SOLAR GEOENGINEERING WEEKLY SUMMARY (16 DECEMBER - 22 DECEMBER 2024)
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Solar Geoengineering Updates
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Monthly news summaries about solar geoengineering. Links to scientific
papers, news articles, jobs, podcasts, and videos.
<https://solargeoengineeringupdates.substack.com?utm_source=substack&utm_campaign=publication_embed&utm_medium=email>
By Andrew Lockley
<https://solargeoengineeringupdates.substack.com?utm_source=substack&utm_campaign=publication_embed&utm_medium=email>
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RESEARCH PAPERSStratospheric injection of solid particles reduces side
effects on circulation and climate compared to SO2 injections
<https://iopscience.iop.org/article/10.1088/2752-5295/ad9f93>
Stefanetti, F., Vattioni, S., Dykema, J., Chiodo, G., Sedlacek, J.,
Keutsch, F., & Sukhodolov, T. (2024). Stratospheric injection of solid
particles reduces side effects on circulation and climate compared to SO2
injections. *Environmental Research: Climate*.
*Abstract*
Most research of stratospheric aerosol injection (SAI) for solar radiation
modification (SRM) has focused on injection of \ce{SO2}. However, the
resulting sulfuric acid aerosols lead to considerable absorption of
terrestrial infrared radiation, resulting in stratospheric warming and
reduced cooling efficiency. Recent research suggests that solid particles,
such as alumina, calcite or diamond, could minimize these side effects.
Here we use, for the first time, the
atmosphere-ocean-aerosol-chemistry-climate model SOCOLv4.0, incorporating a
solid particle scheme, to assess the climatic impacts of SAI by these
injection materials. For each substance, we model tropical SAI by means of
constant yearly injection of solid particles, aimed to offset the warming
induced by a high-GHG emission scenario over the 2020-2100 period by 1 K.
We show that solid particles are more effective than sulfur at minimising
stratospheric heating, and the resulting side-effects on the general
atmospheric circulation, stratospheric moistening, and tropopause height
change. As a result, solid particles also induce less residual warming over
the Arctic, resulting in greater reduction of GHG-induced polar
Amplification compared to sulfuric acid aerosols. Among the materials
studied here, diamond is most efficient in reducing global warming per unit
injection, while also minimizing side effects.
Three Pathways to Nonuse Agreement(s) on Solar Geoengineering
<https://www.cambridge.org/core/journals/ethics-and-international-affairs/article/three-pathways-to-nonuse-agreements-on-solar-geoengineering/CC47B8FF9E27CEDDF18FD1A0B151F121>
VanDeveer, S. D., Biermann, F., Kim, R. E., Bardi, C., & Gupta, A. Three
Pathways to Nonuse Agreement (s) on Solar Geoengineering. *Ethics &
International Affairs*, 1-12.
*Abstract*
Recent years have seen increasing calls by a few scientists, largely from
the Global North, to explore “solar geoengineering,” a set of speculative
technologies that would reflect parts of incoming sunlight back into space
and, if deployed at planetary scale, have an average cooling effect.
Numerous concerns about the development of such speculative technologies
include the many ecological risks and uncertainties as well as unresolved
questions of global governance and global justice. This essay starts with
the premise that solar geoengineering at planetary scale is unlikely to be
governable in a globally inclusive and just manner. Thus, the ethically
sound approach is to pursue governance that leads to the nonuse of
planetary solar geoengineering. Yet is such a prohibitory agreement
feasible, in the face of possible opposition by a few powerful states and
other interests? Drawing on social science research and a host of existing
transnational and international governance arrangements, this essay offers
three illustrative pathways through which a nonuse norm for solar
geoengineering could emerge and become diffused and institutionalized in
global politics: (1) civil society-led transnational approaches; (2)
regionally led state and civil society hybrid approaches; and (3)
like-minded or “Schengen-style” club initiatives led by states.
Impact of solar geoengineering on temperature-attributable mortality
<https://www.pnas.org/doi/10.1073/pnas.2401801121>
Harding, A., Vecchi, G. A., Yang, W., & Keith, D. W. (2024). Impact of
solar geoengineering on temperature-attributable mortality. *Proceedings of
the National Academy of Sciences*, *121*(52), e2401801121.
*Abstract*
Decisions about solar geoengineering (SG) entail risk–risk tradeoffs
between the direct risks of SG and SG’s ability to reduce climate risks.
