Solar Geoengineering: a Non-existent Non-solution

by L. Terzuolo

In this unusually warm early November, relay racing with the warmest summer on record, the reality of climate change has manifested itself before everyone's eyes. In this alarming context, it is natural to wish to wake up from this reality as if it were a nightmare, and there are indeed those who hope for quick and painless solutions to the existential threat we face. Among the alleged solutions is solar geoengineering, which goes beyond climate change mitigation and adaptation and embraces the idea of controlling the earth's climate.

Indeed, proponents of the development of this technology (which to date is purely theoretical) claim that extreme heat in the coming decades could be avoided by intercepting the solar radiation reaching the earth (hence the term Solar Radiation Management or SRM). This would be done by a layer of sulphate aerosols injected cyclically into the stratosphere with the function of shielding some of the sun's rays and thus lowering the planet's temperature (Biermann et al., 2022). The idea of SRM comes from the observation that large volcanic eruptions in the past, such as the Pinatubo eruption in 1991, have always caused rapid drops in Earth's temperature, and that this phenomenon can be artificially reproduced.

Why is solar geoengineering a false late with long-term effects. If we stopped using SRM once started, the warming effect of the accumulated CO2 would result in termination shock - a drastic and sudden and catastrophic rise in temperature. It is also illusory to think that solar geoengineering will buy us time for the ecological transition, and using it means putting ourselves in the position of having to continue forever. proponents, so the narrative around its use is biassed and downplays its critical issues.

This has serious consequences on policy, because portraying SRM as a 'solution' to climate change provides the rhetorical basis for fallacious and populist political slogans. Once the technology is developed, decisions about its use are unlikely to remain in the hands of scientists, and it could become a tool of economic-political interests aimed at continuing fossil fuel consumption instead of addressing the root cause of climate change.

Finally, SRM risks becoming the subject of huge geopolitical conflicts. As a planet-wide intervention with variable and uncertain regional effects (for example, a likely alteration of the Monsoon), which state or institution would have the right to decide how to use it? Given the heterogeneity of outcomes, what would happen if one country concluded it had achieved too much cooling and another pushed for more climate adjustments?

Why care about the debate if this technology is theoretical and undesirable?

It is important to understand the scien

It also negatively impacts scientific research because science must be falsifiable by nature. The scientific consensus around climate change and reports of the Intergovernmental Panel on Climate Change (IPCC) are based on the existing literature, so as to reflect the possible bias of the scientists researching it. If the publications on SRM are unanimous and positive, its conclusions become unfalsifiable and undebatable.

In light of these considerations, Solar geoengineering is a false simplistic solution to climate change, our most complex problem. If taken seriously, it will be no more than a distraction from our most essential task: decarbonizing the world economy to zero greenhouse gas emissions. It is therefore essential that the scientific community and society at large be aware in order to take an informed position.

With this in mind, the Utrecht-born network of scientists supporting the International Non-Use Agreement on Solar Geoengineering has launched a petition on change.org and published an open letter (which you can read on their website solargeoeng.org) to governments and the United Nations signed by more than 350 experts from over 50 countries to date. At Utrecht University, bachelor’s and master’s students are getting together to organise a Youth Working Group for the