Why the new “Letter of Support for Solar Geoengineering Research” is misguided

The normalization of solar geoengineering as part of climate policy is progressing, with growing numbers of journal articles by geoengineering research advocates, editorial pushing by some science journals, and supportive actions by a few science networks in the United States. However, the opposition to solar geoengineering in global academia is growing as well, and more rapidly, with now over 410 scholars who have signed an Open Letter calling for an “International Non-Use Agreement on Solar Geoengineering”.

In a new development, a group of physical and biological scientists – 62% of them from the United States – have published on 27 February 2023 a “Letter of support for research on atmospheric aerosols and their potential to increase the reflection of sunlight from the atmosphere to address climate risk”.

This letter is welcome inasmuch as the signatories do not call for solar geoengineering deployment. We also all agree that the climate crisis is severe, that drastic cuts in emissions are needed, and that science needs to play an important role. However, in many other aspects, this “Letter of Support for Research” is highly problematic. Here we lay out seven points of critique:

First, the “Letter of Support for Research” is devoid of any considerations of the social and political implications of research into planetary-scale geoengineering. Wherever this letter turns to questions of potential deployment, the authors use the passive voice or refer to unspecified “informed decision-making”. The authors talk for instance vaguely about “outcomes” that “might be optimized if multiple techniques were used in combination”, implicitly assuming a global political actor who would use robust science to implement a consistent and coherent geoengineering scheme at planetary scale over several generations. Such an actor, however, does not exist. Instead, solar geoengineering is likely to lead to dangerous geopolitical conflicts, with nations fiercely fighting over control of the “global thermostat”. This is likely to be accompanied by the further disempowerment of smaller countries in the Global South that will lack access to, or control over, planetary-scale interventions into the earth’s climate, undertaken by the most powerful actors best placed to develop and deploy these technologies. The passing reference by this group of natural scientists to the need for “international cooperative governance” denies the reality that a model for international decision-making to manage a multi-generational deliberate intervention into the earth’s climate system, in a democratic, fair and effective manner, does not exist.

Second, the “Letter of Support for Research” opens the door wide to the rapid deterioration of existing climate policies, which would be delayed and derailed. Powerful actors that profit from the production, sale and consumption of fossil fuels are likely to use the speculative hope of solar geoengineering to lobby hard for a weakening of current mitigation policies, arguing that the costs of future mitigation could be reduced by adding cheap geoengineering to the mix. Such instances of “mitigation deterrence” have been observed for carbon sequestration and removal; they will skyrocket once solar geoengineering becomes further normalized in the climate policy discourse. 

Third, the signatories to the “Letter of Support for Research” place themselves outside the consensus view of the Intergovernmental Panel on Climate Change (IPCC). The recent IPCC reports, based on a careful review of the existing state of the science, show various pathways that would limit global warming to 1.5-2.0 degrees Celsius. The last IPCC Working Group III report does not even mention solar geoengineering in its summary for policymakers. Yes, the IPCC also states that these pathways require drastic emission cuts, but these cuts are feasible and all efforts in the next decade need to ensure that they materialize. The “Letter of Support for Research” instead simply declares such policy changes as unlikely, calling into question any chance of success for policymakers, civil society and the millions of citizens around the world who support transformative change.

Fourth, the signatories to the “Letter of Support for Research” show a dangerous ambiguity over the use of solar geoengineering in commercial offsetting schemes, such as the claims by the “Make Sunsets” company to have conducted stratospheric aerosol injections that would offset one tonne of carbon dioxide emissions for a contribution of 10 US dollars. While the “Letter of Support for Research” does not support such schemes at present, its authors present this reservation as conditional, writing that the “state of scientific knowledge about SRM [solar radiation management] is also currently insufficient for it to be included as part of a climate credit system or other commercial offering.” The implication is thus that the inclusion of solar geoengineering into a climate credit system or commercial offset programme might well be possible once the science has sufficiently progressed. The signatories do add some caution about geoengineering in an “open market system of credits and independent actors”, but this does not preclude the inclusion of geoengineering in misguided country-run offset schemes. For example, any country could claim to continue selling or consuming massive quantities of gas and oil by offsetting this through a future national solar geoengineering programme of their own making – something that would be fully within the logic and likelihood of this letter.

