The Climate Overshoot Commission Releases Its Report, Pts. 2 & 3

[Note from BenIndy Contributor Nathalie Christian: This is a long read, but a good one. After the first installment of Ted Parson’s three-part series introduced climate overshoot as a concept and offered a quick history of the Climate Overshoot Commission, these two follow-up parts explain just what is so interesting – and potentially so radical– in the Commission’s recently released report. As someone who studied the Montreal Protocol (briefly), I always wondered what was so different about the rules, systems, and concepts our global society deployed to reduce ozone-destroying CFCs (et al.) and the rules, systems, and concepts we are using now in our fight against the fossil fuels–induced climate crisis. “Money! Dump-trucks of money!” is of course the most obvious answer to any and all questions, but there’s more potential overlap for success that awaits you in this fascinating two-part finish to Parson’s analysis. I have emphasized key lines through this post to assist fellow skimmers, and marked when I have done so, but I hope many of you read the whole thing.]

Pt. 2, A Radical Proposal Hidden in Plain Sight in the Overshoot Commission Report

Click the image to read the full report on the Climate Overshoot website.

The Commission’s recommendations on emissions include a fossil phaseout much stronger than anything now proposed, which could materially advance climate action.

Legal Planet, by Ted Parson, September 21, 2023

Edward A. (Ted) Parson is Dan and Rae Emmett Professor of Environmental Law and Faculty Co-Director of the Emmett Institute on Climate Change and the Environment at the University of California, Los Angeles.

Continuing my discussion of the report of the Climate Overshoot Commission released last week, today I dig into their recommendations on mitigation. As you may recall, the Commission’s informal (but serious) job description was to speak of elephants in the room and unclothed emperors: to say things that are true and important about climate risks and responses that other, more political constrained bodies cannot. If you take this job description for statements and apply it to recommendations, it would suggest recommending things that are not politically feasible – at least not now – or that even lie outside the range of current debate. This does not mean making recommendations so outlandish or implausible that they can readily be ignored or arbitrarily rejected, of course. But if the job is to move the range of acceptable arguments and proposals – moving the Overton window, as the political scientists say – the most effective recommendations may well lie beyond the boundary of what could be adopted now. This perspective is especially relevant to the Commission’s recommendations on mitigation.

Mitigation – deep rapid cuts to worldwide emissions – is the first, essential element of effective climate response. I don’t think there’s anyone thinking seriously about climate change who disagrees with this. In the Commission’s words, mitigation is the “foundational strategy.” Yet when the Commission began its work, it first planned not to speak about mitigation – not because they didn’t recognize its primary importance, but because they thought there wasn’t much for them to add to what’s already being said, particularly given the tight time limit on their work. But partway through, the Commissioners realized that not speaking on mitigation would risk them being mistakenly seen to not accord it the needed priority, so they changed course – correctly, even necessarily, in my view. But in making this decision, they also resolved that their messages on mitigation had to cut through the noise and move the debate, and thus sought to make their recommendations radical. I think they succeeded at this, although it’s not clear from the initial reactions to their report that their radicalism has been noticed – yet.

Their mitigation recommendations include calls to adopt stronger national and international accountability mechanisms for emissions cuts; policy and financing innovations to promote faster deployment of zero-emissions technologies; and for countries to recognize each other’s climate policies and reflect them in trade measures. They also call for cutting short-lived climate forcers even faster than now being pursued. These are strong recommendations, persuasive and well conceived. But they also could plausibly be adopted within a few years if governments are serious about ramping up their ambition, so do not necessarily meet the aim of proposing something radical enough to move the debate.

So, where’s the radicalism?

It’s in their very first mitigation recommendation, for a “graduated, differentiated phaseout” in production and consumption of fossil fuels. Wait a second, you might say, what’s so radical about that? Isn’t it obvious that the world needs to get rid of fossil fuels, and haven’t a bunch of people called for it? Well, yes. But the Commission’s proposal is vastly stronger than either the weak language adopted at Glasgow – which calls on parties to “… accelerat(e) efforts towards the phasedown of unabated coal power and phase-out of inefficient fossil fuel subsidies …” or the language now being discussed for the coming COP28, which speaks of phasing out unabated fossil fuels. The word “unabated” has been used frequently in recent months by Sultan al-Jaber of the United Arab Emirates who is overseeing this year’s COP; it was included in a draft document by EU countries; and it appears in the mitigation findings of the global stocktake released earlier this month. The Commission’s proposal is also substantially stronger, and at the same time more practical, than the most ambitious fossil-fuel proposals being promoted by activist nations: the Fossil Fuel Non-Proliferation Treaty and the Beyond Oil and Gas Alliance.

