Climate change mitigation has traditionally been analyzed as some version of a public goods game (PGG) in which a group is most successful if everybody contributes, but players are best off individually by not contributing anything (i.e., “free-riding”)—thereby creating a social dilemma. Analysis of climate change using the PGG and its variants has helped explain why global cooperation on GHG reductions is so difficult, as nations have an incentive to free-ride on the reductions of others. Rather than inspire collective action, it seems that the lack of progress in addressing the climate crisis is driving the search for a “quick fix” technological solution that circumvents the need for cooperation.

1. Adversarial risk analysis
of the geopolitics of geoengineering
Mark Borsuk
Associate Professor of Civil and Environmental Engineering
Co-Director of the Center on Risk
Duke University, Durham, NC

2. Paris Agreement on
Climate Change
Climate Action Tracker, 2017

4. Geoengineering
• Carbon Dioxide Removal
(CDR):
o Remove CO2 from atmosphere
o Attempts to return climate to
previous states
• Solar Radiation
Management (SRM):
o Reflect sunlight, limit solar energy
reaching Earth
o Does not attempt to return climate
to previous states
o Creates new climate conditions
Climate Central, 2018

5. earth layer technology
space
• space particles
• low orbit solar mirrors, or parasols
• Lagrange point solar mirror
stratosphere aerosol injection – via airplanes, balloons, or artillery
troposphere marine cloud brightening – via fleet of autonomous ships
ocean
surface
• distribute floating white plastic disks, other reflectors
• create microbubbles
land surface
• paint roofs white
• change land use patterns from dark to light
• spread white tarps over the Sahara, or other deserts
SRM: How might we increase the earth’s reflectivity?
Angel (2006)
in Hemming
(2012)

6. earth layer technology
space
• space particles
• low orbit solar mirrors, or parasols
• Lagrange point solar mirror
stratosphere aerosol injection – via airplanes, balloons, or artillery
troposphere marine cloud brightening – via fleet of autonomous ships
ocean
surface
• distribute floating white plastic disks, other reflectors
• create microbubbles
land surface
• paint roofs white
• change land use patterns from dark to light
• spread white tarps over the Sahara, or other deserts
Weather modification history (2015)
SRM: How might we increase the earth’s reflectivity?

7. earth layer technology
space
• space particles
• low orbit solar mirrors, or parasols
• Lagrange point solar mirror
stratosphere aerosol injection – via airplanes, balloons, or artillery
troposphere marine cloud brightening – via fleet of autonomous ships
ocean
surface
• distribute floating white plastic disks, other reflectors
• create microbubbles
land surface
• paint roofs white
• change land use patterns from dark to light
• spread white tarps over the Sahara, or other deserts
Latham et al. (2012) in Hemming (2012)
SRM: How might we increase the earth’s reflectivity?

8. earth layer technology
space
• space particles
• low orbit solar mirrors, or parasols
• Lagrange point solar mirror
stratosphere aerosol injection – via airplanes, balloons, or artillery
troposphere marine cloud brightening – via fleet of autonomous ships
ocean
surface
• distribute floating white plastic disks, other reflectors
• create microbubbles
land surface
• paint roofs white
• change land use patterns from dark to light
• spread white tarps over the Sahara, or other deserts
http://www.geoengineeringmonitor.org/
2018/06/microbubbles-sea-foam/
SRM: How might we increase the earth’s reflectivity?

9. earth layer technology
space
• space particles
• low orbit solar mirrors, or parasols
• Lagrange point solar mirror
stratosphere aerosol injection – via airplanes, balloons, or artillery
troposphere marine cloud brightening – via fleet of autonomous ships
ocean
surface
• distribute floating white plastic disks, other reflectors
• create microbubbles
land surface
• paint roofs white
• change land use patterns from dark to light
• spread white tarps over the Sahara, or other deserts memphite.com
SRM: How might we increase the earth’s reflectivity?

10. Benefits of stratospheric aerosol injection as SRM
• Extremely cheap ($ billions vs. $ trillions)
• Extremely effective (multiple ○C)
• Extremely fast acting (years vs. decades)
• Could tweak dosage easily
• Does not rely on collective
action
• Could prevent dangerous
climate change
• A viable emergency response?

11. Risks of stratospheric aerosol injection as SRM
Certain environmental impacts
• Direct environmental impacts of
deployment
• Less sunlight for solar power
• Sky whitening
• Does nothing for ocean acidification
Uncertain environmental risks
• Unknown earth system effects
• Disparate changes in regional
precipitation patterns
• Risk to South Asian Monsoon
• Risk of regional drought
• Potential for ozone depletion
• Changed photosynthesis rates /
agricultural yields
• Higher acid deposition

12. Ethical Concerns
• “Slippery slope” or “lock-in”
• Disincentive to mitigate?
• Unequal distribution of benefits and harms
• Responsibility for harm?
• Corruptible implementation
• Undue burden on future generations
• Technocratic modification of nature at a
global scale – “humans playing God”
Risks of stratospheric aerosol injection as SRM

13. Disincentive to Mitigate: Moral Hazard or
Risk Compensation?
• Moral hazard: When one party increases risk-taking because
another party has assumed some of the negative consequences
Automobile insurance  Faster driving
• Risk compensation: When one party increases risk-taking in
response to perceiving that risk exposure has been reduced
Airbags  Faster driving
 Public opinion studies suggest that people would be more, rather
than less, concerned about climate change when presented with
the option of solar geoengineering (Reynolds 2019).

