17 March 2023

The climate crisis has led some experts to argue that more risky measures now have to be investigated. One such measure would be regulating solar radiation to cool Earth. But how do those developing this controversial technology reason when it comes to uncertainty? This is the subject of a new research project at Linköping University.

The sun and a thermometer showing high temperatures.
The climate crisis forces us to consider desperate measurs, some scientists argue. batuhan toker
As early as in 2006, environmental scientist and Nobel laureate Paul Crutzen argued that the time had come to consider risky methods to counter climate change. He was referring to attempts to regulate solar radiation, a method known as solar radiation management, SRM.

But this is a controversial idea. A small pilot project in Sweden in 2021 had to be closed down at the planning stage, as attempting to manipulate the climate can actually have unforeseen consequences.

SRM is being taken increasingly seriously

Anders Hansson.Anders Hansson. Photo credit Anna Nilsen So far, SRM exists only as a thought experiment and in data models. But it is now being discussed more seriously, and the UN climate panel, IPCC, also analyses the methods in its reports, according to Anders Hansson, senior associate professor at the Environmental Change platform of the Department of Thematic Studies at Linköping University.

He is in charge of a research project that for the next few years will be looking at the leading SRM modelling programme; the Geoengineering Model Intercomparison Project. The Linköping researchers will study how knowledge about the regulation of solar radiation is created, how the researchers handle the deep uncertainty surrounding this technology, the role of technology in society and how they see their own role.

The Linköping team will also study the IPCC’s stance on this controversial technology. The project has received SEK five million in funding from the Swedish Energy Agency, and its ambition is to inform the rest of Swedish society about the complex issue in an easily comprehensible manner.

“This has an important democratic function, as the use of SRM may impact all people and all vegetation on Earth,” says Anders Hansson.

Consequences are difficult to foresee

One method considered is releasing sulphur particles into the atmosphere to reduce solar radiation, similarly to what happens in volcanic eruptions. The problem is that it is difficult, if not impossible, to foresee the consequences of this. These are some problems that could arise:

• Continents could be impacted differently. South-east Asian monsoon patterns, for instance, could be disturbed, while Europe could get a more comfortable climate.
• SRM could reduce motivation to do something about the actual problem, i.e., greenhouse gas emissions, and so, ocean acidification etc. would continue.
• Less solar power and a different-looking sky.
• The system would possibly have to be maintained without interruption for hundreds of years, which requires political stability.
• The SRM technology could have military applications.

“Many informed researchers believe that the only way to gain enough knowledge is through full-scale testing. The dilemma is that this could mean putting our entire planet through a risky experiment,” says Anders Hansson.

He is running the research project together with Mathias Fridahl and Daniel Andersson at the Environmental Change platform of the Department of Thematic Studies.

Translation by Anneli Mosell

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