Managing the Risks from an Increasingly Likely Overshoot of 1.5°C – The role (if any) of solar radiation modification 

By Janos Pasztor

I write this blog having just arrived in Islamabad, Pakistan’s capital city, part of an intensive period of engagement with senior government officials that my colleagues at C2G and I are undertaking.  It is hard to overstate the degree of devastation this country has suffered after heavy monsoons earlier this year left one third of the country under water, millions homeless and affected 33 million people, half of them children.  

In our meetings with government representatives in different parts of the world, it is clear they see climate change as far more than just an environmental issue, but a powerful threat to their people’s health, livelihoods, security and in many cases survival.   

In this context, the agreement at COP27 to create a loss and damage facility represents a significant step forward for countries like Pakistan who are already suffering grievously from the impacts of climate change. However, the real test will be how this facility will operate, and how much funding will be provided, in addition to the resources needed – and not yet delivered – for massive adaptation and mitigation needs. 

As COP27 also showed, serious progress in reducing emissions remains elusive. UNEP’s Emissions Gap report, issued before negotiators gathered in Sharm El-Sheik, starkly noted there is no credible plan for 1.5°C in place.  To date, the world has not set in motion the speed and scale of transformation needed.   

Everywhere my colleagues and I have been recently, and this includes capital cities on all continents, senior policymakers have told us they are deeply worried about the climate impacts at the current level of average global warming, which is about 1.2°C. I cannot help but think what the world will look like if 1.5°C of warming is exceeded, which the IPCC’s latest reports say is more likely than not, even under the most ambitious emission pathways. How long those above 1.5°C temperatures might last, and how hot the world might get before temperatures then cooled down, depends on how quickly we act to reduce emissions and remove excess carbon from the atmosphere.  

Overshoot and implications for SRM governance

 As C2G has been saying for some time, governments and non-state actors need to seriously and urgently grapple with the fact that our planet will get warmer in our lifetime, jeopardizing the Sustainable Development Goals (SDGs), and having serious impacts on global security. In this context, governments will have to reduce the risk of overshoot by continuing to prioritize deep and rapid emissions reductions, combined with removals.

In addition, as temperatures continue to rise, they will need to increase measures to adapt to the impacts of warming, and resources to address losses and damages already taking place. Clearly, the more the world does to reduce the risks of overshoot, the less we will need to deal with the risks from overshoot later.

Clearly, the more the world does to reduce the risks of overshoot, the less we will need to deal with the risks from overshoot later

According to the UNEP Emissions Gap Report, current trends indicate the world is on track for 2.4 to 2.8°C of warming by the end of this century. In light of the increasing likelihood that the world fails to limit warming to 1.5°C, interest is growing in considering solar radiation modification (SRM), which could temporarily limit warming by reflecting sunlight back into space and thus help minimize some of the risks arising from overshoot Policymakers will soon be faced with a serious dilemma: how should decisions on the potential research, testing and even use of these climate-altering techniques be made, by whom, and through what process? 

This challenge is complicated by the fact that, as the IPCC acknowledges, SRM may temporarily reduce the global average temperature, but it poses new risks of its own, some of which can be quantified and others that cannot. In the eyes of many, moral hazard – the assumption that deploying SRM might serve as a distraction from doing what we know we have to do  regardless – as priority to address the root cause of the climate crisis by reducing emissions and removing excess carbon from the atmosphere – is perhaps the most troublesome.  

Could SRM, if it proves technically feasible in the next decade or so, be a desirable supplement to these measures? And if so, what are the potential benefits and risks of going down this path, as opposed to not doing so and overshooting 1.5 temporarily? Importantly, the benefits and risks are not only environmental, including impacts on irreversible climate tipping points, but also those affecting human health, food security, biodiversity, and many other issues.  

Of course, these are extremely difficult choices to make, and there is no shortage of other crises – from pandemics to the war in Ukraine to food insecurity in many developing countries – that policymakers are facing. Multilateralism is also under severe strain.  However, current policy makers have the responsibility to take decisions that consider the possible options to address the risks of and the risks from overshoot without undermining actions and strategies to address the root cause of the climate crisis: to reduce emissions. 

Governance, however, as we at C2G have been saying all along, is more than just governments taking action.  Non-state actors, such as for example civil society organizations (CSOs), academia and the private sector all have roles to play in the wide societal conversations needed, and in many other activities. 

The road ahead next year

Looking at the work ahead of us for 2023, it is clear that we have a full plate. As we have said before, our remaining strategic objective is to catalyse an initial consideration of SRM in the UN General Assembly (UNGA) before the end of 2023. This would be framed within the context of managing the risks from an overheating world in a way that supports better sustainable development outcomes on the one hand, and of the current lack of comprehensive governance on the other.  

Given its universal representation, as well as its ability to consider issues going beyond individual traditional sectors, UNGA is well placed to deliberate transparently on an issue such as SRM.  If ever used, SRM would affect every nation, ecosystem and economy in the world, but not necessarily equally, and would impact nearly all the SDGs – sometimes positively, and sometimes negatively, though in ways not yet well understood. Of course, overshooting 1.5°C would also impact the SDGs.    

C2G is not proposing, any particular outcome from an initial consideration by UNGA. Governments could decide upon any number of different outcomes, including agreeing that more time is needed before undertaking any significant discussion in the UNGA; beginning reflections on  conditions for considering emerging SRM techniques; asking the UN Secretary-General to keep these techniques under review; requesting the UN Environment Programme to conduct assessments of the risks and benefits, as well as governance challenges and opportunities of SRM; or mandating a working group or high-level panel to consider and report on these issues. Or it could be some  combination of these or other options.  