Quantitative comparisons between these risks are needed to inform public
policy. We evaluate idealized SG’s effectiveness in reducing deaths from
warming using two climate models and an econometric analysis of
temperature-attributable mortality. We find SG’s impact on
temperature-attributable mortality is uneven with decreases for hotter,
poorer regions and increases in cooler, richer regions. Relative to no SG,
global mortality is reduced by over 400,000 deaths annually [90% CI: (−1.2
million,2.7 million)] for cooling of 1 °C from 2.5 °C above preindustrial
in 2080. We find no evidence that mortality reduction achieved by SG is
smaller than the reduction from equivalent cooling by emissions reductions.
Combining our estimates with existing estimates of sulphate aerosol
injection direct mortality risk from air quality and UV-attributable cancer
enables the first quantitative risk-risk comparison of SG. We estimate with
61% probability that the mortality benefits of cooling outweigh these
direct SG risks. We find the benefits outweigh these risks by 13 times for
our central estimates, or 4 deaths per 100,000 per 1 °C per year [90% CI:
(−11,23)]. This is not a comprehensive evaluation of the risk–risk
tradeoffs around SG, yet by comparing some of the most consequential
impacts on human welfare it is a useful first step. While these findings
are robust to a variety of alternative assumptions, considerable
uncertainties remain and require further investigation.
Accounting for transience in the baseline climate state changes the surface
climate response attributed to stratospheric aerosol injection
<https://iopscience.iop.org/article/10.1088/2752-5295/ad9f91>
Duffey, A., & Irvine, P. J. (2024). Accounting for transience in the
baseline climate state changes the surface climate response attributed to
stratospheric aerosol injection. *Environmental Research: Climate*.
*Abstract*
Stratospheric aerosol injection (SAI) is a proposed means of climate
intervention that could halt global temperature rise, though it would
imperfectly offset climate change. To estimate this imperfection, it is
common to compare the simulated climate under SAI against that of a
baseline state at the same global mean temperature without SAI. Here, we
combine a recent set of SAI simulations (ARISE-SAI-1.5) in the earth system
model UKESM1, with simulations of idealized abrupt and transient warming
scenarios, to assess the impact of transient warming through this baseline
state on surface climate changes attributed to SAI. We quantify the effect
of temperature stabilisation as the expected change in surface climate
between a climate state under warming and one in quasi-equilibrium at the
same global mean temperature. We estimate that accounting for temperature
stabilisation eliminates the land-sea warming ratio change attributed to
SAI. However, relative to the hypothetical scenario with lower CO2
concentrations that would achieve a stabilised climate at the same
temperature, SAI produces a 69% larger reduction in global precipitation.
Accounting for stabilisation can also meaningfully change the spatial
pattern of surface temperature response attributable to SAI. We repeat our
analysis for the GeoMIP G6sulfur scenario, to show that effects
qualitatively consistent with these findings are seen when comparing the
SAI state against the faster and slower warming baselines of the SSP5-8.5
and SSP2-4.5 scenarios. The changes in climate state attributable to
temperature stabilisation are generally small compared to changes due to
warming since pre-industrial. However, these differences can be significant
in the context of assessing residual changes under SAI because these
residuals are themselves roughly an order of magnitude smaller than the
effects of warming. Our findings have implications for the design and
assessment of future SAI simulations, and for the attribution of changes in
surface climate to SAI.
Producing the Inevitability of Solar Radiation Modification in Climate
Politics
<https://www.cambridge.org/core/journals/ethics-and-international-affairs/article/producing-the-inevitability-of-solar-radiation-modification-in-climate-politics/402F719990D3BE9A4FEC1A68FF85F04B>
Oomen, J. Producing the Inevitability of Solar Radiation Modification in
Climate Politics. *Ethics & International Affairs*, 1-15.
*Abstract*
This essay investigates the fit between solar radiation modification (SRM)
and climate politics. Researchers, activists, and politicians often present
SRM technologies as “radical.” According to this frame, SRM comes into view
as a last-ditch effort to avoid climate emergencies. Such a rationale may
be applicable to the scientists researching the potential of SRM, yet it
only partially accounts for political and policy interest in SRM. In this
contribution, I argue that there is an increasingly tight fit between the
promise of SRM technologies and the global regime of climate politics.
Within this regime, SRM may not be a radical option but is more of a
logical extension of current rationales. I argue that SRM corresponds to
tightly controlled discursive rules within which climate politics operates,
leading to a shifting narrative on the feasibility, desirability, and
necessity of SRM. The ethical implications of this tight fit are threefold.
