Op-Ed

By David Keith and Daniele Visioni

Last week, an American-Israeli company that claims it’s developed proprietary technology to cool the planet announced it had raised $60 million, by far the largest known venture capital round to date for a solar geoengineering startup.

The company, Stardust, says the funding will enable it to develop a system that could be deployed by the start of the next decade, according to Heatmap, which broke the story.

As scientists who have worked on the science of solar geoengineering for decades, we have grown increasingly concerned about the emerging efforts to start and fund private companies to build and deploy technologies that could alter the climate of the planet. We also strongly dispute some of the technical claims that certain companies have made about their offerings.

Given the potential power of such tools, the public concerns about them, and the importance of using them responsibly, we argue that they should be studied, evaluated, and developed mainly through publicly coordinated and transparently funded science and engineering efforts. In addition, any decisions about whether or how they should be used should be made through multilateral government discussions, informed by the best available research on the promise and risks of such interventions—not the profit motives of companies or their investors.

The basic idea behind solar geoengineering, or what we now prefer to call sunlight reflection methods (SRM), is that humans might reduce climate change by making the Earth a bit more reflective, partially counteracting the warming caused by the accumulation of greenhouse gases.

There is strong evidence, based on years of climate modeling and analyses by researchers worldwide, that SRM—while not perfect—could significantly and rapidly reduce climate changes and avoid important climate risks. In particular, it could ease the impacts in hot countries that are struggling to adapt.

The goals of doing research into SRM can be diverse: identifying risks as well as finding better methods. But research won’t be useful unless it’s trusted, and trust depends on transparency. That means researchers must be eager to examine pros and cons, committed to following the evidence where it leads, and driven by a sense that research should serve public interests, not be locked up as intellectual property.

In recent years, a handful of for-profit startup companies have emerged that are striving to develop SRM technologies or already trying to market SRM services. That includes Make Sunsets, which sells “cooling credits” for releasing sulfur dioxide in the stratosphere. A new company, Sunscreen, which hasn’t yet been announced, intends to use aerosols in the lower atmosphere to achieve cooling over small areas, purportedly to help farmers or cities deal with extreme heat.

Our strong impression is that people in these companies are driven by the same concerns about climate change that move us in our research. We agree that more research, and more innovation, is needed. However, we do not think startups—which by definition must eventually make money to stay in business—can play a productive role in advancing research on SRM.

Many people already distrust the idea of engineering the atmosphere—at whichever scale—to address climate change, fearing negative side effects, inequitable impacts on different parts of the world, or the prospect that a world expecting such solutions will feel less pressure to address the root causes of climate change.

Adding business interests, profit motives, and rich investors into this situation just creates more cause for concern, complicating the ability of responsible scientists and engineers to carry out the work needed to advance our understanding.

The only way these startups will make money is if someone pays for their services, so there’s a reasonable fear that financial pressures could drive companies to lobby governments or other parties to use such tools. A decision that should be based on objective analysis of risks and benefits would instead be strongly influenced by financial interests and political connections.

The need to raise money or bring in revenue often drives companies to hype the potential or safety of their tools. Indeed, that’s what private companies need to do to attract investors, but it’s not how you build public trust—particularly when the science doesn’t support the claims.

Notably, Stardust says on its website that it has developed novel particles that can be injected into the atmosphere to reflect away more sunlight, asserting that they’re “chemically inert in the stratosphere, and safe for humans and ecosystems.” According to the company, “The particles naturally return to Earth’s surface over time and recycle safely back into the biosphere.”

But it’s nonsense for the company to claim they can make particles that are inert in the stratosphere. Even diamonds, which are extraordinarily nonreactive, would alter stratospheric chemistry. First of all, much of that chemistry depends on highly reactive radicals that react with any solid surface, and second, any particle may become coated by background sulfuric acid in the stratosphere. That could accelerate the loss of the protective ozone layer by spreading that existing sulfuric acid over a larger surface area.

(Stardust didn’t provide a response to an inquiry about the concerns raised in this piece.)

In materials presented to potential investors, which we’ve obtained a copy of, Stardust further claims its particles “improve” on sulfuric acid, which is the most studied material for SRM. But the point of using sulfate for such studies was never that it was perfect, but that its broader climatic and environmental impacts are well understood. That’s because sulfate is widespread on Earth, and there’s an immense body of scientific knowledge about the fate and risks of sulfur that reaches the stratosphere through volcanic eruptions or other means.