14. • Regional differences in intended and unintended effects
• Possibility of unilateral selfish or hostile deployment
• Possible weaponization or counter-deployment
• Sudden stopping problem
The Economist
Governance Concerns

15. Game Theoretic Framing
• GHG mitigation as a “public good”
 “Free-rider” and “tragedy-of-the-commons”
 Socially sub-optimal
• Climate change as “collective risk social dilemma”
 Risk of catastrophe a motivation for collective action
 Potential for social optimality
• Solar geoengineering as “quick fix”
 “Free-driver”
 Again, socially sub-optimal
https://blog.thebookingfactory.com

16. Player 2
mitigate nothing
Player1
mitigatenothing
2
2
-2
1
1
-2
-1
-1
Climate Change as
Prisoner’s Dilemma

17. Player 2
mitigate nothing
Player1
mitigatenothing
2
2
-2
1
1
-2
-3
-3
Climate Change as
Collective Risk Social Dilemma

18. Player 2
nothing SRM
Player1
nothingSRM
-1
-1
2
-1
0
-1
1
1
When mitigation is no longer an option,
SRM becomes dominant strategy

19. Player 2
mitigate nothing SRM
Player1
mitigatenothingSRM
2
2
-2
1
1
-2
-1
-1
2
-1
0
-1
1
1
SRM may also be dominant when
mitigation remains an option
3
0
0
3

20. But, if one nation does NOT have SRM as an option…
Does this make the situation “adversarial”?
Player 2
mitigate nothing SRM
Player1
mitigatenothingSRM
2
2
-2
1
1
-2
-1
-1
2
-1
0
-1
1
1
3
0
0
3

21. SRM changes the incentives for international cooperation on
climate change:
• Two-nation analyses indicate that relative efforts at mitigation
versus SRM are dependent on asymmetries in nations’
preferences and climate sensitivities.
o If nations are symmetric or if expected damages are low,
mitigation will be reduced in expectation of future SRM
(Urpelainen 2012, Moreno-Cruz 2015).
o But, if nations are highly asymmetric or damages are large,
SRM may lead to greater mitigation by one nation to avoid
future use of SRM by the other (Moreno-Cruz 2015)

22. To date, these theories have not been tested against actual
human behavior.
 We are planning a set of experimental games using subjects from both
the general public and experienced UNFCCC delegates.
• Players in a group must decide whether to contribute to a “group account,”
representing a public good.
• If total contributions to the group account meet a target level, then a
“catastrophe” is avoided (loss of remaining endowments).
 To this basic model, we add a generic “quick fix” using a modified version of
the “volunteer’s dilemma”.
• This allows any individual group member to “pull the trigger” on a
technological solution.
• This decision has an immediate cost to the “volunteer,” but will lower the
probability of catastrophe.
• The quick fix may have additional downside risk to group members.

23. Research Questions (single round):
1. Does the presence of a single-actor, “quick fix” solution induce
greater cooperation or does it further promote free-riding?
2. How does heterogeneity in endowments (wealth) impact quick fix
solutions and cooperative behavior?
3. How well can players coordinate behavior with respect to quick fix
solutions to collective action problems?

24. Multi-round:
1. Do players reserve a quick fix solution as a last resort, or implement it
before it is strictly necessary?
2. What impact does the threat of terminating the quick fix technology
in the future have on actions and outcomes?
3. Do players take advantage of the opportunity to reduce technological
risk over time through learning?

25. Broader Applicability
• Other technological “quick fixes” to collective risk social dilemmas:
• Gene editing (vs. public health measures) to confront
disease;
• Blockchain (vs. transparency) to prevent fraud;
• Surveillance cameras (vs. neighborhood watch
programs) to thwart crime;
• Smart guns (vs. training or social norms) to avert
accidental shootings.

26. • Is the situation “adversarial”?
• Lack of common knowledge on:
• Utilities
• Probabilities of success
• Attacker-Defender isn’t quite right
• First-mover?
Question:
To what degree might ARA shed light on this situation?

27. Thank you to the Duke University Office of the Provost for Collaboratory Project Funding
Project members and affiliations:
Mark Borsuk, Tyler Felgenhauer, Varun Mallampalli Duke, Engineering
Juan Moreno-Cruz University of Waterloo, Economics
Todd Cherry, David McEvoy Appalachian State, Economics
Jonathan Wiener, Billy Pizer Duke, Law, Public Policy, and Environment
Jennifer Kuzma, Khara Grieger NCSU, Public and International Affairs
Stephan Kroll Colorado State, Economics
Steffen Kallbekken CICERO, Center for International Climate Research, Oslo
Thank You
mark.borsuk@duke.edu