First, it implies that SRM might be an instrument of mitigation deterrence,
implicitly as much as explicitly. Second, ethical responsibility and
political value debates are at risk of becoming invisible once SRM becomes
embedded in the prevailing regime. Third, SRM use might become inevitable,
despite the good intentions of most people involved.
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WEB POSTSGlobal warming is speeding up. Another reason to think about
geoengineering
<https://www.economist.com/leaders/2024/12/19/global-warming-is-speeding-up-another-reason-to-think-about-geoengineering>
(Economist)Governance of “Solar Geoengineering”
<https://medium.com/@honegger.matthias/governance-of-solar-geoengineering-795aef623bcd>
(Medium)Will Climate Change Become Unbearable When the World Reaches 1.5°C
or 2°C?
<https://srm360.org/article/will-climate-change-become-unbearable-1-5c-2c/>
(SRM360)Scientists deliberate on the research gaps in understanding impacts
of Solar Geoengineering
<https://teriin.org/press-release/scientists-deliberate-research-gaps-understanding-impacts-solar-geoengineering>
(The Energy & Resources Institute)Could SRM Be Weaponised?
<https://srm360.org/article/could-srm-be-weaponised/> (SRM360)Giving Green
Recommends Philanthropic Strategies for SRM
<https://srm360.org/perspective/giving-green-philanthropic-strategies-for-srm/>
(SRM360)Neither climate laboratory nor knowledge vacuum: What’s at stake
for the Global South in the debate around solar geoengineering research
<https://www.science.org/doi/10.1126/science.adt9594> (Science)Solar
Radiation Modification: Ghana begins stakeholder engagements
<https://www.ghanabusinessnews.com/2024/11/29/solar-radiation-modification-ghana-begins-stakeholder-engagements/>
(GBN)Experiments outside the lab come with new responsibilities
<https://www.science.org/doi/10.1126/science.adu7458> (Science)The European
Commission Receives Recommendations on SRM
<https://srm360.org/perspective/european-commission-receives-recommendations-on-srm/>
(SRM360)Is solar geoengineering research having its moment?
<https://www.newscientist.com/article/2461498-is-solar-geoengineering-research-having-its-moment/>
(New Scientist)
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THESISDesign, Development, and Evaluation of Splash-Plate Atomization for
Marine Cloud Brightening
<https://open.library.ubc.ca/media/download/pdf/24/1.0447519/4>
Shahrasebi, M. (2024). *Design, Development, and Evaluation of Splash-Plate
Atomization for Marine Cloud Brightening* (Doctoral dissertation,
UNIVERSITY OF BRITISH COLUMBIA (Vancouver).
*Abstract*
Marine Cloud Brightening (MCB) has been proposed as a technique to produce
local or regional cooling over remote oceans. The underlying principle of
MCB is to artificially enhance the reflectivity and longevity of the
maritime stratocumulus clouds by injecting seawater aerosols at low
elevations (~ 1 km), where they act as cloud condensation nuclei. However,
the presence of giant (1-10 microns) cloud condensation nuclei (CCN) within
the seeded size spectrum expedites precipitation, which may break up the
cloud layer. A critical challenge in MCB is the development of
energy-efficient methods for generating and dispersing CCN of the optimal
size range (30-500 nm).
This thesis investigates the potential of splash-plate atomization (SPA) as
a novel and efficient technique for MCB applications. SPA utilizes jet
impingement on an inclined plate to generate a thin liquid sheet that
subsequently breaks into droplets of a size comparable to the sheet
thickness, rather than the orifice diameter, offering control over droplet
size distribution. An experimental setup has been developed, including a
SPA unit, a sampling room, and instrumentation for characterizing particle
size distribution. To complement the aerosol size measurements, shadowgraph
imaging has been performed, allowing for the visualization and analysis of
the spray dynamics. The performance of the SPA system has been evaluated
under various operating conditions, including different pumping pressures
(1000, 1400, and 2000 psi), different spray deflection angles (75, 60, 45,
and 30 degrees jet deflections), and different plate lengths (edgeproximal
and edge-distant).