If there’s one great lesson of 20th-century environmental science, it’s how crucial it is to understand the ultimate fate of any new material introduced into the environment.

Chlorofluorocarbons and the pesticide DDT both offered safety advantages over competing technologies, but they both broke down into products that accumulated in the environment in unexpected places, causing enormous and unanticipated harms.

The environmental and climate impacts of sulfate aerosols have been studied in many thousands of scientific papers over a century, and this deep well of knowledge greatly reduces the chance of unknown unknowns.

Grandiose claims notwithstanding—and especially considering that Stardust hasn’t disclosed anything about its particles or research process—it would be very difficult to make a pragmatic, risk-informed decision to start SRM efforts with these particles instead of sulfate.

We don’t want to claim that every single answer lies in academia. We’d be fools to not be excited by profit-driven innovation in solar power, EVs, batteries, or other sustainable technologies. But the math for sunlight reflection is just different. Why?

Because the role of private industry was essential in improving the efficiency, driving down the costs, and increasing the market share of renewables and other forms of cleantech. When cost matters and we can easily evaluate the benefits of the product, then competitive, for-profit capitalism can work wonders.

But SRM is already technically feasible and inexpensive, with deployment costs that are negligible compared with the climate damage it averts.

The essential questions of whether or how to use it come down to far thornier societal issues: How can we best balance the risks and benefits? How can we ensure that it’s used in an equitable way? How do we make legitimate decisions about SRM on a planet with such sharp political divisions?

Trust will be the most important single ingredient in making these decisions. And trust is the one product for-profit innovation does not naturally manufacture.

Ultimately, we’re just two researchers. We can’t make investors in these startups do anything differently. Our request is that they think carefully, and beyond the logic of short-term profit. If they believe geoengineering is worth exploring, could it be that their support will make it harder, not easier, to do that?

David Keith is the professor of geophysical sciences at the University of Chicago and founding faculty director of the school’s Climate Systems Engineering Initiative. Daniele Visioni is an assistant professor of earth and atmospheric sciences at Cornell University and head of data for Reflective, a nonprofit that develops tools and provides funding to support solar geoengineering research.

Original post in MIT Technology Review

By Zeke Hausfather and David Keith

Since the Industrial Revolution, burning coal and oil has filled the air with sulfur, shortening the lives of billions of people. In response, countries passed stringent air pollution laws requiring coal plants to scrub out sulfur and ships to switch to cleaner fuels. Global sulfur emissions have fallen some 40 percent since 2006. China alone has slashed them by about 70 percent.

We should celebrate cleaner air, but we also have to reckon with an unintended consequence. It turns out that by reflecting sunlight back into space, tiny sulfur particles protected Earth from about a third of the warming caused by human emissions of carbon dioxide. Now more of the underlying greenhouse gas warming is showing through, accelerating climate change. As The Economist recently put it, “If India chokes less, it will fry more.”

For some of us in the world of climate science, this raises a thorny question: Should we explore replacing the inadvertent cooling effects of sulfur with a cleaner, deliberate version?

Geoengineering the climate in this way is not a new idea; it was in the first U.S. high-level climate report that reached President Lyndon Johnson’s desk in 1965. While several options have been proposed recently, the most plausible way to make Earth more reflective is to use a small fleet of high-altitude aircraft to increase the amount of sulfuric acid droplets in the upper atmosphere. We know this can work; when volcanic eruptions put large amounts of sulfur in the upper atmosphere, such as Pinatubo in 1991, Earth was noticeably cooler for a few years.

We should take such an idea seriously because the costs of losing accidental sulfur cooling were made painfully evident this year when heat waves pushed temperatures above 120 degrees Fahrenheit in the Middle East and North Africa. If sunlight reflection could save lives and protect the environment, it is at least worth discussing.

Because sulfur is much more effective at cooling the planet when put into the upper atmosphere compared with what’s released into the lower atmosphere when we burn fossil fuels, we’d have to add far less of it. And for the same amount of cooling produced from burning fossil fuels, sulfur in the upper atmosphere would cause at least 100 times smaller health impacts.

Sunlight reflection is no panacea. Putting sulfur in the upper atmosphere will damage the ozone layer, allowing more ultraviolet radiation through. Even if it reduces deaths from heat and extreme weather, large-scale deployment could exacerbate climate change in some locations, perhaps by shifting rainfall patterns.

