In 1729, French engineer Bernard Forest de Bélidor broached the question of safety and reliability in engineering projects. The result of his questions is something called the precautionary principle, a legal and philosophical line of reasoning that weighs the potential costs and benefits of technological innovations. The precautionary principle has become standard in the world of scientific thinking, gaining much popularity in the 1970s. The application of the precautionary principle is even a legal requirement in the European Union.
Therefore, it is not a surprise that the PC(USA) utilizes the precautionary principle as a guide to think through our approach to scientific advancements and social responsibility. The 223rd General Assembly (GA) approved a report on the precautionary principle that explores how it can be used — for instance, in the evaluation of the PC(USA)’s stance on gene editing techniques in GMOs (Genetically Modified Organisms).
The GA223 precautionary principle report also explicitly provides a role for the Presbyterian Association on Science, Technology and the Christian Faith (PASTCF) to lead these types of conversations. That puts us squarely in a position of having responsibility in helping the denomination speak prophetically on scientific and technological issues and policy.
This article is intended as part of PASTCF’s response to this challenge. We feel moved to publicly express our concerns about solar geoengineering, a technology still under development that aims to diminish the amount of solar radiation reaching the earth’s surface and the lower atmosphere to reduce, and conceivably reverse, global warming.
There are two approaches to solar geoengineering: inserting reflective aerosols into the stratosphere or increasing the reflectivity of marine clouds. (Learn more here and here.) At this time research has mainly consisted of computer simulations, but plans are being made to start actual experiments in the atmosphere. This research has had the backing of both the Trump and the Biden administrations as well as funding support from benefactors like Bill Gates. The National Oceanic and Atmospheric Administration (NOAA) has been charged with managing the program and there is an active research team at Harvard. It also has some support among groups advocating measures to fight climate change.
However, there are serious questions about solar geoengineering that need to be properly addressed before starting work on developing the technology. Solar geoengineering is a perfect example of a technology that desperately needs precautionary principal considerations: think before you do anything — because once started it may be impossible to stop. Applying the precautionary principle highlights several serious concerns in five areas: physical side effects, longevity, political implications, inequity considerations, and international governance.
Physical side effects. The dispersion of aerosols in the stratosphere is nothing new; volcanoes have been doing it for several billion years. However, the side effects have not always been beneficial or even neutral, and, before we start doing this ourselves, we first need to understand what the impact of the large-scale injection of specific aerosols would be on human and other populations. In addition, if this is to be done on a scale where it would make a difference, there are serious questions about how this is going to affect atmospheric and oceanic circulations.
Longevity. The effects will not last forever, much like the effects of major volcanic eruptions do not last forever. Solar geoengineering is a band-aid; if it is to have a lasting impact on global warming, it needs to be continually refreshed. In that sense the technology has all the characteristics of an addictive drug — we would have to keep using it to receive the benefits which would cover our environmentally harmful practices and leave our planet worse off in the long run. People involved in solar geoengineering argue that the technology can be used as a “Plan B” in case we cannot reduce humanity’s carbon footprint in time. Yet if we were to start and stop the solar geoengineering process, the measures required to contain climate change will need to be much more draconian than what we currently have.
Politics. Once this technology is tested and available, it would be too easy to apply a solar geoengineering band-aid to the problem of climate change. And it would be a tempting band-aid for politicians looking for an easy, cheap solution without considering the long-term impact. Additionally, companies in the geoengineering field, seeing the potential for huge earnings, will pull out all the lobbying stops.
Inequities. We know that the effects of coal-burning plants can be felt downwind over long distances. Solar geoengineering’s effects will be felt over an even larger area. Much of the aerosols will likely make their way to lower latitudes — which is the part of the earth where many poorer countries reside. Yet, again, it will be the poor who will pay the highest price.
International governance. No country can release aerosols in the stratosphere overhead and make it only shield that country’s patch on the surface. The particles, like carbon dioxide, know no boundaries, so no country should embark on a solar geoengineering endeavor until an international system of governance is in place — one that gives special attention to the most affected countries.
In the February issue of Sci†Tech, the PASTCF newsletter, I applied the precautionary principle to express my concern about solar geoengineering, which I hold to be far more threatening than GMOs. I had hoped that Biden’s new administration might shelve the solar geoengineering “solution,” but the reverse appears to be true.
It is nearly impossible to prevent a developed technology from being used when it promises to provide cover for politicians faced with hard choices and when it is a source of significant profits for the industry involved. It is simply too hard to put the genie back into the bottle once it is out. We need to make sure all aspects have been thought through and resolved before actual work is started. Therefore, it is critical to apply the precautionary principle to the development of solar geoengineering technologies. And the PC(USA) should say so.
Arnold Rots is president of the Presbyterian Association on Science, Technology and the Christian Faith. He is a ruling elder, a retired astrophysicist and lives in Waltham, Mass.
