Pacala, Robert So-
colow, and Massimo Tavoni, “Sharing Global CO2 Emission Reductions among One
Billion High Emitters,” Proceedings of the National Academy of Sciences 106 (29) (2009):
11884–11888.

10 Robert Socolow, “Can We Bury Global Warming,” Scientific American 29 (1) (2005): 49–51.
11 Mohamed ElBaradei, “Towards a Safer World,” The Economist, Octubre 16, 2003, https://

www.economist.com/by-invitation/2003/10/16/towards-a-safer-world.

12 Robert Socolow and Alex Glaser, “Balancing Risks: Nuclear Energy & Cambio Climático,"

Dédalo 138 (4) (Caer 2009): 31–44.

13 Adam Higginbotham, Midnight in Chernobyl: The Untold Story of the World’s Greatest Nuclear

Desastre (Nueva York: Simon and Schuster, 2019).

D
oh
w
norte
oh
a
d
mi
d

F
r
oh
metro
h

t
t

pag

:
/
/

d
i
r
mi
C
t
.

metro

i
t
.

mi
d
tu
d
a
mi
d
a
r
t
i
C
mi
–
pag
d

F
/

1
4
9
4
4
6
1
8
5
7
3
2
2
d
a
mi
d
_
a
_
0
1
8
1
6
pag
d

b
y
gramo
tu
mi
s
t

oh
norte
0
8
S
mi
pag
mi
metro
b
mi
r
2
0
2
3

Dédalo, la Revista de la Academia Estadounidense de las Artes & SciencesWitnessing for the Middle to Depolarize the Climate Change Conversation
Descargar PDF