There is also a more fundamental limitation to sunlight reflection. It is effectively a Band-Aid that treats the symptoms of climate change but not the underlying disease of greenhouse gases. And unlike a skinned knee, the Earth does not heal from climate change on any time scale that matters for human societies. Warming from carbon dioxide is astonishingly persistent; much of what we emit today will warm the planet for many thousands of years to come.

Even if the world drives emissions down to zero, the planet wouldn’t cool down for millenniums. The only durable way to return to cooler temperatures is to remove the excess carbon we have already added, and removing enough to reverse even 0.1 degree Celsius of warming would cost tens of trillions of dollars.

This means that the real risk of geoengineering is not some Hollywood-style catastrophe, but complacency. A cheap way to delay the effects of warming risks undermining the need to rapidly reduce emissions, and going down that path would risk locking our children into a dependency where even stopping the process becomes too expensive to contemplate.

Given all this, we are not advocating deploying geoengineering today. But if policymakers decide that it is needed, a more modest approach would be to run a small, carefully scaled program that slightly increases the upper atmosphere’s reflectivity to compensate for the loss of cooling as sulfur pollution is eliminated.

The goal would not be to dial the Earth to some preferred temperature, nor to offset all greenhouse warming. It would be to keep the total cooling from sulfur roughly constant for a period of time, reducing near-term climate risk while decarbonization efforts continue.

As world leaders gather in New York for the U.N. General Assembly and Climate Week, any discussions of sunlight reflection should have a clear, enforceable commitment to never cool the Earth more than today’s current sulfur emissions do. And it should come with a clear off-ramp: As the world reaches net-zero emissions and scales up carbon removal technologies later this century, the program should end.

Pacing matters as much as limits. If society ever chooses to test this approach, it should start small and move slowly. Tying it to reductions in air pollution allows a slow ramp-up, resulting in increments that are imperceptible to most of us but visible to satellites and sensors. This should be coupled with regular checkpoints to assess side effects on regional rainfall, the atmosphere and ozone. The intent is to buy a modest, temporary buffer, not to start a new arm of climate control.

If we stay focused on the cure of reducing emissions and consider bounded and temporary sunlight reflection, we could preserve cleaner air, avoid a near-term temperature surge and not betray the generations to come, who will live with the consequences of our choices today.

Original post in The New York Times. 

The following is a guest post by Joshua Horton, research director, geoengineering, at the Harvard Kennedy School; and David Keith, former professor of public policy and professor of engineering at Harvard University.

Solar geoengineering—the idea of using technology to reflect a small fraction of incoming sunlight away from Earth to partially offset climate change—poses many problems, including its potential to discourage emissions cuts, its uncertain distributive consequences, and the possibility that suddenly stopping implementation might result in dangerously rapid warming. And yet available evidence shows that moderate use of solar geoengineering may offer an opportunity to mitigate climate hazards beyond what is possible even if all emissions could be eliminated tomorrow. In our view, the prospect that solar geoengineering could significantly reduce risks for the world’s poorest, reducing income inequality, is a strong basis for pursuing research and international governance.

Debate on solar geoengineering, however, is haunted by a concern that such technology might be weaponized. This concern stems from longstanding military interest in weather modification technologies, most notably the U.S. use of cloud-seeding during the Vietnam War, which led to adoption of the 1976 Environmental Modification Convention (ENMOD) restricting hostile use of environmental modification techniques. It also stems from suggestions that governance of nuclear weapons may serve as a useful analog for governance of solar geoengineering.

Fears about the dual-use nature of solar geoengineering are sometimes stated explicitly (e.g., at 51:30 in this recent Rolling Stone debate), but more often implied in terms of vaguely defined security threats or speculation about “predatory geoengineering.” In a recent guest blog for the Internationalist, for example, Elizabeth Chalecki argues that “Just as nuclear fission can produce both weapons and energy, so too can geoengineering provide benefits if applied judiciously;” unsaid but insinuated is that solar geoengineering might also be used to wage war, which justifies placing it under international control in the same way the Baruch Plan of 1946 sought to internationalize atomic energy. (For other recent examples see here and here.)

