Climate engineering research is essential to a just transition and sustainable future

Climate engineering research is essential to a just transition and sustainable future
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The U.S. National Academies of Science, Engineering, and Medicine have recently recommended an expansive federal research effort into climate engineering techniques. These proposed interventions, like creating a layer of microscopic droplets in the upper atmosphere or brightening low clouds over the ocean, aim to reduce solar radiation arriving at Earth’s surface. While only a temporary means of addressing climate change, these strategies could prevent some of the worst effects of climate change while more permanent methods, like reducing greenhouse gas emissions, are ramped up.

Through the past few decades of research, mostly with climate models, we are starting to gain an understanding of the benefits and risks of climate engineering. Climate engineering cannot perfectly cancel the climate effects of greenhouse gases. For many climate aspects (like temperature, rainfall and sea ice), climate engineering does a good job of offsetting climate change in most places, but not all. There would also likely be many serious sociopolitical risks, such as geopolitical negotiations about ideal climates or transboundary harms (real or perceived) and compensation for them. These risks need to be carefully studied and weighed so that decision-makers can decide whether and how climate engineering should be used as part of the overall response to climate change. 

Despite researchers’ acknowledgment of these risks and the need to proceed cautiously, some have voiced total opposition to even conducting research on climate engineering. Climate engineering experts have been accused of looking for ways to prolong society’s use of fossil fuels or being guided by a “paternalistic form of humanitarianism” while aiming to suppress any other systemic solution to climate change. These arguments have undertones that climate engineering research and the pursuit of equitable systemic changes are mutually exclusive. We argue that such claims are wrong.


Keeping fossil fuels in the ground instead of burning them will prevent climate change from getting worse. Reversing climate change requires removing greenhouse gases from the atmosphere. Any honest framing of climate engineering needs to start with these physical science-based facts. However, a rapid transition to non-fossil fuel sources is unlikely to keep the world below the temperature targets negotiated under the Paris Agreement. A global temperature increase of 1.5 degrees Celsius could easily be reached by 2035, and serious, damaging climate change is already occurring prior to that threshold.

Some sectors, such as transportation, are difficult to decarbonize. In some cases, especially in developing countries, reliable, cheap electric power is more effective at preserving equity than green economy investments.

This already “baked in” warming increases risks. Glaciers are retreating, and with them, regular water supply for billions of people. Extinctions have been directly tied to climate change. Global agricultural productivity has slowed. The Antarctic ice sheet may be irreversibly collapsing, and the oceanic “conveyor belt” is slowing down.

These are not “punishments” by Mother Earth for our collective misbehavior, as some have framed them. They are the consequences of past and present political decisions, blended with misinformation campaigns and both corporate and governmental delays, which prevented the world from steering away from fossil fuels decades ago. The worst of these consequences are being felt by poorer, developing countries whose contributions to climate change have been minimal.

Climate engineering has been accused of being a “climate fix” or workaround that perpetuates addiction to fossil fuels and removes incentives to address the root causes of climate change. Such accusations often argue that the same technological thinking that is responsible for climate change cannot get us out of climate change. But greenhouse gas emission reductions will take time and require incredible political will. At the same time, planetary-scale greenhouse gas removal will be expensive, if it will even work at that scale. 


Climate engineering may be the only available option that could rapidly reduce the risks of climate change, and it will introduce novel risks as well. Opinions on whether and how it should be used may differ, and that’s a good thing. Concerns about research being a slippery slope to deployment or the specter of unintended consequences are legitimate and should be discussed. But shutting down the discourse dismisses voices from climate-vulnerable communities, including in developing countries and the long disenfranchised Global South, who want to have a say in the matter. There is much common ground and good will to be found between researchers and advocates for climate justice. Blanket dismissals of climate engineering research and the motives of those doing the research benefit no one. 

To start, we need to change the way climate engineering is often talked about: It is not a “solution” to climate change, a Plan B (a false dichotomy — should it only be used if mitigation fails?), nor a panic button in case of climate emergency. It is a possible tool to reduce suffering, particularly in the developing world. This tool needs evaluation. It does not “buy time” for an energy transition: the transition has to start now, regardless of whether climate engineering is used. No one thinks that climate engineering is an easy fix. It should be envisioned as a supreme assumption of responsibility: If climate change is indeed an existential crisis, then no option should be left off the table, and the benefits and risks of all possible methods of addressing climate change need to be understood.

Our hope is that society collectively realizes that moving as fast as possible toward reducing climate change is our best chance of preserving a liveable planet. If climate engineering could help, especially vulnerable communities, then outright dismissal may end up undermining a just transition to a sustainable world and ensuring more suffering than anybody deserves. 

Ben Kravitz is an assistant professor in the Department of Earth and Atmospheric Sciences at Indiana University. He is an expert on climate engineering research and is the co-founder and long-time chair of the Geoengineering Model Intercomparison Project (GeoMIP). His work has been featured in national and international reports, including the Fifth and Sixth Assessment Reports of the UN’s Intergovernmental Panel on Climate Change (IPCC) for which he was a contributing author, as well as testimony to Congress and the recent National Academies report on climate engineering.

Daniele Visioni is a postdoctoral research associate at the Sibley School of Mechanical and Aerospace Engineering at Cornell University. He has a Ph.D. in Atmospheric Physics and Chemistry from the University of L’Aquila in Italy. He is currently the co-chair of the Geoengineering Model Intercomparison Project (GeoMIP). Follow him on Twitter: @DanVisioni

Lisa H. Sideris is a professor in the Environmental Studies Program at the University of California Santa Barbara, after 16 years in the Department of Religious Studies at Indiana University. She is an expert in environmental ethics, the environmental humanities and the interface between science and religion. She is currently working on a book focusing on emerging technologies in areas such as de-extinction and astrobiology.

Douglas G. MacMartin is a senior research associate in Mechanical and Aerospace Engineering at Cornell University. Prior to joining Cornell, he spent 14 years at the California Institute of Technology. He leads Cornell’s effort on climate engineering research, and his work has been featured in numerous studies and reports. He has provided numerous briefings, including to UNEP, and he testified to Congress in 2017.