A systems approach begins with limiting greenhouse gas emissions and adapting to unavoidable climate disruptions, while researching the feasibility and governability of geoengineering.
According to the Intergovernmental Panel on Climate Change’s latest report, issued in 2014, any plausible path for reducing global greenhouse gas emissions that would keep the Earth from warming by more than 2 degrees Centigrade will require direct interventions to modify the atmosphere—that is, geoengineering. This conclusion obviously applies even more starkly to the aspirational goal of limiting warming to 1.5 degrees or less that was adopted at the 2015 United Nations climate conference in Paris. These targets indicate that we should be prepared for a future where deployment of technologies to intentionally modify the global climate for human benefit will be contemplated, and thus in turn that we need to know more, and soon, about if and how such modifications might work.
Calls for research on geoengineering have consequently been finding their way into reports from high-level scientific and policy organizations, including the US National Academy of Sciences, the UK Royal Society, and the Bipartisan Policy Center. For the first time, the US Global Change Research Program’s strategic plan, currently in review, calls for research on geoengineering and highlights specific issues for research.
Since the Nobel Prize-winning atmospheric chemist Paul Crutzen wrote his famous article in 2006 pointing to the possibility that humans could deliberately cool a warming Earth, scientists have focused on two possible classes of geoengineering technologies. Solar radiation management (SRM) technologies either reflect some of the radiation coming from the sun—for example, with particles injected in the stratosphere or clouds—or remove radiation-trapping barriers such as cirrus clouds to allow more radiation to leave the Earth. Carbon dioxide removal (CDR) technologies remove carbon dioxide and other greenhouse gases from the atmosphere to set the clock back on climate change.
Unlike mitigation and adaptation, which can be pursued at independent national and even local levels, the character of geoengineering intervention—whether SRM or CDR—is fundamentally strategic at the global level. Climate intervention would require developing the elements of a strategy: setting a global goal for the intervention, choosing specific actions, and developing methods for monitoring the results and mechanisms for changing course as more information becomes available.
These ideas—especially for SRM, which might be relatively inexpensive and fast-acting—remain controversial. One common ethical concern about geoengineering, known as the “moral hazard” problem, could result in people thinking that geoengineering can relieve us from the need to mitigate emissions by decarbonizing the global energy system. In truth, SRM-type technologies could not safely keep up with an ever-growing concentration of greenhouse gasses in the atmosphere. Without mitigation, the amount of radiation imbalance would continue to grow, so the amount of intervention required to keep temperatures below a specific limit would also grow. But SRM does not perfectly cancel the impacts of continued emissions. Attempting to counteract an ever-increasing greenhouse gas effect through commensurate efforts to artificially deflect solar radiation will lead to larger and more dangerous departures from known climate states. Thus, mitigation constitutes a prerequisite for practical SRM. Geoengineering should never be thought of as an independent technology.
The climate intervention endeavor should be part—and only part—of a symphony of actions harmonized for managing the global environment. The most important strategy remains eliminating greenhouse gas emissions. Stopping emissions does not equate to adding up how much solar power has been added to the grid, and it certainly does not equate to how much nuclear power is taken off the grid. It means stopping emissions. Adaptation is crucial, as well. The flooding, droughts, ecological damage, and fires exacerbated by climate change will have to promote increased attention to creating resilience, resisting the changes, or retreating from problematic regions. Climate engineering may augment these foundational instruments; it will not replace them.
The research community largely knows that geoengineering as currently defined makes no sense without a vigorous attempt to mitigate greenhouse gases, and that adaptation will be necessary as well. However, researchers may have—likely unwittingly—played into the slippery slope concern by differentiating different types of geoengineering according to how they perceive the governance issues. For example, the recent National Academy of Sciences report on geoengineering was separated into a report on SRM and another on CDR because researchers see these as distinct technologies having distinct governance requirements. Although a split in governance may serve the interests of science projects, it forfeits an opportunity to think about a holistic climate strategy and may not be in the best interests of society. Keeping research on geoengineering firmly in a comprehensive context, including mitigation, adaptation, CDR, and SRM, should help protect society from the moral hazard and promote strategic thinking.
The latest set of agreements in Paris made a major advance by establishing the goal of controlling temperature. But the world is far from agreeing on the means to reach that goal. In fact, each country will propose its own means, with no guarantee that a successful global approach will emerge. But contemplation of climate engineering invites consideration of an overall strategy on climate. For example, if mitigation proceeds, but not fast enough to avoid dangerous effects of warming, SRM may help to cut off the peak of the problem. However, wise deployment of SRM would have to be predicated on an end game for stopping deployment. If the time comes when we have finally stopped emitting excessive amounts of greenhouse gases, but the persistent atmospheric concentrations of carbon dioxide remain too high for comfort, then we could deploy SRM only until a long, slow effort to lower atmospheric concentrations using CDR technologies makes it safe to stop SRM.