The premise that solar geoengineering is weaponizable, however, is either false or grossly overstated and inapplicable to those technologies that might plausibly be deployed. Precision is a defining attribute of weaponry; indeed, the so-called revolution in military affairs has made it the most prized attribute for many strategists, as exemplified by the dominant role now played by precision-guided munitions. One hallmark of solar geoengineering, however, would be its imprecision.

Take stratospheric aerosol injection (SAI), which would disperse aerosols in the stratosphere to reflect sunlight and reduce some harmful aspects of climate change. SAI is the most prominent type of solar geoengineering and the one most associated with fears about weaponization. Yet injected materials cannot be contained along lines of latitude and would quickly encircle the globe. Some north-south control is possible, but only at a very crude level using just a few knobs like dispersing in equatorial versus polar regions or in northern versus southern hemispheres. Only climate effects—changes in average temperature and precipitation—could plausibly be induced; weather control at the level of individual storms or heat waves would be impossible to engineer. Moreover, there would be several steps between any induced climate change and the types of climate impacts—like changes in water availability or crop yields—that might affect states and societies in a somewhat predictable manner. There is simply no physical basis for believing that significant—large compared to natural variability—impacts could be targeted at the level of the nation-state.

Thus, SAI would be much too imprecise to function as a useful weapon. To take just one scenario, suppose the United States wished to attack Venezuela. The most predictable damage the United States could inflict using SAI would be a reduction in precipitation caused by dispersing aerosols solely in the southern hemisphere; doing so would shift the Intertropical Convergence Zone (ITCZ), an equatorial band of tropical rainfall northward, leading to decreased rainfall over Caribbean South America. But since the ITCZ circles the globe, this action would disrupt (sub)tropical precipitation worldwide. Indiscriminate climate modification of this nature would surely not be welcomed by China (America’s principal rival), India (the linchpin of America’s Indo-Pacific strategy), or Mexico (America’s southern neighbor and third largest trading partner).

Furthermore, the effect would be slow-moving within Venezuela, requiring perhaps years to determine whether reduced rainfall was responsible for observed impacts like droughts or food shortages. And it would be even harder to link this intervention to combat readiness, battlefield conditions, and other operational variables with clear implications for warfighting. Whatever strategic or tactical benefits might accrue to the United States, they would be dwarfed by the costs, risks, and uncertainties produced by worldwide rainfall disruptions affecting friends and enemies alike. SAI lacks the minimum level of precision—in space, time, and effect—implicit in the concept of a weapon.

The other two solar geoengineering technologies regularly discussed—low-level marine cloud brightening (MCB) using seawater spray to block incoming sunlight, and high-altitude cirrus cloud thinning (CCT) via dissipative seeding to enable more outgoing heat to escape the atmosphere—could be deployed with far more precision in space and time, yet it would still be extraordinarily difficult to use them to produce strong local effects, and such effects would inevitably cause significant distant consequences. It is conceivable that if MCB or CCT were deployed at global scale then they could be fine-tuned using meteorological data to enable limited weather control. But this is unproven, and even if possible, the physical consequences might be too diffuse or easily countered to have significant military value.

This is not to say that weaponization is utterly impossible. If solar geoengineering was implemented using low-Earth orbiting sunshades adjustable in real time, then some more precise military applications are imaginable. Yet this form of solar geoengineering is so far from practical reality as to be science fiction.

Weaponization might therefore be at least theoretically possible in a few exceptional cases, but in terms of real world policy relevance, the kinds of solar geoengineering that might plausibly be deployed in the next half-century—including SAI—would simply not be weaponizable. This conclusion does not depend on any assumption of goodwill, but instead follows directly from an understanding of the physical limits of practical technologies. For this reason, serious assessments of solar geoengineering—like the recently released National Academies of Sciences report—ignore the issue altogether.

This is encouraging, and yet the persistence of hints and suggestions that solar geoengineering might be weaponizable has the cumulative effect of helping shift attention away from hard, unavoidable problems toward more fantastical concerns regarding nebulous threats to national and global security. As discussions about solar geoengineering start to move from academic forums to policy circles, it is time to leave such distractions behind and focus more squarely on those aspects of this otherwise promising technology with real potential to cause harm and destabilize world politics.

Original post on Council on Foreign Relations

By David Keith

Solar geoengineering, also called solar climate intervention, is the idea that humans could make the planet a bit more reflective to reduce temperatures and other climate changes caused by accumulating carbon emissions. But at what cost?

