The European Commission's scientific advisers have called for a moratorium on large-scale solar geoengineering experiments across the EU, citing insufficient scientific evidence to support the technology's effectiveness in combating climate change. The Group of Chief Scientific Advisors (GCSA) and the European Group on Ethics in Science and New Technologies (EGE) published their opinions, which highlight the uncertainties and potential risks associated with solar geoengineering.

Solar geoengineering involves artificially cooling the planet by reflecting sunlight back into space, primarily through the use of reflective particles in the atmosphere or brightening clouds. Proponents argue that this technology can help mitigate the effects of climate change, but small-scale experiments have sparked controversy and concerns about unintended consequences.

The GCSA's opinion emphasizes that solar geoengineering merely addresses the symptoms of climate change, rather than its root causes. The technology does not reduce greenhouse gas emissions, nor does it address other critical consequences such as ocean acidification. Furthermore, solar geoengineering could lead to unforeseen problems, including changes in rainfall patterns, impacts on food production, and disruptions to solar energy generation.

One of the most prominent methods of solar geoengineering involves mimicking volcanic eruptions by releasing sulfur dioxide into the stratosphere, producing a reflective haze. However, this approach has its own set of risks, including the potential to irritate human lungs, cause acid rain, and damage the Antarctic ozone hole. A US-based startup sparked controversy in 2022 by releasing sulfur dioxide-filled weather balloons in Mexico, prompting the country to ban solar geoengineering experiments.

The European Commission's scientific advisers recommend that the EU oppose the use of "cooling credits" from solar geoengineering, which could be used to offset carbon emissions. They also advocate for a more explicit EU-wide moratorium on large-scale geoengineering experiments and suggest setting the stage for a new international treaty on solar geoengineering.

While some cautious efforts have been made to fund legitimate research into solar geoengineering, the European Commission's scientific advisers emphasize that such research must be rigorous, ethical, and consider the potential range of direct and indirect effects. Ekaterina Zaharieva, commissioner for startups, research, and innovation, noted that "these technologies do show some promise, but they are far from mature."

The call for a moratorium on solar geoengineering experiments comes as lawmakers face pressure to establish stronger international rules governing the technology. The United Nations Convention on Biological Diversity adopted restrictions on large-scale geoengineering in 2010, but exemptions for small-scale experiments have created a regulatory loophole. The European Commission's scientific advisers recommend that the EU advocate against deploying solar geoengineering technologies globally for the "foreseeable future."

As the debate surrounding solar geoengineering continues, the European Commission's scientific advisers have sent a clear message: more research is needed to fully understand the implications of this technology, and a moratorium on large-scale experiments is necessary to prevent potential harm to the environment.