------------------------------
*UPCOMING EVENTS**Solar radiation modification: What should Europe’s
strategy be? by Scientific Advice Mechanism to the European Commission
<https://us02web.zoom.us/webinar/register/WN_zMVEie0PThCasf0lFO_FSw#/registration>
| 23 January 2025 | Online**Solar Radiation Modification: What’s at stake
for society? by Scientific Advice Mechanism to the European Commission
<https://us02web.zoom.us/webinar/register/WN_Sra0pIz1Q7KeHjzxHOaMFQ#/registration>
| 03 February 2025 | Online*(NEW) Climate Intervention: Distraction or
Necessity? by Center for Climate Repair
<https://www.climaterepair.cam.ac.uk/events/climate-intervention-distraction-or-necessity>
| 21 March 2025*2025 Solar Radiation Management Annual Meeting by Simons
Foundation
<https://www.simonsfoundation.org/event/solar-radiation-management-annual-meeting-2025/>
| 24-25 April 2025 | New York**The 2025 Degrees Global Forum
<https://substack.com/redirect/8521c00b-652a-4d78-822f-7ae393c57068?j=eyJ1IjoiMjJrMHl3In0.wQQsFypG52typ8FI2nhnJ8eUoUIIkdCkuhmzxNYKtgE>
| 12-16 May 2025 | Cape Town, South Africa**Artic Repair Conference 2025 by
University of Cambridge & Center for Climate Repair
<https://substack.com/redirect/90f81f14-d09c-4418-8d97-c6621d753433?j=eyJ1IjoiMjJrMHl3In0.wQQsFypG52typ8FI2nhnJ8eUoUIIkdCkuhmzxNYKtgE>
| 26-28 June 2025 | Cambridge UK*
Solar Geoengineering Events Calendar <https://teamup.com/ks64mmvtit583eitxx>
------------------------------
PODCASTSNews Roundup: Live from the American Geophysical Union | Climate
Reflections: The SRM360 Podcast
News Roundup: Live from the American Geophysical Union
Climate Reflections: The SRM360 Podcast
30:46
<https://podcasts.apple.com/us/podcast/news-roundup-live-from-the-american-geophysical-union/id1779965690?i=1000680628040&uo=4>
"Host Pete Irvine is joined by SRM researchers Lili Xia, Chris Lennard, and
Tyler Felgenhauer for a live recording from the American Geophysical Union
conference in Washington D.C. They discuss the latest SRM news including:
the New York Times article on U.S. efforts to develop an early warning
system to detect SRM deployment; Florida senator Ileana Garcia's bill to
ban all "weather modification" activities; takeaways from the UNFCCC COP
related to SRM; the latest research on the impacts of SAI to human health;
the European Commission's chief scientific advisory recommendations on SRM;
and more!"
Simon Woods: Real Ice co-founder on the plan to re-freeze the Arctic | The
Sunday Session with Francesca Rudkin
"A UK-based startup is working on carrying out a bold plan to fix the
decline of sea ice in the Arctic.
Real Ice's ultimate plan is to re-freeze the Arctic by thickening ice to
slow down the damage caused by climate change.
Co-founder Simon Woods says this is their third winter of research - and
it's promising so far.
"We're chasing a moving target here - but at current levels, 1.2 meters of
ice should survive the summer, and that's what we want."
Geoengineering through solar radiation modification - a last chance option?
| TRACK CHANGES - climate change and sustainability interviews
Geoengineering through solar radiation modification - a last chance option?
TRACK CHANGES - climate change and sustainability interviews
56:31
<https://podcasts.apple.com/au/podcast/geoengineering-through-solar-radiation-modification/id1773158403?i=1000680911123&uo=4>
"There is no doubt that we have the means and the knowledge to rapidly
decarbonise, reach net zero, and become net negative. But success is not
guaranteed.
If we falter over the coming years, could geoengineering through solar
radiation modification be a last chance option? Might we reach the point
where we need to cool the planet, to give us a bit more breathing space
while we decarbonise? Is it possible, or is it too dangerous? Would it
undermine efforts to rapidly decarbonise? Would the benefits outweigh the
risks, taking into account the harm already being done due to global
heating?
How would the world decide whether to deploy solar radiation modification
(SRM), or even whether to conduct research? Who would make these decisions
and what would the guardrails be?
These questions are terrifying to contemplate. But so is the prospect of
temperature rise beyond 1.5 degrees.
Not surprisingly, there are deep divisions among the scientific community.
Some scientists - including high-profile climate scientist James Hansen -
consider our current situation is so dire that there should be a rigorous,
rapid scientific assessment of the feasibility and impacts of SRM
approaches.
There are other scientists who are resolutely opposed to SRM, and consider
it a dangerous distraction from a focus on decarbonisation and greenhouse
gas drawdown.
In this episode, I talk to Janos Pasztor who for seven years worked with
the Carnegie Climate Governance Initiative, which took neither a pro- or
anti- approach to SRM, instead focusing on governance issues around solar
radiation management.