A casual observer will read that geoengineering causes droughts, makes weather less predictable, dims the blue sky, and threatens the food supply of billions who depend on monsoon rains. And that’s the short list. But is it fair?

A technology’s risks depend on how it’s used. Antibiotics save lives, but if overused to make cheap beef in feedlots they breed deadly antibiotic-resistant bacteria. As with other technologies, the risks of geoengineering cannot be evaluated without a scenario for goals and governance. Like antibiotics, geoengineering could be deadly if overused.

A worthy goal for solar geoengineering is to slow climate change without making any region worse off. Plausible methods include spraying sea salt into the air to brighten marine clouds or injecting sulfur into the stratosphere to reflect some sunlight back to space. A fairly uniform application of geoengineering across the globe is less prone to make some regions worse off because atmospheric teleconnections mean that a strong localized application may cause unwanted climate changes elsewhere. While there will certainly be harmful impacts of geoengineering under such a scenario, evidence suggests that it would reduce heat waves, extreme storms, and rising seas, and the benefits would greatly outweigh direct physical risks, such as added air pollution. Studies suggest that such geoengineering would increase crop yields, and it would not perceptibly dim the blue sky. And because the benefits of reduced climate change are felt most strongly in the hottest and poorest parts of the world, it would reduce global income inequality.

An Internet search for “geoengineering and drought” turns up thousands of hits, most prominently a Guardian article titled “Geoengineering could bring severe drought to the tropics, research shows.” But despite widespread reporting, not a single scientific article demonstrates that geoengineering increases droughts. This disconnect is not confined to the popular press. The only article on geoengineering to make the cover of Nature, the world’s most prestigious scientific journal, did so under the headline “Veiled threat.” Yet the research article simply showed that geoengineering might not have an effect on crop yields, in contrast to previous research that suggested geoengineering would increase yields.

Why the sharp divergence between media and science? It’s driven, in part, by a well-intentioned sense of caution that solar geoengineering will weaken efforts to cut carbon emissions. This is geoengineering’s addiction problem, often called its moral hazard. If it encourages more fossil emissions by masking the climate pain they cause, then it is addictive because every ton of extra fossil carbon emissions increases climate risks, thereby increasing the demand for geoengineering to mask the pain.

It’s a reasonable fear. Heat waves, storms, and other climate changes grow in proportion to cumulative emissions of carbon. That is to the cumulative amount of coal, gas, and oil that humanity has used since the Industrial Revolution. Solar geoengineering acts quickly and temporarily, but it can only partially reduce climate risk, and it brings risks of its own. Suppose geoengineering were used to stop the rise in global temperatures while fossil fuel burning continued unabated. One would then need to keep increasing the geoengineering dose just to hold temperatures constant against the rising tide of carbon. This path leads to disaster.

Addiction is an apt analogy. Used wisely, morphine is a wonder drug, but using morphine to mask the pain while avoiding the exercise needed to cure it puts one on a path to disaster.

My guess is that many environmental scientists highlight the risks of geoengineering and downplay its benefits out of a well-founded concern of the potential for addiction. Many journalists share these instincts and further amplify this tendency, thus explaining the sharp divergence between media and geoengineering science.

The intentions are good, but the consequences are not. Decision-makers and the public they serve need balanced information about the effectiveness and risks of geoengineering. They are ill-served if the geoengineering’s real physical risks are conflated with the equally real political threat that geoengineering will be exploited by fossil fuel interest groups to block the transformation of our energy infrastructure away from carbon.

How to address the political risk of geoengineering addiction? First, the research community working on geoengineering must speak unequivocally about the dangers of the continued reliance on fossil fuels and confront attempts by fossil fuel interests to exploit geoengineering research by falsely arguing that it justifies inaction. More important, policy makers can build governance that links decisions about the implementation of geoengineering to accelerated efforts to cut emissions.

Climate advocates, including the big environmental groups, have generally avoided talk of geoengineering out of concern that it will divert attention from the urgent goal of cutting emissions. With a few exceptions, their strategy has generally been to wish the geoengineering issue away. There are three things wrong with this.