Research and governance
But we don’t yet know if geoengineering technologies will work. To even begin to take seriously any such strategic approach for addressing climate change, we will therefore have to do research. And given the high stakes and controversial nature of geoengineering, research programs will have to be accompanied by a well-structured governance approach to ensure that policymakers and the public alike have confidence in the science and its implications for action. To push the symphonic metaphor perhaps a bit too far, effective research governance will be required to ensure that the instruments of atmospheric management are in tune. Such governance should be guided by a small number of principles.
Given the high stakes and controversial nature of geoengineering, research programs will have to be accompanied by a well-structured governance approach.
International collaboration focused on monitoring and results-sharing can provide a good path forward. In the past, international collaborative research has helped to establish international policy on difficult subjects. For example, international cooperative research demonstrated that geophysicists could detect any nuclear weapons tests conducted anywhere, anytime, and this capacity in turn enabled ratification of the nuclear test ban treaty. Similarly, international cooperative research on detection and attribution of deliberate climate interventions would be a strong starting place for building trust into international discussions of geoengineering options.
The Intergovernmental Panel on Climate Change has been encouraging international collaboration through model inter-comparison projects focused on SRM, and there is additional important work to do using numerical models and thought experiments. Collaboration could also come about if a few countries start their own research programs and then work together. Researchers have already proposed small experiments to illuminate and delimit physical, chemical, and biological processes that underlie model assumptions. Individual nations could fund these experiments, but early international collaboration would point toward the eventual goal of internationalized research and commonly held results.
Starting research governance simultaneously with outdoor research allows governance skill to grow along with scientific knowledge and will help to ensure that governance for more difficult problems is not left until the last minute.
The early experiments should start small and be limited to those that present negligible risk of perturbing the climate. Any larger-scale or more risky experiments in geoengineering should be considered only later, if at all.
Coordinate scientific and governance learning. If at some time in the future there were significant scientific gains to be made with experiments that crossed national boundaries or posed some risk, even if relatively small, imagine how difficult it would be to govern these if none of the basic elements of governance had been assembled and exercised beforehand. Starting research governance simultaneously with outdoor research allows governance skill to grow along with scientific knowledge and will help to ensure that governance for more difficult problems is not left until the last minute.
External and independent advisory groups can help scientists to articulate clearly the key questions they are trying to answer and facilitate deliberation with the public. For example, scientists might be trying to answer the question “Is this technology effective?” or “Is this technology safe?” The purpose of the proposed experiment might be to answer the question “How does a specific mechanism that affects efficacy or safety work?” Citizens and policymakers might agree (or not) that they would like the answers to these questions, but they might also have their own questions. A scientist may want to determine how small particles coalesce into larger ones. A citizen may want to know which chemicals would reach breathable air. Dialogue can help to focus and articulate research questions and help scientists to better understand and thus explain (or modify) their own priorities. This may sound easy, but in practice it takes time and attention. Even if an engaged public agrees with the research questions, they may challenge the need for the proposed experiment to answer them.
Public and policymaker engagement in setting the goals for research can be one of the most important interfaces between science and society, even in early research, especially if these goals can be articulated in terms of questions people have. For example, just as nuclear test ban treaties were enabled by answering the question “Can nuclear tests be detected?” policymakers will likely have similar questions about detection and attribution for geoengineering research. If we decide to deploy an SRM technology and a country subsequently experiences drought, can scientists say how much the geoengineering technology had to do with that drought? If the answer is “yes,” the policy discussion will be quite different than if the answer is “no”—or, perhaps most likely, “we’re not sure.” The answer will also have large implications for a decision about whether to deploy and if that choice is made, what forms of governance should apply to that deployment.
Mission-driven research should inspire creativity in intervention concepts, select the best ideas, and then systematically determine their effectiveness, advisability, and practicality in the context of mitigation and adaptation.
Assure the quality and reliability of the research. No matter how long we work on these problems, we will never have the ability to precisely engineer an intervention. The models developed to explore possible responses to intervention cannot be validated at full Earth scale in double-blind tests. We can only hope and expect that research will increase confidence that we can (or cannot) move the Earth system in a beneficial direction. Some confidence could accrue if, over time, researchers are increasingly able to predict the results of their experiments a priori. The discipline of prediction and comparison of the prediction with results should be part of all geoengineering research. Twenty-twenty hindsight has much less impact on confidence-building than a priori prediction and ex post facto comparison of predictions and actual outcomes.
The principle of transparency comes up often as important for geoengineering research. But transparency involves much more than revealing the experimental plan and releasing data. Meaningful transparency has to enable dialogue and deliberation, so it must include revealing the intent of experiments: What is the experiment trying to achieve and why is the experiment the best way to get there? What is the quality of the information forming the basis of the experiment? How did the actual results differ from the hypotheses? What was learned from the differences and what could be done next and why? An advisory group can help guide researchers through the transparency process and react to the reporting.
