Defined as the “deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change” (see Geoengineering the climate, the Royal Society), geoengineering is controversial. The mere fact of carrying out geoengineering research is largely debated within the scientific community, some considering it as a major distraction from the need to decarbonize the economy (i.e. there is no plan B) and a potential catalyst for geopolitical tensions, others considering geoengineering as an avenue to limit the damages of climate change and global warming on the environment and offering more time to reach net-zero.
Local climate engineering initiatives have already emerged around the world over the last few years, however (e.g. see Geoengineering Monitor Map, Heinrich Böll Foundation & ETC Group), and methods like cloud seeding have been used to enhance rain/snow falls in specific regions particularly hit by droughts.
With the historic climate events of the last few years, especially this year (2022), it seems clear that the temptation to use climate engineering techniques will increase, adding fuel on an already heated debate and potentially increasing pressure between countries.
Research on geoengineering regulation has started (e.g. The Regulation of Geoengineering, House of Commons (Science and Technology Committee), International Regulatory Framework for Geoengineering), but to the best of my knowledge, no international framework has already been established (please let me know if I miss something here).
While we could discuss on the usefulness of such framework in the first place, it is probably worthy to start drawing lines that shouldn’t be crossed internationally. Like some work has been done for the peaceful use of outer space (e.g. Space Law Treaties and Principles, UN OOSA), it seems important to establish the international basis for geoengineering, even if this framework solely prohibits the use of such techniques. Setting a framework is not so much to encourage and legitimate the use of geonegineering, but more to prevent its uncontrolled/unilateral use that could be detrimental and have adverse consequences globally. Methods for solar geoengneering have already been described and researched, so making sure these cannot be deployed without control seems important at this stage.
The Regulation of Geoengineering - Fifth Report states that “geoengineering techniques should be graded according to factors such as trans-boundary effect, the dispersal of potentially hazardous materials in the environment and the direct effect on ecosystems.”. Such grading system could serve as foundation for international regulation of geoengineering, and might allow to draft documents from first principles, regardless of specific methods. In fact, we could define a set of criterias used to grade geonegineering methods (e.g. have a scale of ”trans-boundaryness” - CDR would probably be low, cloud seeding would probably be moderate and stratospheric sulfur injection would probably be high, etc etc.). From that, we might then be able to define the boundaries of deployment (if any) of specific grades of geoengineering techniques. For example we could start by establishing “atmospheric EEZs” to regulate the exploitation of atmospheric resources (e.g. clouds, which can be harvested using cloud seeding to extract water that would be an input to a land process, like agriculture). Such approach may allow Grade 1 atmospheric geoengineering (e.g. CDR) from land level (0m) to, say, 1000m, might allow grade 2 atmospheric geoengineering (e.g. cloud seeding) from 500m to 1000m and prohibit any other type of geonegineering beyond these described use (i.e. the atmosphere above 1000m would be a common good that should be protected). Explicitly drawing the red lines by, e.g. defining the higher troposphere and higher layers as common protected good would allow to define state sanctions that could be enforced by an atmosphere equivalent of ITLOS or a new branch of the UNFCCC. Such sanctions would have the benefits of re-aligning incentives and forcing states to further regulate emitting sectors within their state boundaries (which is currently hard to do because Scope 3 emissions aren’t really subject to specific controls).
Of course, this simplistic example skims over many issues. Not only is the grading system employed here just a simplistic example, but such regulation would need to stay compatible with countries (and states)’ air sovereignty, and could, as we can see with EEZs, increase tensions in specific strategic areas to extend the EEZ (e.g. increased tension in the Hymalayas and other mountaneous regions to extend “atmospheric EEZ” etc.).