First, it’s not likely to go away. Some crude methods of geoengineering could be implemented cheaply with technologies accessible to all but the smallest countries. The likelihood that a coalition of countries facing extreme climate damages will move toward ill-considered deployment of geoengineering grows with the increase in climate risks and the gradual accumulation of knowledge and technological capability. Second, the wish-it-away strategy blocks development of a serious research effort that could reduce uncertainty. Less than 1 percent of climate science funds are focused on geoengineering. Finally, there is the prospect that geoengineering could substantially reduce climate risks for most humans and reduce the net human impact on the natural world.

We must be wary of errors of both commission and omission. The obvious nightmare is that the future possibility of geoengineering slows efforts to stop emissions but that the technology turns out to be infeasible. People are right to fear over-reliance on technofixes. But there’s another nightmare: It’s that after bringing emissions to zero, we realize in hindsight that early use of geoengineering could have saved millions of lives lost in heat waves and helped preserve some of the natural world. The rise of the antivax movement sadly demonstrates the dangers of prejudice against life-saving technologies.

There are no easy answers. Both errors are possible. But societies have the best chance to make good decisions if they distinguish the very real political risks of geoengineering addiction from the equally real physical risks and benefits of solar geoengineering. It would be crazy to start deploying solar geoengineering today. It’s perhaps equally crazy to keep ignoring it. Our children will be better served by a serious international open-access research effort coupled with stronger action to end the world’s reliance on fossil fuels.

Original post on Boston Globe

By David Keith

Negotiations on geoengineering technologies ended in deadlock at the United Nations Environment Assembly in Nairobi, Kenya, last week, when a Swiss-backed proposal to commission an expert UN panel on the subject was withdrawn amid disagreements over language. This is a shame, because the world needs open debate about novel ways to reduce climate risks.

Specifics aside, the impasse stemmed from a dispute within the environmental community about growing scientific interest in solar geoengineering – the possibility of deliberately reflecting a small amount of sunlight back into space to help combat climate change. Some environmental and civil-society groups, convinced that solar geoengineering will be harmful or misused, oppose further research, policy analysis, and debate about the issue. Others, including some large environmental groups, support cautious research.

By reflecting sunlight away from the Earth – perhaps by injecting aerosols into the stratosphere – solar geoengineering could partly offset the energy imbalance caused by accumulating greenhouse gases. Research using most major climate models suggests that solar geoengineering might reduce important climate risks such as changes in water availability, extreme precipitation, sea level, and temperature. But any version of this technology carries risks of its own, including air pollution, damage to the ozone layer, and unanticipated climate changes.

Yet research on solar geoengineering is highly controversial. This has limited research funding to a few tiny programs around the world, although a larger number of climate scientists are beginning to work on this topic using existing funds for climate research.

Why the controversy? Many fear, with good reason, that fossil-fuel interests will exploit solar geoengineering to oppose emissions cuts. But most researchers are not driven by such interests. The vast majority of those researching solar geoengineering or advocating for its inclusion in climate-policy debates also support much stronger action to reduce emissions. Still, it’s very likely that Big Fossil – from multinational energy companies to coal-dependent regions – will eventually use discussion of geoengineering to fight emissions restrictions.

But that risk is not a sufficient reason to abandon or suppress research on solar geoengineering. Environmentalists have spent decades fighting Big Fossil’s opposition to climate protection. And although progress to date has been insufficient, there have been some successes. The world now spends over $300 billion per year on low-carbon energy, and young people are bringing new political energy to the fight for a safer climate.

Open discussion of solar geoengineering would not weaken the commitment of environmental advocates, because they know emissions must be cut to zero to achieve a stable climate. At worst, such a debate could make some in the broad, disengaged middle of the climate battle less interested in near-term emissions cuts. But even this is not certain; there is empirical evidence that public awareness of geoengineering increases interest in cutting emissions.

It is sensible to focus on cutting emissions, and reasonable to worry that discussing solar geoengineering could distract from that fight. But it’s wrong to indulge a monomania whereby emissions cuts become the sole objective of climate policy.

Vital as it is, eliminating emissions simply stops adding to the burden of carbon dioxide in the atmosphere. The CO₂ from the fossil-fuel era, and the resulting climate changes, will persist. We need adaptation that increases resilience to climate threats. But adaptation by itself is no solution. Neither is solar geoengineering. And nor is removing CO₂ from the atmosphere – another emerging set of technologies that were considered in the Swiss-backed proposal in Nairobi.

As the American writer H.L. Mencken put it, “there is always a well-known solution to every human problem – neat, plausible, and wrong.” Complex problems like climate change rarely have a single solution.