The normal process of scientific peer review may do well to ensure the reliability and veracity of individual research papers, but if any geoengineering concepts start to undergo serious research, review and assessment of the work will need to recognize that engineering the climate involves more than stand-alone research papers. The completeness of the study and accuracy of the assessments might be addressed by funding teams of researchers whose job it is to find out what might be missing or wrong.
Organize research around the mission, not the scientific opportunities. Geoengineering is fundamentally engineering—that is, a solution designed to solve a problem—and in this case the problem involves a system of many interrelated processes and issues. An engineering project, particularly one of this magnitude and complexity, requires a systems approach. Research should both define the critical elements of the system and investigate the total system response to intervention. Haphazard investigation driven by scientific curiosity is unlikely to take up all the elements of a systems approach and may even be unethical given the stakes involved in climate intervention.
Mission-driven research should inspire creativity in intervention concepts, select the best ideas, and then systematically determine their effectiveness, advisability, and practicality in the context of mitigation and adaptation. Design of a mission-driven climate engineering research program provides practice in skills critical for managing any possible future deployment of such technology. Re-invention of mission-driven research for geoengineering should learn from previous shortcomings, such as narrow control and poor communication, reckless disregard for collateral damage, and lack of public engagement.
Sweden’s nuclear waste program presents an excellent example of successful mission-driven research on a controversial subject done with strong international collaboration and public interaction. The program linked technical and managerial task groups with ideas about project requirements and strategies, and engaged communities that were plausible site candidates. A “safety case” described simply what the requirements for a site would be and why scientists thought a site that met these requirements would be safe. Only sites that met the criteria were selected for further characterization, and that proceeded only if municipalities agreed. The safety case was updated regularly so that it was easy to see that confidence in the concept was increasing. Repeated interactions with citizens in affected communities led to project acceptance. Sweden now has a licensed nuclear-waste repository in a community that asked for it. Many of these same concepts would work for mission-driven geoengineering research.
One important distinction for geoengineering research is that the mission should not be to deploy a geoengineering concept. The goal for climate intervention research must be to understand the potential efficacy, advisability, and practicality of various concepts in the context of mitigation and adaptation. This means that concepts should always be evaluated relative to plans and projections about mitigation and climate effects. Importantly, this also means that a research institution investigating a specific concept would fulfill its mission if it found that the concept was a bad idea. We do not currently reward scientists or research institutions for identifying bad ideas. The reward structure for institutions conducting mission-driven research must reflect the societal benefit desired from the program, including eliminating an inadvisable concept.
The extraordinary difficulty of moving the global economy to eliminate greenhouse gas emissions is beginning to force serious attention on geoengineering. This attention in turn compels us to think about climate change in ways that are both strategic and global. It allows us to imagine how a symphony of harmonized actions might be necessary for assuring the long-term well-being of humanity. We might, for example, eliminate emissions as fast as we can, adapt as well as we can, use solar radiation interventions for a limited period to buy more time for mitigation while preventing climate changes that create insurmountable challenges, and then find ways to remove the troublesome gases from the atmosphere and conduct the Earth back to a more stable, livable climate so that radiation interventions can be stopped.
Strategic thinking at this level creates a social imperative to begin learning more about geoengineering and to govern the necessary research in ways that assure the confidence of the public and policymakers. Thus, even if humanity has the good fortune never to have to deploy geoengineering, the contemplation of these technologies is beginning to provide us with an opportunity to come to terms more holistically with the nature of the challenge that we face.
Jane C. S. Long, now retired, was formerly associate director for energy and environment at Lawrence Livermore National Laboratory and dean of the Mackay School of Mines at the University of Nevada, Reno.
Bipartisan Policy Center’s Task Force on Climate Remediation Research, Geoengineering: A National Strategic Plan for Research on the Potential Effectiveness, Feasibility, and Consequences of Climate Remediation Technologies (Washington, DC: Bipartisan Policy Center, 2011).
P. J. Crutzen, “Albedo enhancement by stratospheric sulfur injections: A contribution to resolve a policy dilemma?” Climatic Change 77 (2006): 211.
Anna-Maria Hubert, Tim Kruger, and Steve Rayner, “Geoengineering: Code of conduct for geoengineering,” Nature 537 (2016): 488.
Sabine Fuss, et al., “Betting on negative emissions,” 2014, Nature Climate Change 4 (2014): 850-853.
Jane C. S. Long, “Piecemeal cuts won’t add up to radical reductions,” Nature 478, no. 429 (2011).
Jane C. S. Long and Jeffrey Greenblatt, “The 80% Solution: Radical Carbon Emission Cuts for California,” Issues in Science and Technology 28, no. 3 (2012).
Jane C. S. Long and Dane Scott, “Vested Interests and Geoengineering Research,” Issues in Science and Technology 29, no. 3 (2013).
National Research Council, Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration (Washington, DC: National Academies Press, 2015).
D. E. Winickoff and M. B. Brown, “Time for a Government Advisory Committee on Geoengineering Research,” Issues in Science and Technology 29, no. 4 (2013).