What makes the Commission’s proposal so radical is the combination of its ambition; its inclusion of key design elements that make it plausibly operationalizable; and the stature of the Commission. No mitigation proposal remotely this strong has been advanced in policy debate, certainly not by any body with stature similar to the Commission’s.

It is these elements taken together that make the Commission’s proposal radical.

Even better, they might position the proposal in that sweet spot that actually makes change, where the “radical and transformative” overlaps with the “close enough to feasible that it can’t be arbitrarily dismissed or quietly ignored.”

There are three points of the proposal that support this claim. First, it’s expressed in terms of production and consumption of fossil fuels, not emissions or net emissions. Second, it calls for a phaseout of these. And third, in a few key design elements it is modeled on the provisions to cut CFCs in the Montreal Protocol – the only international environmental regime that has achieved a socio-technical transformation of remotely the scale required for greenhouse gases. I’ll discuss the first two points briefly, then unpack the third in a bit more detail.

Targeting fossil fuels not emissions.

First, the Commission’s proposal does not target greenhouse-gas emissions (or even worse, net emissions), but instead targets a concrete, readily observable proxy for emissions, fossil fuels – and not just some fossil fuels, all of them. [Emph. added by BenIndy.] Fossil fuels are responsible for the dominant share of emissions – more than two-thirds of anthropogenic emissions, although the arithmetic to precisely estimate this fraction is confused by the fact that some human emissions cool as well as heat. (And for even more confusion, those cooling emissions are linked to fossil-fuel combustion when the fuel contains sulfur– those fine particles I discussed in my last post that are giving us a cooling bonus, while also killing millions of people a year.) In addition to being a strong proxy for greenhouse-gas emissions, fossil-fuel production and trade is observed, documented, and regulated in nearly all jurisdictions.

To understand why targeting fossil fuels instead of emissions is so important, you need to simultaneously hold two ideas in your head that may seem contradictory, but are both true. First, what the Earth system sees and what actually matters for climate change is net emissions. This isn’t even net anthropogenic emissions: it’s net emissions from all sources and sinks, including human ones, natural ones, and all the feedbacks that link the two. Second, if you are serious about actually making large changes in human environmental burdens, in the context of a massively complex linked human-natural system, “net emissions” is an utterly impractical metric to use for control. [Emph. added by BenIndy.] Even total emissions from a country or legal entity (without the “net”) can’t be observed directly, but must be inferred from inventory processes that are chock-full of too-coarse, out-of-date, suspect, manipulable assumptions, and dependent on weak, mostly voluntary, and inconsistently controlled reporting processes. Take the additional step to “net emissions” (my enterprise’s, my industry’s, my city’s, or my country’s), and it’s everyone make your own adventure – an accounting artifact chock-full of opportunities for double-counting, unobservable and inflated counter-factuals, and enormous effort (and expense) spent not to actually reduce or remove emissions, but to ensure that the removals get credited to my books and the emissions debited to somebody else’s. That net emissions has emerged as the dominant metric to measure and claim credit for climate action – when it is so full of holes, so impractical for counting anything you actually care about – is mystifying. Nothing in this rant negates the first proposition above, that net emissions really is the measure that matters for the climate. It is. It’s just impossible to measure and control, and likely to remain so for as long as it matters for actually getting emissions down. The Commission’s proposal is the first from a body of its stature that holds the promise of cutting through this mountain of delusion.

A phase-out, not a phase-down.

