Geoengineering against climate change: Many more risks than previously admitted
In view of the climate crisis, interest in technical manipulation of the Earth's atmosphere is growing. The risks are too often ignored, says a research team.
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The targeted release of aerosols into the atmosphere to slow down climate change is significantly more difficult and riskier than is often claimed. This has been determined by a US research group, which has now published its findings. As summarized by Columbia Climate School at the university of the same name in New York, proponents of such plans "dramatically" underestimate how difficult and complicated it would be to cool the climate specifically in this way. Without invoking catastrophic side effects. Should humanity ever attempt this, it would have to proceed with international coordination, which is unlikely given geopolitical realities.
Far too little focus on the risks
So-called "Stratospheric aerosol injection" (SAI) is a proposed measure for geoengineering, which is what large-scale technical interventions in the Earth's cycles are called, especially in the fight against climate change. Initially, the focus was primarily on sulfate-rich gases because they resemble volcanic clouds that have already caused measurable climate cooling, the group writes. Due to unwanted side effects – for example, on the monsoon in South Asia or on the protective ozone layer – interest in other substances has recently increased, primarily minerals such as calcium carbonate, zirconium oxide, and diamond. However, the focus has been on their optical properties, while other circumstances have been ignored.
As the team around Miranda Hack now explains, diamond is indeed well suited for the proposed task. But there simply isn't enough of the precious mineral. Others may be more readily available, but if one were to start releasing immense quantities of them into the atmosphere, supply chains would come under pressure and prices for the substances would quickly rise sharply. Minerals for which neither applies have other practical problems that would ensure they would not be of much help in the atmosphere. All of this would mean that such an approach would entail greater risks than the majority of previous proposals have acknowledged.
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As a result, the research group supports previously expressed warnings with the results of their simulations. Without international cooperation on a scale that is currently difficult to imagine, attempts to cool the climate with aerosols in the atmosphere would do more harm than good. If a country or a group were to act unilaterally, it could worsen droughts, disrupt the monsoon essential not only for India, but also alter storm patterns. It is not enough to simply "release five megatons of sulfur into the atmosphere"; it is immensely important where and when you do it, adds Faye McNeill, who was involved in the work. It was now published in the journal Scientific Reports.
(mho)