In any event, sparking a consideration of SRM in UNGA would be an important first step toward creating an environment for learning and understanding about SRM – important basis for effective multilateral governance.   

While C2G’s strategic objective remains UNGA, we have been clear that actions by other intergovernmental bodies and non-state actors can contribute indirectly or even directly to UN Member States taking up these issues in UNGA.  In that regard we have continued to engage with many such processes – sometimes on request, sometimes at our own initiative.  Some entities in the UN system (e.g., UNGA, UNESCO, UNHCR, WMO, UNEA/UNEP, Montreal Protocol, IPCC) are undertaking activities or have taken decisions that address SRM.   

Our strategic objective has and will continue to take a great deal of behind-the-scenes diplomatic work, much of it in capitals of some four dozen countries, where decisions are made and then communicated to diplomats working at UN missions in New York and elsewhere. This will also take continued and increasingly intensified outreach with UN missions in New York, and with various groups of diplomats interested in exploring these difficult issues. 

My colleagues and I will be on the road again starting early in 2023. As we meet privately with senior government representatives, we often hear the same refrain, especially – but not only – in the Global South, where there are fewer resources to build climate resilience: we are already experiencing serious climate impacts; how will we manage if the temperature continues to climb, and storms, droughts, sea level rise and extreme heat inflict further suffering on our people

These policymakers and their advisors are increasingly aware that we are charting unknown territory as the likelihood of overshooting the 1.5°C goal becomes more likely. Whether the world could or should use – or not use – approaches such as SRM to manage the risks of overshoot is a vexing question with profound implications for every country. We believe it is time for that discussion to start next September at UNGA. 

These policymakers and their advisors are increasingly aware that we are charting unknown territory as the likelihood of overshooting the 1.5°C goal becomes more likely. Whether the world could or should use – or not use – approaches such as SRM to manage the risks of overshoot is a vexing question with profound implications for every country.

Staying true to our mission:  C2G closes its doors end of 2023 

And yet even as we work toward this goal, we are acutely aware of a pledge we made to our funders and partners when we began C2G in 2016: this initiative would not continue in perpetuity but stay true to its mission to serve as a catalyst to encourage others to act.   

Since 2016, we have met with senior officials from more than 50 governments key to the global climate agenda, from G20 actors to small island Pacific nations and a wide range of least developed countries.  We have also spoken with more than 50 intergovernmental actors and over three times that number of CSOs and think tanks that advise global and national policymakers, and which are important actors in the broader governance processes necessary in societies at national and global levels. We are thankful to the more than 70 international experts from IPCC and all around the world as well as senior policy makers that have engaged in C2GLearn, C2GTalk and C2GDiscuss events – all available on our website.  

Through bilateral meetings, workshops, panel discussions, regional meetings, policy briefs and reports we have issued, we are confident we have catalysed policymakers, their advisors, experts and representatives of non-state actors from all continents, to learn about SRM and its governance, a topic most of them had never heard of before C2G brought it to their attention.  

Moreover, we have encouraged them to hold discussions with their peers, and to begin to form their views on SRM and what role it may – or may not – play in a world that surpasses the Paris temperature goals. And in that context, we have urged governments to explore how SRM might be governed multilaterally to minimize risks – both known and unknown – that could arise from testing or deployment of SRM.  

The results of our outreach ultimately depend on these actors themselves and what they decide to do.  But by the close of next year, our mission will be finished. We will have done all an initiative like ours can. More of the same actions by C2G will not advance the governance of SRM.  It is increasingly time for other actors to pick up the baton – governments of course, as well as non-state actors, to advocate for or against use of SRM as part of our climate response.   

Beyond 2023: the post-C2G transition 

Based on our experience to date, we think intergovernmental bodies, preferably in the UN system, are best placed to carry forward much of our impartial, evidence-based work. C2G has met repeatedly with senior representatives of relevant UN entities, and hope that they will take on this critically important role, recognizing that they need guidance and mandates from governments for this. 

C2G has also engaged with climate and development CSOs around the world. Our goal has always been the same:  to raise awareness about governance needs of SRM (and earlier of CDR); provide impartial, evidence-based learning materials, all publicly available on our website; and convene actors to discuss these issues from different perspectives. We believe the time has now come for CSOs to increasingly engage and participate in global discussions on this issue.  No doubt there will be a range of views, and this is to be welcomed.  

Some actors may be strenuously against SRM based on their own values and ideologies, and call for an outright ban or a moratorium. Others may argue that SRM research is definitely needed and should be pursued – though stop short of favouring deployment. Yet others feel that one or another type of SRM needs to be part of the world’s climate response.  Different actors engage for or against SRM from climate equity, health, security or other perspectives.  Some contend that actors from the Global South need to be increasingly participating in research and eventually in decision-making processes. 

With these thoughts written down, I am now ready for a few days of intensive meetings with representatives of government and non-state actors in Pakistan, to hear their thoughts about these complex issues, and what follow-up actions they plan to undertake after these meetings at national and international levels. 

As 2022 draws to a close, I would like to thank you, our readers, and most importantly the individuals and institutions that have engaged with C2G on these difficult but important issues.  My colleagues and I look forward to a busy and productive final year for our C2G Initiative.   

Until then, all best wishes for the soon to be with us 2023. 


Janos Pasztor 

Geneva-Islamabad, 12 December 2022 

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