Second, the proposal calls for these fossil fuels to be phased out – not “phased down,” as in the weak final language of the COP26 Glasgow Climate Pact; nor a phaseout of “unabated” fossil fuels, as is now being discussed in the run-up to COP28. A “phasedown” is intentionally ambiguous about how far it goes. A phaseout of “unabated” fossil fuels shifts the target away from the fuels themselves toward some undefined subset that are “unabated” (with plenty of slop over what “abated” actually means). This in turn centers the argument back on carbon capture and removal instead of reductions, and shifts the control metric back toward “net emissions” – even though it’s ostensibly about fossil fuels. In contrast, the Commission’s proposal puts the zero target on the fuels themselves, without escape language built into the target. Knowing that something is really going away has a wonderfully clarifying effect. As Samuel Johnson said of knowing you are going to be hanged in a fortnight, it “concentrates the mind wonderfully.” It doesn’t matter that the zero endpoint is not immediate. It doesn’t even matter much if the timeline to get there is pretty long relative to what optimally prudent climate control might call for. It can, for example, be long enough to allow capital recovery for many investments made before adoption of the phaseout, as the Commission notes. The crucial factor is adopting a credible early commitment to move to zero, even if it takes a while to get there. This will immediately convey that the sector is now a terrible business proposition and chill new investment accordingly. [Emph. added by BenIndy.] It will thus achieve the top-line aims of both the Fossil-Fuel NPT proposal and the Beyond Oil and Gas Alliance – quickly stopping development of new or expanded production – but in a way that harnesses rather than fighting against market forces.

Invoking the successful Montreal Protocol. 

Third, the proposal is modeled on, and adopts a few key design elements from the extraordinarily successful provisions of the Montreal Protocol to cut CFCs and other ozone-depleting chemicals. Picking up these elements invokes the powerful symbolism of the only global environmental regime to have achieved a socio-technological transformation of remotely the scale required for greenhouse gases. In addition, and more concretely, these elements give credibility and force to the proposal, because they are the main points that enabled the Montreal Protocol to achieve what many thought impossible, and do it faster than even the most optimistic expected.

There is a lot to unpack in the parallels between the Commission’s proposal and the Montreal Protocol, far too much to do justice to in one post. And there are some real problems in porting the model from ozone-depleting chemicals to fossil-fuels, which will need serious effort to work out and may ultimately turn out to be unresolvable. But there are good reasons to hope that with creative design and strategy, these elements may be transportable. To the extent they are, they may make the proposal something that governments actually can do – and thus hold the promise of driving bigger and faster changes than any mitigation proposal currently being considered.

With apologies for putting numbered lists within numbered lists, I’ll unpack and discuss four of these design elements that the Commission proposal takes from the Montreal Protocol.