Fifth, the signatories to the “Letter of Support for Research” show no concern for the geopolitical and global justice implications of their text. The letter mentions the “Global South” only in its last sentence, as a place in need of support for research, without acknowledging the utmost need of the Global South for effective political control over any attempts at hacking the global climate by elite actors in the Global North. Again, the signatories of this letter seem oblivious of the political implications of such research, which advances nothing less than knowledge over intentional massive interventions into the global climate system – knowledge that could be used by any public or private actor, even unilaterally, without any global public control or consent. This lack of geopolitical concern is a consequence of an idealistic, technocratic imaginary of a global system that can be “steered” by benevolent global managers with support from omniscient experts and climatologists.

Sixth, the technocratic worldview of the letter becomes evident also in their claim that research on planetary-scale geoengineering “must be undertaken independently, so that research findings and assessments are protected from political influence, business interests, and public pressure”. Essentially, the signatories seem to prefer to conduct their research, and govern their programmes, without governments having oversight over their experiments; and they seem to want to keep the public out, framing the democratic voice of citizens as “public pressure” that must be avoided. 

Seventh, the letter endorses “small scale” field experiments, without addressing whether such experiments have a chance to answer any of the most significant questions regarding the response of climate to large-scale deployment, or whether such experiments would inadvertently or deliberately develop technologies that would be used for deployment by rogue actors outside the control of scientists doing the research, however well-intentioned they may be. Also, in assuming that further research will determine the role that solar geoengineering might or might not play in addressing the climate crisis, the letter ignores already-known science that makes the likelihood of useful and non-hazardous deployment scenarios vanishingly small. In particular, in view of the long-term persistence of carbon dioxide in the atmosphere, if solar geoengineering comes to be relied upon, it must be sustained over the lifetime of many generations. An abrupt termination would lead to a rapid warming known as “termination shock”, which could well, through rapid warming, make it even more likely to trigger the “tipping points” the letter is concerned with. No amount of research is going to make that problem disappear.

In sum, a geoengineered future is neither inevitable nor necessary. An end to oil, gas and coal is possible, and easier to achieve than managing the planet through continuous stratospheric aerosol injections over several generations. The geoengineering fallacy must not become a “new normal”. What is needed is an international consensus that solar geoengineering is not our future. This requires an International Non-Use Agreement on Solar Geoengineering that stops any attempt at normalizing planetary-scale intervention techniques as part of the current climate policy mix. Such a non-use agreement would need to commit governments not to deploy solar geoengineering technologies and not to support their development; it would require governments not to grant patents to private actors for such technologies, and not to allow dangerous outdoor experiments with such technologies. Over 410 academics from 61 countries have signed since January 2022 an open call for such an International Non-Use Agreement on Solar Geoengineering; numerous civil society organizations have endorsed this initiative. 

Scientific research is vital for human progress, and all 410 signatories calling for this non-use agreement are researchers, devoting their life to scientific work and study. But research is not innocent. Scientists have a responsibility for the political implications and geopolitical consequences of their findings. Planetary climate interventions are not a mere research idea. They bring huge risks for humanity, especially the global poor. Global regulation is thus needed: an International Non-Use Agreement on Solar Geoengineering, with clear controls over technology development, is the need of the hour.

This blog post is based on discussions within the coordinating group of the initiative for an International Non-Use Agreement on Solar Geoengineering and has been written by Frank Biermann with input from Wolfgang Cramer, Aarti Gupta, Raymond Pierrehumbert, Jennie Stephens, and Stacy VanDeveer. All specific views expressed here do not necessarily represent the views of all of the over 410 signatories of the open letter calling for this non-use agreement.

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