Climate Change News

Study Will Examine Risks and Benefits of Climate Interventions

A National Academies committee is working to develop a research agenda for geoengineering strategies that reflect sunlight to cool Earth.


With growing concerns about the impacts of climate change, a new study is examining whether controversial geoengineering approaches to try to cool Earth should be considered along with mitigation, adaptation to unavoidable climate change impacts, and other measures.

A committee of the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM) has started working on developing a research agenda and exploring and recommending appropriate research governance approaches for climate intervention (CI) strategies that reflect sunlight to cool Earth.

The committee, which held its first meeting on 30 April, is focusing on looking into sunlight reflection strategies that involve atmospheric interventions, according to the committee’s statement of task. These strategies include marine cloud brightening, stratospheric aerosol injection, and cirrus cloud modification.

The committee plans to consider estimating the potential positive and negative impacts and risks of these interventions on the atmosphere, climate system, natural and managed ecosystems, and human systems and what research and research infrastructures are needed, according to the statement.

A related committee document states that “preliminary modeling work indicates that these approaches do have the potential to reduce some near-term risks of climate change.” However, that document adds that these approaches introduce potential environmental, ethical, social, political, economic, and legal risks, and concerns about these risks have constrained research on the topic.

How Do You Balance the Risks?

How to balance the risks from climate change against the potential risks from possible solar climate interventions “is a really hard question,” committee cochair Christopher Field told Eos.

“That’s part of the reason that we would want to understand much more about the potential of the interventions and their risks before even having any kind of serious discussion about whether they should be included in a portfolio of responses” to climate change, said Field, a climate scientist who is director of the Stanford Woods Institute for the Environment at Stanford University in California. “We are just way too early in the development of the dialogue to have a mature response to that.”

Field added, “If there were no pressure from a changing climate, there would be no pressure to learn more about the prospects for diverse kinds of solutions.”

The committee, which is building on an earlier 2015 NASEM report on climate intervention, also plans to look into governance mechanisms that could encourage public participation and consultation in research planning and oversight and that could ensure transparency and accountability about a project, including a project’s potential risks.

The Right Timing for a Study

“We think the timing is right for a comprehensive study, such as the one that the National Academy of Science (NAS) completed in 2015, given the increasing interest in this issue and large remaining uncertainties in both the scientific and governance arenas,” according to a statement by the National Oceanic and Atmospheric Administration (NOAA), one of the study’s sponsors. David Fahey, director of the Chemical Sciences Division of NOAA’s Earth System Research Laboratory in Boulder, Colo., presented the statement at the meeting.

However, the statement continued, “our support for this study should not be interpreted as reflecting support for future implementation of [climate intervention] methods to reflect sunlight.”

The study’s results “will provide the Nation and the international community our best available understanding of the weather and climate implications and risks of [climate intervention] proposals in advance of any future implementation decisions,” according to the statement.

The statement also expressed NOAA’s hope that the committee’s subpanel on governance will “recognize that CI governance is an international issue, driven from the fact that there is but ‘one atmosphere’ shared by all nations.”

In addition to reading the statement, Fahey noted that the committee’s work could help to guide NOAA’s efforts. “There is no federal program for geoengineering,” although there is a lot of research relevant to geoengineering, he said.

“The elephant in the room here is urgency,” Fahey continued. “Urgency tends to override all of these nicer considerations about ‘should we do it’ and ‘what about the balance of risks.’”

Fahey said that “the U.S. should be at the table, like all other nations, talking about what’s the risk of doing nothing about trying to mitigate climate change with geoengineering versus doing something with it.”

Taking a Hard Look at All Possible Approaches

“There are real risks that we may not get there in terms of limiting dangerous climate change only through the technologies that many of us prefer,” committee member Peter Frumhoff told Eos. “From my perspective, solar geoengineering is like the worst possible way to address climate change that we need to take seriously.” Frumhoff is director of science and policy and chief climate scientist at the nonprofit Union of Concerned Scientists.

“We are no longer at the point in time when, from my perspective, we can avoid taking a hard look at all possible approaches, even those we don’t love, and we may ultimately reject them,” he said.

Frumhoff added that discussion about climate interventions should not be driven by scientists but should involve a variety of stakeholders, including the most climate-vulnerable nations and communities.

Stakeholder Perspectives

At the meeting, stakeholders expressed a variety of perspectives about proceeding with geoengineering.

“We view the sunlight reflection techniques as currently among the most high probability options for short-acting solutions to disruptive change. They may be very important in that regard from the point of view of protecting people, ecosystems, and economic systems” from the threat of climate change, said Kelly Wanser, executive director of SilverLining, a Washington, D.C.–based nonprofit whose mission is to drive research to improve the ability to forecast climate and understand the risks and feasibility of interventions to reduce warming.

Janos Pasztor, executive director of the Carnegie Climate Geoengineering Governance Initiative of the Carnegie Council for Ethics in International Affairs, emphasized that research on solar radiation management “should not be considered to be an alternative to research on, and implementation of, emission reductions and renewables.”

Michael Stoever, a legislative assistant to Rep. Jerry McNerney (D-Calif.), said that although the top commitment to dealing with climate change should be reducing carbon emissions, there needs to be “a robust science agenda” for climate intervention strategies that reflect sunlight to cool Earth to provide guidance to policy makers, U.S. agencies, and the broader research community. He added that “the overarching goal of any mitigation efforts are to ensure the safety for people and the stability of natural systems in the face of near-term climate risks.”

“The committee should recognize and acknowledge the strong and very widespread opposition to these forms of geoengineering within civil society and social movements across the world,” said Lili Fuhr, another speaker at the meeting. Fuhr is head of the Ecology and Sustainable Development Department of the Heinrich Böll Foundation, a nonprofit affiliated with, but independent of, the German Green Party.

How We Got to This Point

Committee member Andrew Light told Eos that society has gotten to the point of needing to seriously consider climate interventions “because, frankly, we’ve been too slow in responding to the problem of climate change.”

Light, a professor of philosophy, public policy, and atmospheric sciences at George Mason University and a senior fellow in the climate program at the nonprofit World Resources Institute, said that he doesn’t know anybody in the research community who seriously imagines that climate interventions would be a substitute for climate mitigation.

“But the fact of the matter is that we know enough now about how quickly the climate is changing and how bad the impacts are going to be if we don’t meet some of the internationally agreed upon targets that we have right now, that we have to consider whether this [climate interventions] is possible,” he said. “I would like to know what we don’t know about these kinds of proposals which have been around for decades.”

“We can’t afford to take anything off the table,” he added.

—Randy Showstack (@RandyShowstack), Staff Writer

Citation: Showstack, R. (2019), Study will examine risks and benefits of climate interventions, Eos, 100, Published on 13 May 2019.
Text © 2019. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.