  • First, the proposal phases out both production and consumption of fossil fuels, on the same schedule. Other current proposals target only production. [Emph. added by BenIndy.] But trying to eliminate a socially destructive product by squeezing only on the supply side is a self-defeating strategy, as decades of failed US policy to control illegal drugs from the supply side have shown. This “both-sides” strategy also reflects a key insight gained partway through the Montreal Protocol negotiations, that fighting over whether responsibility for a damaging product – and the initial duty to cut – lies with the producer or the consumer can be a long, fruitless battle, particularly when you know the eventual endpoint is zero. After all, at that point no one will be either producing or consuming, and all the burden-shifting fights along the way just delayed you getting there. Moreover, to avoid additional fruitless fights over how to define and measure consumption (which is in fact harder than for production), the Protocol adopted the simplest possible definition: national consumption equals production plus imports minus exports in a single year. Yes, this neglects change in inventories, but they judged it close enough and it worked. This aspect of the Commission’s proposal cuts through the entire thicket of problems and conflicts associated with emissions accounting and inventory procedures. It eliminates incentives to move emissions around rather than reducing them. [Emph. added by BenIndy.] And it makes it impossible for fossil-producers – whether firms or exporting jurisdictions – to claim that the bulk of the emissions from their products are their customers’ problem because it shows up on their books. Nope, now it’s both of your problems.
  • Second, the proposal makes gradual phased reductions, which start out easy – a freeze at current levels – then get harder on a practical time-scale. I’ve already mentioned the bracingly clarifying effect of explicitly making the eventual target zero. But with that established, you can reduce near-term disruption by making the first control step real and binding, but not particularly difficult. Taking that first real control step – not just setting up a process, not promising future cuts from some manipulable baseline – has a motivating and action-focusing power almost independent of its quantitative level. [Emph. added by BenIndy.] This insight comes from something the negotiators of the Montreal Protocol got wrong. For months they haggled over whether the controls in the first-generation 1987 treaty should be a freeze, a 20% cut, or a 50% cut (they settled on 50%), but in retrospect the difference between these mattered little. The correct schedule, or the maximum feasible schedule, can’t be known in advance: these are moving targets that change along the way as you make the reduction efforts and see the results. Rather than the initial control level or schedule of cuts, the crucial feature – of both the Protocol and the Commission proposal – is the requirement to repeatedly revisit and adjust the schedule based on new knowledge and technical progress. In the Montreal experience – which I suspect will likely be replicated for fossil fuels – the work to meet the earlier, less demanding cuts repeatedly made meeting the later, tighter ones easier. I guess “seek and ye shall find” applies to environmental innovation as well as spiritual insight. This adjustment mechanism in the Protocol is often called a “ratchet,” but I find the analogy a bit misleading. When you’re pulling something with a cable and ratchet, it often gets harder to pull with each click. But under the Protocol later steps sometimes turned out easier than earlier ones, because innovation around the controlled materials outpaced the tightening limits. Similar processes may well operate here.
  • Third, the proposal is differentiated by development status. The reduction and phaseout schedule builds in a substantial grace period for developing countries, even allowing near-term expansion. This is necessary both for reasons of equity and pragmatism. [Emph. added by BenIndy.] So long as the global total comes down, it’s OK to share room under the near-term constraint with lower-income countries. This does of course imply the need for even faster cuts in the industrialized countries. [Emph. added by BenIndy.] The Commission calls for rich countries to provide this headroom by expanding their removals so rapidly that they move far into net-negative territory by mid-century. (Note: I’m not forgetting the serious accounting and credibility problems with net-emissions accounting that I complained about above. But the worst thing about these is that they provide potentially unlimited room for fossil-fuel continuance and expansion, problems that will be less severe in the context of ongoing deep cuts to these fuels.) Rightly wary of the risk that his headroom may create a new class of entrenched Petro-states, the Commission stresses that this differentiation is not a blank check: it is a time-limited opportunity to access resources for development, after which everyone is on the same train to zero.
  • Finally, perhaps most important, the phaseout comes with an exemption for essential uses. [Emph. added by BenIndy.] This is modeled on the Montreal Protocol process managed by the Technology and Economics Assessment Panel (TEAP). It provides the pressure-relief valve that keeps the program viable as cuts start to bite. That pressure-relief valve in turn protects the program from overwhelming pushback, and thus keeps the continued movement toward zero credible. But it achieves this relief in a fundamentally different way from the current approach on GHGs, which changes the goals from emissions to net emissions via “net-zero” targets. Net-emissions targeting and scoring has no mechanism to reliably tell if net-zero really is net-zero, and no criteria to judge how many emissions, and which ones, get to continue because they are (supposedly) offset by real, long-term-stable, not double-counted removals somewhere else. In place of this free-for-all, an essential-use-exemption process makes elimination the default and requires making an affirmative case that specific uses are in fact essential. It puts these determinations in an impartial, technically competent, international process. And crucially, it make exemptions time-limited, not perpetual, so exempted uses must periodically make the case again that they are still essential, and no viable alternatives are available, as technology advances. [Emph. added by BenIndy.]

The Commission’s proposal is a sketch of a promising new approach. Filling in the details and making it viable will present a ton of challenges – as is clear just from a glance at the enormous differences between fluorochemical markets in the 1990’s and 2000’s and fossil-fuel markets today. I see three challenges as biggest, which are quite tightly linked to each other. First, if the proposal is first adopted by a highly motivated subset of nations, how can its terms be designed to give others incentives to join, so the system grows, fast enough, toward global or near-global participation? The Protocol succeeded brilliantly on this score, but under such starkly different conditions that it’s not clear the tools of this success can be directly adapted. Second, how can the proposal handle international trade, in fossil fuels and perhaps in fossil-intensive products? The Montreal Protocol included tight trade restrictions on controlled chemicals, mainly as incentives for new countries to join. It also included carefully drawn threats of much more extreme trade restrictions, which many observers argued were not really credible – except that they worked, so their credibility was not actually put to the test, so they must have been sufficiently credible. (Yes, there’s a little circularity in that, or perhaps a little magic – Thank you, Tom Schelling, we miss you.). But the trade at issue was vastly smaller and simpler than global trade in fossil fuels today. The Commission’s proposal discusses incorporating reciprocal recognition of climate policies into trade measures. But it does not specify how to design accompanying trade measures that would be feasible, enforceable (or sufficiently credible as threats), and not unjustly obstruct development. And that of course is the third linked challenge: differentiating the commitments and trade measures in a way that is compatible with development needs, acceptably equitable, and still achieves the targeted global cuts.