My hope is that emissions cuts, solar geoengineering, and carbon removal can work together to reduce the human and environmental effects of climate change beyond what is possible with emissions cuts alone.

Are these hopes justified? The geoengineering research community is small and dominated by a narrow group of members, most of whom are (like me) white, male, and based in Europe or America. Groupthink is a distinct possibility. We may simply be wrong. It would be reckless to deploy solar geoengineering based only on hope and early research.

Instead, an international, open-access research program could, within a decade, dramatically improve understanding of the risks and efficacy of solar geoengineering. Such a program would cost a small share of the sum currently spent on climate science, and far less than 0.1% of outlays to cut emissions. A wise program would reduce groupthink by increasing the diversity of researchers, and by establishing a deliberate tension between research teams developing specific scenarios for deployment and others tasked with critically examining how these scenarios could go wrong.

Governance is the toughest challenge for geoengineering. A global research program should therefore be coupled with greatly expanded international discussion about these technologies and their governance. Such a debate was unfortunately cut short in Nairobi last week.

Although my generation will not use solar geoengineering, it seems plausible that before the middle of this century, a dramatic climate catastrophe will prompt some governments to consider doing so. By foregoing debate and research on geoengineering now, political leaders may be hoping to eliminate the risks of its future misuse. But their stance may actually increase this danger.

Humans rarely make good decisions by choosing ignorance over knowledge, or by preferring closed-door politics to open debate. Rather than keeping future generations in the dark on solar geoengineering, we should shed as much light on it as we can.

Original post on Project Syndicate

At the time of this post, David Keith was a professor in Harvard’s Schools of Engineering and of Public Policy, and founder at Carbon Engineering.

Edward Parson is professor and co-director of the Emmett Institute on Climate Change and the Environment at UCLA, and senior research associate at the Centre for Global Studies, University of Victoria.

People’s initial reactions when they learn about the prospect of solar geoengineering typically involve some mix of horror and relief: horror at the prospect of a dangerous and uncontrolled technical fix, and relief that new technologies may offer the prospect of additional reductions in this century’s severe climate risks.

But wherever your views fall on this spectrum, the case for serious research on solar geoengineering, and serious examination of its governance challenges, is compelling. Indeed, it is becoming increasingly likely that some form of climate engineering will be necessary to achieve the Paris target of limiting planetary heating to well below 2 C.

Solar geoengineering – one type of climate engineering – would involve reflecting a small amount of incoming sunlight back to space. The most plausible method is to use aircraft to make a fine mist of reflective material in the stratosphere, where it would act like a thin cloud reflecting a little sunlight back to space. Neither science fiction nor saviour, the goal of such intentional climate intervention would be to offset some of the climate changes caused by elevated greenhouse gases.

Most climate models agree that carefully managed solar geoengineering can reduce projected changes in both temperature and precipitation over nearly all the Earth’s land surface. It can slow and likely reverse sea level rise, and provide some reduction to rapidly mounting threats to coral reefs, by slowing both rising temperatures and ocean acidification. It appears particularly effective at slowing current and projected increases in the strength of tropical hurricanes.

How should the world consider climate engineering? As a taboo, pushed aside from the centre of climate policy? Or, as a risky solution embraced all too quickly by opponents of emissions cuts? Between these polar extremes lies a wide range of opportunities for responsible exploration – and a great opportunity for Canada to exercise effective international leadership.

Solar geoengineering should be considered along with another form of climate engineering – removing previously emitted carbon dioxide from the atmosphere, often called “negative emissions.”

Geoengineering approaches are, at best, supplements to emissions cuts, not substitutes for them. Emission must still be cut. But early evidence suggests that a combination of emissions cuts, carbon removal and solar geoengineering could provide better protection against climate risks, perhaps substantially better, than emissions cuts alone. Such strategies could stop and even reverse the progression of climate change.

Solar geoengineering – our focus here – offers both the high-stakes prospects of large potential benefits and serious grounds for concern. The most basic concerns pertain to how well it could work and its environmental impacts and risks. Early research has shown surprisingly promising results, quite at odds with a few widely circulated, overconfident claims of harms: e.g., that it would destroy the South Asian monsoon or distribute large regional gains and losses. Yet there is plenty of uncertainty, and additional limits and risks, not presently identified, will surely be found.

