Could Geoengineering Really Combat Climate Change?

Governments worldwide are searching for ways to decarbonise and tackle climate change, while many continue to rely heavily on fossil fuels for their energy. This has led several countries to explore the potential for geoengineering to combat climate change without relying entirely on the gradual shift away from fossil fuels to renewable alternatives. However, while some experiments are showing promise, it is still unclear how effective many geoengineering activities are, and some are concerned about the potential secondary effects of these projects.

Geoengineering refers to deliberate, large-scale interventions in Earth's natural systems to counteract climate change or mitigate its effects. These interventions are broadly divided into two groups, carbon dioxide removal (CDR) and solar radiation management (SRM). Carbon capture and storage (CCS) operations are already in place in several countries around the globe, supported by the recent rise in investment in CCS technology by oil and gas companies looking to decarbonise operations. Other CDR methods include ocean geoengineering, afforestation, and enhanced rock weathering.

The second type of intervention, SRM, is designed to reflect a portion of the sun's energy away from Earth to reduce the amount of solar heat that can be trapped in the atmosphere. Current methods include injecting aerosols into the stratosphere, ‘brightening’ clouds, and even placing reflective surfaces in space to reduce the amount of sunlight reaching Earth. This method is far more controversial than CDR as there is little understanding of the potential secondary effects and because of the lack of sectoral regulation.

In April, the U.K. announced plans to conduct small-scale outdoor geoengineering experiments as part of a $66.7 million government-funded programme. This and another $14.8 million project will make the U.K. one of the world’s largest investors in geoengineering research. 

The Advanced Research and Invention Agency (Aria), which is leading the research programme, has assured the public that no toxic substances will be released during the experiment and that an environmental impact assessment will be published ahead of any SRM activities. Further details are expected to be published by Aria in the coming weeks. 

The head of the Aria programme, Mark Symes, explained, “The uncomfortable truth is that our current warming trajectory makes a number of such tipping points distinctly possible over the next century… This has driven increased interest in approaches that might actively cool the world in a short timeframe in order to avoid those tipping points.” 

Symes believes that a wide range of methods will be needed to tackle climate change, not only decarbonisation. “Having spoken to hundreds of researchers, we reached the conclusion that a critical missing part of our understanding was real-world, physical data. These would show us whether any of these potential approaches would actually work and what their effects might be. Modelling and indoor studies are essential as prerequisites but can only tell us so much.”

However, many environmentalists and scientists are concerned about the potential impact of conducting SRM experiments. Some senior scientists have called the programme a “dangerous distraction” from cutting emissions and suggest that funding would be better spent on efforts supporting a net-zero carbon emissions outcome. Because of the controversial nature of geoengineering, several previous outdoor experiments have been cancelled due to opposition. Many worry that SRM may have serious unintended consequences, such as shifting rains vital to food production. 

A $13.3 million geoengineering research programme was announced by the U.K.’s National Environment Research Council (NERC) in early April, which aims to explore the impact of solar geoengineering interventions. It will use computer modelling, existing data, and natural analogues to assess the potential impact of SRM. 

Due to the lack of understanding about the possible repercussions of SRM activities, several leading figures have called for the introduction of international regulations on such projects. In 2023, the Climate Overshoot Commission published a report that said while countries should conduct greater research on SRM to understand it better, governments should not conduct SRM activities because of the dangers involved in tinkering with the global climate in ways that are not yet well understood.

At the United Nations Environment Assembly, held in Nairobi in February 2024, some governments led by the African Group of countries proposed the banning of SRM activities. Meanwhile, other world powers, led by Switzerland, suggested establishing an expert panel to research the nascent approach. No consensus was reached, meaning that countries were able to freely conduct SRM activities. 

Little is known about the efficacy and potential secondary effects of SRM geoengineering activities. While some are hopeful that SRM activities could help tackle climate change, others are worried about the potential unintended consequences of these types of experiments. Meanwhile, many scientists suggest that funding SRM operations is merely a distraction from tackling the main cause of climate change – the excess greenhouse gas emissions that have been driven up by the world’s overreliance on fossil fuels.