An additional big challenge, less linked to the others, concerns administrative capacity and scale. The Montreal essential-use process represented an enormous effort. Its workload was eased by the similarity of many uses and alternatives across the world – although these were often similar but not identical, especially once the Protocol had to deal with methyl bromide, an ozone-depleting chemical used in agriculture. Fossil uses are vastly larger and more diverse, although the same few, relatively homogeneous uses are repeatedly proposed as hardest to cut: e.g., some transport modes (especially aviation) and some industrial processes (steel, cement, a few others). And even for these, there is vigorous research underway to innovate around the need for fossil fuels. It’s not beyond imagining that an adapted essential-use process could make sound technical judgments about uses and alternatives, even at the needed volume. The scale, stakes, and incentives for multiple actors to tweak the process to their advantage will be serious challenges: but we won’t know how serious, or how they might be surmounted, until someone does the work to try to design a viable process.

These challenges are complex and severe. Some may be insurmountable and make the Commission’s proposal ultimately unworkable. But this is not obvious a priori. The work needs to be done, with the right mix of extreme ambition, creativity, and analytic rigor.

I hope I’ve persuaded you that the Commission’s proposal is constructively radical, in that sweet spot where what looks initially outrageous in fact merits a close look, and might turn out to be workable, in whole or in part – and to move the domain of the possible. As a proposal for a concrete, high-impact, coordinated action adopted by multiple states, it does sit rather awkwardly with the Paris process. This does not mean it’s incompatible with Paris, of course. Stronger actions like this could be coordinated under the Paris umbrella, so long as the leading nations willing to move get to do so and adopt elements to induce others to follow, without being held back by lowest-common-denominator consensus requirements that in effect give vetoes to opponents of strong action. But it is rather culturally incompatible with the process-heavy weak tea that the Paris process has actually delivered thus far.

All in, the most puzzling thing about this Commission proposal is that no one seems to have noticed its radicalism. With a couple of notable exceptions, initial coverage and reaction to the Commission has mainly focused on their discussion of SRM – which is a more obvious advance in the Commission’s work, and which I will discuss in my next post. The most critical reactions to the Commission have, unsurprisingly, focused exclusively on its discussion of SRM. Strangely, these critical reactions all state that deep emissions cuts are the first essential climate response — an observation with which the Commission report obviously agrees. But they also advance the familiar argument that talking about SRM can be a cover or excuse for weakness on mitigation – a point which is also carefully made in the Commission report — while seeming not to notice the radical ambition of the Commission’s recommendations on mitigation. Perhaps this recommendation will be a sleeper, which does have a transformative impact but takes a while to build up to it. I hope so. Go back, give it a close read, and see what you think.

Pt. 3, The Overshoot Commission Addresses Geoengineering

The Commission tries to make it OK to talk about – not do – solar geoengineering. Its report proposes a moratorium, coupled with efforts to carefully build knowledge.

Legal Planet, by Ted Parson, September 26, 2023

In this, my third post on the recently released report of the Climate Overshoot Commission, I’ll discuss their treatment of the most challenging and controversial part of their mandate, Solar Geoengineering or Solar Radiation Modification (SRM). As I noted in my introductory post on the Commission, I served as an advisor to the Secretariat and my students in the UCLA International Climate Law and Policy Clinic provided research and analytic support to the Secretariat. The commentary and discussion I’m posting are my own views, not those of the Commission.