The strongest grounds for concern pertain to how solar geoengineering would be used and governed. Ensuring that it is used (if used at all) in ways that bring global benefits, fairly distributed, with any attendant harms minimized and justly compensated, presents novel challenges to global governance. The politics will be hard and may be ugly. Forces opposing emissions cuts – mainly fossil-fuel interests – may exaggerate claims of solar geoengineering’s effectiveness, or use the new uncertainties it introduces to argue for further delay in cutting emissions. The reasonable fear that solar geoengineering may be exploited to obstruct needed emissions cuts underlies much of the resistance bringing this topic out of the shadows.

Uncertainty about the effectiveness and risks of solar geoengineering should be addressed with a serious research program. Such research would include both modelling and small field experiments. Some have expressed concerns that doing this research would inevitably lead to the technology’s deployment. But these claims are belied by abundant historical experience, and – if true to any degree – are easy to mitigate by careful design and management of research programs.

Longer-term questions about how to govern future proposals to use solar geoengineering need serious critical examination, and the sooner, the better. But this is not a reason against pursuing scientific and technical research, particularly when the risks of solar geoengineering are weighed against the increasingly severe and intractable risks of climate change itself. Yet on both the research and governance fronts, progress has stalled. The United States saw promising steps toward developing a federal research program in the past two years of the Obama administration, including recommendations to that effect from both a National Academy of Sciences committee and the U.S. Global Change Research Program.

But, as in so many areas, the Trump administration has changed the game, and not for the better. Considering its retreats from responsible climate-change policy, from international co-operation, and from science, many parties now fear that this administration’s embrace of these technologies would do more harm than good.

A Trump tweet such as “Geoengineering is GREAT, no need to cut emissions” might be the worst case, but promotion of solar geoengineering research by agency officials or Congressional leaders who deny the severity of climate change, pursue expansion of fossil fuels, and demean scientific research when they don’t like the results would not be much better.

Research is needed, but it must take place under conditions that make it more likely to help than hurt. The first condition is that expanded scientific and technical research must proceed in parallel, and be linked, with deliberation and development of international governance. A substantial research effort without governance would be reckless, yet effective governance cannot be developed without understanding the technologies that need to be governed – knowledge that can only be developed through research. Achieving linked progress in research and governance will be a delicate, iterative process, which will succeed or fail based on careful institutional design and trust in the leadership of both endeavours.

That need for trust is the second condition. The institutions leading these endeavours – whatever combination of governments, scientific bodies and other non-governmental organizations – must inspire and earn trust through a track record and commitment to international consultation and co-operation, to serious action on climate change that prioritizes strong emissions cuts and adaptation efforts, and to the constructive and impartial use of scientific knowledge and evidence in public policy.

Does this sound like Canada? We think so. While Canada’s record on these matters is not perfect – indeed, Canada has at times exhibited an unfortunate gap between climate rhetoric and action – its quiet virtues and present commitments shine brighter in view of the chaos enveloping our southern neighbour. Canada has other advantages, too, that can help it play a leading role in developing responsible research and governance for climate engineering: its status as a middle power in international affairs; its exposure, as an Arctic nation, to some of the most rapid and extreme manifestations of global climate change; its strong record of effective science-based environmental assessment and advisory processes; and its strong base of scientific expertise in relevant areas such as climate modelling, stratospheric dynamics, remote sensing, ecological system studies and Arctic ecosystems, and the cryosphere.

A serious Canadian initiative to lead global efforts on climate engineering research and governance might include the following elements. First, federal funding for relevant investigator-driven academic work. Second, directed federal funding for applied research and development at agencies such as the Canadian Climate Centre, the Canadian Space Agency, and NRC. Third, establishment of a senior advisory committee on climate engineering governance, jointly convened by the Ministries of Environment and Climate Change, and Global Affairs, with substantial participation from scientific, environmental and other relevant civil-society groups. Finally, last but not least, a broad effort to foster public consultation and deliberation.

In pursuing such an initiative, Canada would not be acting entirely alone. Tiny tentative research efforts are developing in Europe, China and elsewhere. But a crucial leadership void exists, in developing a vigorous research agenda and in the linked development of governance. Canada is uniquely well positioned to provide that leadership. Canadian engagement could steer international debate on how, and whether, these technologies can be developed and used, prudently and justly, in addressing the grave threat that climate change poses to this divided planet.

Original post on The Globe and Mail