What Experiments to Block Out the Sun Can’t Tell Us
Using technology to fix climate change requires careful research—but
that’s easier said than done.
By Bina Venkataraman <http://www.slate.com/authors.bina_venkataraman.html>
The historic agreement forged in Paris among 195 countries in December
holds the promise of triggering a global shift to combat climate
change—and harbors a hidden warning.
Regardless of what happens next, the Paris accord is a triumph of
diplomacy among nations that have starkly disagreed in years past about
who is responsible for cutting carbon dioxide emissions—and who should
bear the cost. But success in heading off the worst climate disruptions
hinges on whether countries fulfill the pledges each made leading up to
the Paris talks and make bolder ones this decade. The teeth come in the
form of sunshine and shame: The accord requires transparency and
monitoring of emissions from each country. And it relies on countries to
be motivated by the ignominy they would face if they reneged.
There is a danger that shame will not be enough. In the United States,
Republican presidential candidates have already vowed to undo President
Obama’s climate change policies, including the pivotal Clean Power Plan
<http://www.epa.gov/cleanpowerplan/clean-power-plan-existing-power-plants>
that regulates emissions from the electricity sector. Senate Majority
Leader Mitch McConnell warned that the Paris accord stands on shaky
ground; he thinks, contrary to most credible legal experts, that the
Obama power plant rules are illegal. It’s unlikely the prospect of
infamy would deter a climate change–denying president or Congress from
shattering the U.S. pledge. That’s the kind of consideration that
pertains to the reasonable and rational.
What would happen if the U.S. failed to keep up its end of the
agreement? The United States’ actions greatly affect other countries’,
because the world sees us as responsible for the mess everyone’s in.
Leaders of developing countries and island nations hold industrialized
countries responsible for the reckless carbon binges of past decades
that have pushed low-lying territories to the brink of disaster. The
Obama administration summoned all its leverage to persuade other
countries to develop without emitting as much carbon as we did on our
path to economic dominance. In Paris, the U.S. had to play the parents
who say, “Do as I say, not as I do,” while also promising a generous
allowance.
The United States faces strong internal pressure to keep burning fossil
fuels, reflected in our divisive politics; other nations—especially
island nations like Tuvalu and Kiribati—face strong pressure to keep the
planet cooler at any cost. The seas are already rising. The mood is ripe
for private-sector companies or individual nations to seek drastic ways
to change the climate, either to avoid the cuts agreed to in Paris or to
hedge their bets in case of political failure. Yet absent from the Paris
agreement and absent from U.S. political discourse is any robust
discussion of what could be a growing threat, especially after the
November presidential election: that countries, people, or businesses
will take it upon themselves to directly cool the planet.
Experiments in geoengineering have already been tried. In 2012, a rogue
scientist dumped 120 metric tons of iron into the Pacific Ocean to grow
plankton blooms to remove carbon dioxide from the atmosphere. He
violated no law. In 2015, China announced plans
<http://www.commondreams.org/news/2015/01/14/china-goes-rogue-artificial-weather-scheme>
to seed clouds with chemicals to boost rainfall, building on its
standing artificial weather program. Based on the cost and potential
cooling effect of various geoengineering technologies, the most likely
scenario today is that someone would attempt to change the atmosphere by
pumping sulfate aerosols in the stratosphere—to reflect sunlight away
from Earth. (This technology, dubbed solar radiation management, is
being promoted and researched by a small but vocal group of scientists.)
Now is the time, with the wind from Paris at our backs, to set
international norms for how geoengineering technologies are tested and
deployed and to consider how the U.S. would navigate a global landscape
in which different nations want to engineer the climate to different
ends. Would Russia want to warm Earth beyond 2 degrees Celsius to turn
Siberia into a fertile growing region? Will Vanuatu find a sympathetic
billionaire to shield the planet from the sun so that sea levels do not
rise so high?
More research on geoengineering could help us anticipate the possible
ways the technologies could be used. But we should be clear about what
each stage of research can actually show us. In order to prove that the
technique of reflecting sunlight with sulfates can cool the planet
consistently without terrible consequences, experiments must ultimately
be large enough in geography and long enough in time frame. And those
characteristics raise the possibility for widespread, unintended
consequences. Rutgers climate scientist Alan Robock has argued
<http://www.sciencemag.org/content/327/5965/530.full> that trials in the
atmosphere won’t show a significant climate response, “unless an
experiment is so large as to actually be geoengineering” and lasts at
least a decade. (Experimenters would need to confirm that any changes in
climate were not just coincidental.)
Scientists have studied the effects of volcanoes that temporary cooled
the planet, such as the 1991 Mount Pinatubo eruption in the Philippines.
But incidents in the past cannot simulate what it would really be like
to try to cool the entire planet today with such technologies, over a
time span of not years, but decades. Launching small experiments of
limited duration—or gradual deployment, as has been advocated by Harvard
geoengineering scientist David Keith—may also help advance our
knowledge. But the world should be aware that this method cannot tell us
whether the technology is safe enough or too dangerous to deploy—it
can’t give us the kind of insights that we have, for instance, when we
test a drug for its side effects in a randomized controlled trial. (Even
with that gold standard for assessing risk, we still have cases like
Vioxx, where the dangerous side effects for large populations can be far
worse than what appears in a limited clinical trial. In geoengineering,
we have only one planet, not many patients, and the benefits and risks
are collective, not individual.)
This conundrum of conducting large-scale solar geoengineering
experiments poses an ethical dilemma that cannot be resolved by
scientists alone. We need a robust public debate to ask when and to what
extent it is ethical to experiment with the planet. We need global norms
that take into account the uncertainty and serious risks that solar
radiation management could pose, such as manipulation of weather
patterns and damage to the food supply, air pollution deaths, depletion
of the ozone layer, and other impacts we may not yet anticipate in the
dynamic, complex system that is Earth’s climate. If early experiments
epically fail, will they be counterproductive to the technology over the
long term, like the nuclear meltdown in Three Mile Island?
A recent global summit on gene editing technologies
<https://www.newamerica.org/weekly/should-we-engineer-future-humans/>
hosted by national scientific councils from the United States, the
United Kingdom, and China could provide a model for how policymakers,
ethicists, scientists, and the public can set boundaries on the use of
technologies with unknown and intergenerational consequences. After the
summit, the three councils published principles to guide when the use of
gene editing is sound and ethical, and when it is too risky—namely, when
it poses unpredictable and irreversible impacts for future generations.
While such norms won’t stop rogue engineers, they at least keep the wise
and the willing from unleashing unforeseen consequences. And they can
help scientists navigate the fine line between expanding knowledge and
deploying technologies in the absence of international support.
The chance of success in cutting climate change emissions has never
seemed more palpable. But we should seize the goodwill generated in
Paris to talk about the engineering elephant in the room. The United
States can and should lead not just by making politically determinate
commitments but by anticipating what could happen if we fail to keep up
our end of the bargain.
/This article is part of the geoengineering installment of Futurography
<http://www.slate.com/topics/f/futurography.html>, a series in which
Future Tense introduces readers to the technologies that will define
tomorrow/. /Each month from January through May 2016, we’ll choose a new
technology and break it down. Future Tense is a collaboration among
//Arizona State University/ <http://www.asu.edu/?feature=research>/,
//New America/ <http://www.newamerica.org/>/, and /*/Slate/*/. To get
the latest from Futurography in your inbox, sign up for the weekly
Future Tense newsletter./
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