As noted previously, the bedrock of the Commission’s charge was to take the prospect of significant climate overshoot and the associated risks seriously – which other high-level international climate bodies have not – and to think through how serious consideration of that risk changes how you think about all climate responses. Taking these risks seriously requires a willingness to at least consider extreme or radical responses, rather than double down on the same responses you were already pushing. This requires confronting potentially promising approaches that pose real challenges and difficulties – that people have been afraid to look at, that require a leap of imagination, that popular wisdom says are impossible – including responses you wish you didn’t have to consider, but which honest clear-eyed reflection says you have to. In my last post I discussed the Commission’s remarkably radical – and challenging – headline recommendation on mitigation, a global phaseout of fossil fuels. But no part of their mandate or report matches this description of “stuff you wish you didn’t have to think about, but realize you must” better than SRM. [Emph. added by BenIndy.] This is where the Commission faced its greatest challenges, where its clear-eyed view of the risks of overshoot was most strongly put to the test. In my view, they met the challenge very well.

The Commission approached SRM with great hesitation, reflecting their recognition of the top priority that must be given to mitigation and the significant new risks and uncertainties presented by SRM. They expressed particular caution, appropriately, against letting consideration of SRM be a distraction from mitigation and other responses, or an excuse for not making extreme efforts on them. The Commission summarized their complete set of proposals as a “CARE Agenda” for reducing risks from overshoot: Cut emissions; Adapt; Remove; and Explore. Solar geoengineering falls under “Explore,” and there’s a reason it comes last. But the Commission also recognized that under conditions of substantial overshoot, there could soon be demands to use SRM, and that under some conditions using it may be better – for human welfare, especially the most vulnerable, and for non-human ecosystems – than not using it. Both possibilities – that there might be proposals to use it, and that doing so might be on balance beneficial – imply a need to learn more, by doing research and discussing governance needs and possibilities.

That the research done thus far – notwithstanding its uncertainties and limits, and the inability of research alone to resolve governance challenges – has consistently shown the possibility that SRM interventions might be broadly beneficial, especially for the most vulnerable regions, provides additional support for the Commission’s courageous decision to go where other bodies have been afraid to, and take a serious, careful, critical look. Recognizing the contentious arguments around SRM – and the acute tension it presents between potential benefits and harms, and associate deep uncertainties – they presented a carefully integrated and balanced set of recommendations. Considered together, as they must be, these represent real progress.

First, they call for a moratorium on any large-scale SRM interventions. [Emph. added by BenIndy.] The proposal is that governments adopt the moratorium voluntarily, encouraging others also to adopt it by working with other governments directly and through multilateral institutions. This bottom-up approach aims to make adoption spread fast, avoiding the delay and potential rigidity of formal legal negotiations.

Moratoria vary widely in their specifics, and these matter – most importantly, what activities are covered by the moratorium. In the Commission’s carefully crafted language, the moratorium would cover any SRM activity of such scale and intensity that it would present a risk of significant transboundary harm. This language invokes the foundational “no-harm” principle of customary international environmental law, first articulated in the 1941 Trail Smelter arbitration and subsequently re-affirmed in multiple international treaties, declarations, and tribunals. It is thus consistent with large body of prior international law.

The moratorium language is carefully crafted to avoid loopholes. Like the “no-harm” principle generally, it would apply to harms not just to the environments of other states, but also to areas beyond national jurisdiction such as the High seas and Antarctica. And it would apply to any activity above that threshold. [Emph. added by BenIndy.] Adopting states would apply it to their own actions, those done on their territory or under their control, and those done by their citizens or enterprises, even if conducted outside their territory. Recognizing that for SRM there is a blurry boundary between research at large enough scale and operational deployment, the moratorium applies to all activities above the threshold, regardless of purpose: in other words, you don’t get to evade the moratorium by calling the large-scale intervention you are proposing research, not deployment.

The one way in which the moratorium proposal is less restrictive than some proponents of an SRM moratorium would prefer is that the “risk of significant transboundary harm” threshold is quite high. By requiring both “transboundary harm” and “significance,” it would not bar all activities with minimally detectable transboundary effects – which is a moving target in any case, changing as detection capability advances. It would apply only to activities causing material harm, not activities deemed objectionable for symbolic or other non-material reasons. It would not bar all outdoor SRM experiments – of which all now contemplated are many orders of magnitude below the moratorium threshold. At the same time, nothing in the Commission’s recommendations would obstruct states from enacting tighter restrictions if they wish.

