Should we risk geoengineering to reverse climate change? 

After decades of efforts to curb global warming, scientists are now exploring ways to reverse climate change and potentially cool the planet. They are looking into geoengineering – strategies that manipulate Earth’s systems to mitigate climate effects. 

Geoengineering ideas include brightening clouds to reflect more sunlight, sinking lab-grown seaweed into the ocean to absorb carbon dioxide, or drilling holes into glaciers to slow sea level rise.

Complex questions surrounding geoengineering 

The University of Chicago has positioned itself at the forefront of this emerging field by recruiting physicist David Keith, who will lead a climate engineering program. 

Keith plans to build a team of 10 tenure-track faculty and several young researchers. He emphasizes the need for collaboration to tackle the complex questions surrounding geoengineering. 

“We cannot understand (geoengineering) with just a bunch of individual people working on this in an isolated way,” Keith explained. “We need to bring together a broad group of scholars and students to debate it in a much richer way.”

Solar radiation management 

For a long time, manipulating Earth’s systems was considered taboo, as many scientists viewed it as a distraction from reducing carbon emissions. Some even deemed it too dangerous to explore. 

The most controversial method is solar radiation management, which involves shooting aerosols into the atmosphere to reflect sunlight and cool the planet. Physicist Peter Irvine recently joined Keith’s team at UChicago to study this method. 

Solar geoengineering is expected to mimic the cooling effect of massive volcanic eruptions, such as the 1815 eruption of Mount Tambora in Indonesia. That eruption cooled global temperatures and dimmed sunlight for years. 

“Solar radiation management is the only (climate intervention) that could be deployed within a single presidential term,” Irvine said.

Geoengineering is becoming a necessary option

However, fears remain that promises of yet-to-be-developed technologies could be used by wealthy nations or fossil fuel companies to avoid reducing carbon emissions. 

With global emissions still rising and not being cut fast enough, some experts see geoengineering as a necessary option. 

As microbiologist Manon Duret, a recent recruit to the UChicago initiative, puts it, “it’s not going to happen. We’re not going to decarbonize the world so easily. We need to start looking at other options.”

Practical challenges to geoengineering

Duret will focus on practical challenges to geoengineering, such as material acquisition, logistics, and international regulations. 

Her husband, oceanographer B.B. Cael, will evaluate the risks, costs, and scalability of different geoengineering approaches. Both see geoengineering as a stopgap while society works on reducing emissions.

Buying time to address larger issues

Keith has been a leader in geoengineering research since the 1980s, launching one of the first companies to capture carbon dioxide from the air and leading Harvard University’s efforts in solar interventions. 

He argues that balancing emissions reduction with other societal priorities, such as equitable development, is essential. 

Keith believes that cooling the Earth could buy society time to address these larger issues. “The ethical thing to do is to cut emissions a little more slowly,” he said.

Risks of experimenting with the stratosphere 

Although solar geoengineering could reduce extreme weather events, it also carries significant risks. Irvine acknowledges that it might exacerbate droughts, increase acid rain, and thin the ozone layer. These unknowns could affect global food production and biodiversity.

Professor Liz Moyer, an atmospheric scientist at UChicago, shares concerns about experimenting with the stratosphere, where aerosols would be injected. 

The stratosphere has seen unpredictable events in recent years, and Moyer cautions that tampering with it without proper monitoring could be dangerous. 

“If you’re going to do experimental surgery and you haven’t thought about what kind of technology you would need to monitor the patient, then you’re not thinking about the problem carefully enough for me to trust you with my body,” she said.

Enormous burden on future generations

Solar geoengineering would require continuous intervention – shooting aerosols into the atmosphere every few years. 

Stopping this process could lead to rapid warming, known as “termination shock.” University of Oxford’s Raymond Pierrehumbert, a former UChicago professor, warns that this creates “an enormous burden on the future.”

Pierrehumbert is among more than 500 scientists calling for an international non-use agreement on solar geoengineering. He worries about the lack of a global governing body to oversee the responsible deployment of such technologies.

Reckless use by desperate nations 

On the other hand, Irvine believes that avoiding geoengineering research could lead to reckless use by desperate nations. 

“The more it’s suppressed, the greater the risk of a single nation or small group of nations pushing ahead independently in desperation,” he said.

While some countries like China have already experimented with altering weather patterns, most solar geoengineering research remains confined to computer models. 

However, real-world testing has been difficult to approve. Two planned experiments, one in California and another in Sweden, were recently canceled due to public opposition.

Risks and benefits of geoengineering 

Keith, who was involved in the Swedish project, remains committed to studying geoengineering to understand its risks and benefits. 

He argues that the public and politicians need rigorous research to make informed decisions about deploying such technologies. 

“It’s definitely not an elite club of scientists’ job to decide what the public gets to know or not,” he said.

Still, Pierrehumbert cautions that small-scale experiments might offer a false sense of security. Full-scale deployment would be needed to fully understand the long-term risks of geoengineering. 

“Scientists have a responsibility not to develop technology that could be threatening and destabilizing,” he explained.

Building an interdisciplinary team 

Despite these concerns, Moyer sees value in UChicago leading this conversation but stresses the importance of involving civil engineers, who are trained to account for risk in large-scale projects. 

Although Keith has plans to build an interdisciplinary team, so far, all hires have been in the geophysical sciences, and the university does not have a civil engineering department.

Facing the unknowns of climate change

What all scientists involved agree on is that the Earth is heating up rapidly, and it will take many years to cool it down, even if emissions are drastically reduced. 

“The climate is rapidly racing toward a state we’ve never seen before with all sorts of unknown consequences and known consequences that are going to be bad,” Irvine warned.

While some believe the only solution is to eliminate fossil fuel use as quickly as possible, others like Keith worry about a future where geoengineering is the last option, untested and misunderstood. 

Keith sees UChicago’s initiative as a way to ensure future generations are prepared. “In the end, this needs to be global, we need to build a field.”

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