He also talks about a new report on SRM issued by the EU Commission's top
scientific advisory body.
Janos's previous roles include UN Assistant Secretary General for Climate
Change and senior advisor on climate change to then UN Secretary-General
Ban Ki-Moon, in the lead-up to the 2015 Paris climate COP that led to the
Paris Agreement.
He has also held senior executive roles with environment group WWF
International, the UN Environment Programme (known as UNEP), and with the
secretariat to the UN Framework Convention on Climate Change."
Solar Geoengineering and Climate Justice | Climate on the Edge
Solar Geoengineering and Climate Justice
Climate on the Edge
1:11:31
<https://podcasts.apple.com/us/podcast/solar-geoengineering-and-climate-justice/id1766353019?i=1000680845176&uo=4>
"In this episode of Climate on the Edge, host Susan Su sits down with
Andrew Parker, founder and CEO of the Degrees Initiative, and a global
leader in the field of Solar Radiation Management (SRM). Degrees uniquely
focuses on SRM research for and by the Global South, and has pioneered
groundbreaking research grants and initiatives from South Africa to
Thailand."
------------------------------
YOUTUBE VIDEOSReducing Mortality in a Future with Extreme Heat: Part II |
SilverLining <https://www.youtube.com/watch?v=--sCGMNY_X0>
"During the 2024 American Geophysical Union Conference, SilverLining and
NYU Grossman School of Medicine, held "Reducing Mortality in a Future with
Extreme Heat," at the Kimpton Hotel Monaco in Washington, DC. This
conversation, titled "Research on Climate Intervention," was the second
panel of the event, focused on research, governance and equity
considerations for global-scale interventions in climate. The panelists
engaged on topics including a discussion of the research needed to evaluate
solar radiation modification (SRM) interventions, the practical and urgent
considerations for governance and global participation and what’s at stake
for younger generations."
Webinar: Stratospheric Aerosol Injection: A Pathway to Cooling the Planet |
Healthy Climate Initiative <https://www.youtube.com/watch?v=iDUVo1QF7yM>
"In this webinar, Dr. MacMartin will:
• Explain the science behind SAI
• Discuss its potential benefits and risks
• Highlight the role of informed preparation for society’s climate response"
Meer: Reflecting Sunlight to Cool the Planet | Healthy Climate Initiative
<https://www.youtube.com/watch?v=Lmzs_Bmqb7g>
"Abstract: As global temperatures rise, millions worldwide struggle with a
lack of affordable cooling solutions. MEER, an innovative NGO, has
developed low-cost reflectors that harness the power of sunlight reflection
to cool households, buildings, and potentially entire cities. This
groundbreaking approach offers a scalable pathway to cooling the planet and
addressing urgent climate challenges.
Join Dr. Ye Tao, Founder and Executive Director of MEER, as he presents the
science behind MEER reflectors, shares insights from pioneering projects in
India, and Sierra Leone, and outlines an inspiring vision for scaling these
transformative solutions worldwide."
Marine Cloud Brightening to Cool the Planet | Healthy Climate Initiative
<https://www.youtube.com/watch?v=qUtjaOlyZ0Y>
"Abstract: As the planet faces accelerating climate impacts, Marine Cloud
Brightening (MCB) emerges as a promising, cost-effective solution to
rapidly cool the Earth. By reflecting more sunlight back into space, MCB
has the potential to slow global temperature rise, refreeze polar ice, and
mitigate devastating weather events such as hurricanes, typhoons, droughts,
and floods.
Join Dr. Brian von Herzen, Executive Director of Climate Foundation and
Vice Chairman of HCI, as he explains the science behind MCB, and the
potential for cooling the planet, including its benefits and risks. Learn
about a groundbreaking intervention that could reshape our response to the
climate crisis. Don't miss this opportunity to engage with cutting-edge
climate solutions"
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*DEADLINES**Submit your recent research on Solar Radiation Management to
new ES: Atmospheres collection
<https://substack.com/redirect/af9e032d-e856-4ef4-a71c-2c359687818d?j=eyJ1IjoiMjJrMHl3In0.wQQsFypG52typ8FI2nhnJ8eUoUIIkdCkuhmzxNYKtgE>
| Deadline: 31 January 2025**Call for Proposals-Solar Radiation Management
<https://www.simonsfoundation.org/grant/solar-radiation-management/> |
Deadline to apply: 27 February 2025*(NEW) Call for Abstract—Arctic Repair
2025, Cambridge <https://www.arcticrepair2025.com/submissions> | Deadline
to submit abstract: 28 February 2025
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