The Commission does not state specific recommendations for conditions to end the moratorium, but instead invokes two widely stated pre-conditions for large-scale interventions: enough knowledge from research to support informed decision-making; and an adequate framework to govern proposed interventions. [Emph. added by BenIndy.] Since the specific knowledge and governance conditions that would meet this standard cannot be codified in advance, this is about as good as you can get. Although some moratoria include explicit time limits, this proposal does not – and arguably could not realistically do so, in view of the uncertain time-scales for both further progression of climate harms, and achievement of the stated scientific and governance requirements.

The Commission’s next two SRM recommendations are strongly linked: substantial expansion of SRM research, and strengthened research governance specific to SRM. [Emph. added by BenIndy.] While recommending a substantial expansion of research, the Commission stresses that this implies no stance either for or against future use. In addition, they correctly note that even a large expansion from present levels would still leave SRM research a tiny fraction of all climate research. Beyond broadly noting that SRM research should aim to advance understanding of its effects on the climate system, the environment, and society, the report does not propose a substantive agenda for research. Although several other bodies have recently done so, the Commission understood that it was a policy body, not a scientific one.

The details that elaborate their recommendation to expand research overlap strongly with their recommendations for stronger governance. For example, they recommend strong international cooperation in research, with particular emphasis on collaborative activities involving and led by scientists from developing nations. Research could be coordinated through international bodies and linked to periodic international scientific reviews and assessments, with several existing organizations identified as possible sites for these functions, including WMO, UNEP, IPCC, GRC, and the Future Earth program.

Beyond these international coordination and assessment processes, the Commission suggests that other research governance needs can be met within existing national regulatory frameworks, with some additional measures to address specific concerns raised about SRM research. These additional measures include enhanced transparency provisions to make many aspects of the aims, methods, funding, and results of research broadly publicly available and understandable; avoiding SRM research being led or funded by private firms, particularly from industries that may have interests in delaying large emissions cuts; and provisions for periodic review and assessment that provide clear mileposts and exit ramps, to resist potential pressures to continue or expand research even if conditions and results do not warrant it.

Within SRM research, the most controversial piece by far has been proposals to do active experiments – which would introduce a little bit of material into the environment and observe what happens. The controversy over these is in some respects puzzling, because all experiments proposed or contemplated, and any associated impacts or risks, are tiny – thousands to billions of times too small to have minimally detectable climate effects beyond the immediate experimental site. One widely criticized experiment – which has been proposed but never done – would spray about 1 kilogram of Sulfur from a balloon floating in the stratosphere. Yet at the same time, these physical impacts are all that distinguishes field experiments from other SRM research – lab, model, or passive observation – that have not attracted similar controversy.

Like the experienced political leaders they are, the Commission simply took the fact of the controversy over field experiments as given, without going into the arguments over whether it makes any sense. On that basis, they recommended a few additional governance provisions specific to field experiments. These are all additional precautionary controls they recommend for this research: there is nothing in their recommendations that would limit a jurisdiction from controlling these more tightly – or even bar them on its territory, as Mexico has expressed an intention to do in response to the sovereignty-offending (but materially trivial) “Make Sunsets” debacle.

First, the Commission recommends that these experiments should not be conducted in jurisdictions that lack effective environmental regulatory regimes – in effect, a caution against researchers shopping for lax jurisdictions where they can cut corners. When experiments are conducted under effective environmental protection regimes, the Commission recommends that the degree of regulatory scrutiny and specific requirements should increase with the contemplated scale of the experiment. Several previous bodies have made similar recommendations, going back to the UK Royal Society report of 2009 and the Asilomar Conference declaration of 2010, but the Commission adds more specifics. In particular, they suggest that the first level of heightened scrutiny specific to SRM experiments – beyond the normal requirement to comply with all applicable environment, safety, and other regulations that apply to any field research – might be aligned with the legal thresholds that trigger requirements for formal Environmental Impact Assessment. In most states, this is some variant of an activity anticipated to have a “significant environmental impact.” In addition to normal EIA procedures, the heightened requirements for experiments above this threshold might include additional levels of scientific review that require demonstrating the value or necessity of the proposed scale of activity, or heightened requirements for transparency and consultation. Within the overall governance regime, if proposed activities pass further specified thresholds beyond the initial EIA trigger there could be additional requirements. These might include, for example, engagement in international coordination or harmonization processes, partnership with developing-country researchers or research institutions, or support for broader knowledge-building or governance development activities.

Finally, in parallel with its calls for expanded research and research governance, the Commission also recommends broad consultations and dialogs on the novel and severe governance challenges SRM will pose, particular if there are calls to use it. [Emph. added by BenIndy.] In effect, the Commission recommends that the intensive process it itself has gone through — of education, consideration of still uncertain but potential large benefits and risks, and deliberation over responsible choices in pursuit of a safer and more equitable world – be replicated and extended, with diverse participation, in community, domestic, and international settings. In view of the deep uncertainty that permeates what will, can, or should happen – on climate change overall and on SRM’s role within it, if any – they stress that these consultations should not pursue early policy or legal action, but should be exploratory and informative, aiming to build knowledge, develop creative ideas and insights, and develop norms and trust.

Overall, the Commission’s discussion of SRM is an impressive piece of work. Its recommendations form a coherent whole that presents a comprehensive, reasoned, and careful approach – an approach that offers measured exploration of these high-stakes responses to build knowledge and capacity to address present and future challenges, coupled with measures to limit associated risks. The pieces work together to promote growth in knowledge and capacity while also addressing the concerns that have been raised about SRM. The recommendation for expanded research is coupled with calls for research governance measures that address the most widely identified concerns – seriously and substantively, while not claiming to deliver unattainable certainty – while still letting research proceed. The specific recommendations for more careful scrutiny of field experiments respond seriously to the fact of strong concerns about these – without relying on arguments that the direct environmental effects of these are trivial, which have clearly not assuaged the concerns. The call for periodic scientific assessments and reviews, and built-in mileposts to re-assess research programs, limit risks of unreasoning continuance or expansion toward deployment – variously analogized as lock-in or slippery-slopes. This applies even more strongly to the call for a moratorium, which by reducing alarm that someone might be about to pursue a large-scale intervention, can also allow space for research to better understand SRM’s promise and risks, and for deliberations on how to control these. One of the most consistent objections to SRM research has been the expectation that research programs would expand thoughtlessly into full-scale deployment, even if conditions of knowledge and governance capacity needed to make that advisable are not present. The proposed moratorium would provide some assurance against this scenario, certainly against a hasty or impetuous move that way.

In one sense, the Commission’s recommendations on SRM are not radical or surprising. Their calls for linked research expansion and additional research governance are similar to proposal advanced by several bodies, notably the UNEP Expert Group report in February 2023, as well as two recent widely circulated scientists’ open letters. But they represent an important step forward – both because of important new elements that have not previously been stated together, such as linking the research and research governance recommendations with the carefully crafted moratorium; and because of the politically expert character, the global reach, and the stature of the Commission – which moreover approached this issue as relative newcomers, without preconceptions.

So, what happens now? I can envision two possibilities. First, the recommendation for a moratorium is likely to attract significant attention – as early press reports and other reactions to the Commission suggest. I predict there may be multiple proposals from governments in international settings – including major upcoming events such as COP28 in December and the sixth UNEA next March – to push such a moratorium. I also predict substantial conflict and confusion, some of it intentional, over what such a Moratorium would mean – in particular over what it would actually cover. Sophisticated commentators on international affairs will understand what the Commission intends with its moratorium, and the rationale for a moratorium with such a scope. Opponents of researching or discussing SRM, some of whom have already weighed in in response to the Commission, are likely to support the idea of a moratorium in principle, but push for one with much broader scope, possibly including all field experiments no matter how small.

Second, proposals for expanded and more systematically directed SRM research are coming forward from many quarters. But long-standing concerns about whether and how additional research governance is needed, and discussions over how to concretely meet these needs, have made little progress. New funding proposals will increase the need for these and intensify the associated controversies. Given the Commission’s stature, global diversity, and prominence, I expect its balanced approach, and promising but incomplete specification of particulars, to be highly influential in shaping these debates. The debates will have to continue in other fora, however, which incorporate scientific, policy, civil-society, citizen, and research sponsor views.