Interview by Dr. Joshua Wells
About Prof. Darrel Moellendorf
Prof. Darrel Moellendorf is a political theorist and an environmental, moral, and political philosopher. His philosophical research is driven by real-world problems affecting our lives and the world. With broad interests in Political Theory and Philosophy, he began his professional journey as a Hegel scholar, focusing on Hegel’s philosophy of mind. He has defended an egalitarian form of cosmopolitanism within global justice debates and developed a theory on just war, Jus ex Bello, which centers on the morality of ending wars.
He is currently engaged in three research projects: 1) A philosophical memoir, The Examined Illness: The Good Life at the Edge of Life, reflecting on his experience with a rare form of blood cancer, set for completion in 2024 and publication in 2025 by Intellect Books. 2) An interdisciplinary research project titled Making Hope, in collaboration with two empirically focused colleagues, which examines whether central conceptual questions in the moral psychology of hope can be adequately addressed through empirical study. 3) A book manuscript in political theory and environmental philosophy, tentatively titled Another Anthropocene is Possible: Prosperity within Planetary Boundaries.
In his writing, he strives for clarity and analytical rigor, with careful attention to argumentative structure and evidentiary support, and he encourages the students he supervises to adopt the same approach.
Do you remember when you first became aware of climate change as a problem? And when you first started feeling concerned about it?

Yes, I do remember. It was around 1999 when I was working on my book Cosmopolitan Justice, which focuses on global justice. During that time, I came across the works of philosophers Henry Shue and Dale Jamieson, who had recently published some of the earliest pieces on climate change.
Their writings, combined with my reflections on global justice and cooperation, made me aware of the issue. However, back then, it still felt like a distant problem, something that wouldn’t directly or immediately impact our lives.
Do you recall when your interest in climate change shifted from an academic concern to a more urgent concern that truly demanded your attention?
Yes, I think even back then, I considered it serious and worthy of my time, but I believed we had plenty of time to address it. I thought it was more likely to impact my children’s lives rather than mine. I didn’t expect it to produce significant harmful effects within my lifetime. So, from the moment I became aware of it, I recognised it as a serious issue, but not necessarily as an immediate or pressing one.
You have researched many issues related to climate change and one interesting topic is your defence of the UNFCCC. It could be easy for people to be sceptical and say that the UNFCCC is ineffective, particularly considering recent warming trends and the likelihood that we may miss the 1.5°C target set by the Paris Agreement. How would you respond to someone sceptical of the UNFCCC’s value?
There are indeed valid reasons to be sceptical, and I think there’s some truth to the concerns you’ve raised. The UNFCCC has not fully lived up to the task so far. Given the record warming we are experiencing, it’s clear it hasn’t met the expectations many had hoped it would. Serious critiques of the institution and its processes are not only warranted, but necessary.
When I defend the norms of the UNFCCC, it’s partly within a philosophical debate about the role of political philosophy in public discussions. I believe philosophers should engage in the ongoing political discussion, contributing to the democratic process of setting goals. It’s important to consider where the debate currently stands, examine existing norms, and look for ways to advance justice within those frameworks.
I sometimes see philosophers approaching issues of justice in a somewhat abstract way—they identify what they believe to be the right or just solution, then perhaps expect that by presenting this in the literature, the world will recognise the validity of their argument and fall in line. This idea, that philosophers act as ‘philosopher-kings’, is a role I think we should avoid.
In the case of climate change, what struck me early on was that the UNFCCC is not just a technical document, but one that’s rich in normative content. If taken seriously, these norms could guide both deliberation and policy-setting. The norms within the UNFCCC are highly plausible morally and can be philosophically defended. I believe that philosophers should help explain and justify these norms, showing their implications for policy. So, when I defend the norms of the UNFCCC, it’s with the understanding that philosophers should contribute to ongoing public debates about justice. It’s not a claim that existing institutions are adequately fulfilling those norms.
If there is a politician or policymaker reading this, what type of norm would you point out to them to take seriously?

A good example is the right to promote sustainable development, which I believe has a solid and defensible philosophical foundation. I would interpret it as what we, in political and legal philosophy, call a liberty right. Specifically, developing, middle-income, and low-income states have a claim against highly developed or high-income states. This claim asserts that while these countries cooperate to meet the goals of climate change mitigation and adaptation, they should not be hindered in pursuing their national development strategies or their human development aspirations.
To ensure this freedom, there needs to be the right kind of collective agreement—one that not only satisfies the demands of climate change mitigation and adaptation but also allows these countries to pursue their developmental goals. It’s a liberty within a collective process, a process for mutual advantage, which aims to deal with the climate change problem in a just manner.
In addition to this liberty right, there’s also a corresponding duty of responsibility. If we accept that middle- and low-income states have a just claim to pursue their national development agendas, then high-income states have a particular responsibility. They must ensure that climate change mitigation and adaptation are carried out in ways that do not place an undue burden on these less-developed nations. High-income states, given their greater capacities and resources, must take on more responsibility in this collective effort.
What’s interesting about the UNFCCC document itself is the strong commitment to norms, which is evident from the outset. For example, the very identification of “dangerous climate change” is a fundamentally normative concept. Since the objective of preventing dangerous climate change is built into the treaty’s core, the treaty is fundamentally normative.
Justice is sometimes seen as an ideal that philosophers discuss, but not necessarily something that politicians or policymakers can realistically aim for because it’s too demanding. Why should we care about justice?
The famous 20th-century philosopher, John Rawls said that justice is the first virtue of social institutions, much like truth is to assertions. He didn’t mean that justice is the only important thing, but rather that institutions which are fundamentally unjust cannot be considered adequate, except in exceptional or emergency situations.
I believe we must aspire to justice — not only as an ultimate goal, but also in the way we pursue it. While other values such as efficiency, human development, and sustainability are certainly important, many of these, in the end, will also come down to questions of justice. Justice has to be central in our minds when we are discussing policy, particularly on issues as important as climate change.
As we look ahead to COP29, which will focus on climate finance, it’s fair to say previous COP meetings haven’t been very successful in resolving this issue. Could you give us a sense of what a just arrangement might look like in the context of climate finance?
This allows again to discuss the importance of justice.When we think about climate finance, it can often seem like an arcane and technical discussion—one driven by experts, which may not immediately interest those concerned about climate change. But in reality, climate finance is, in many ways, the elephant in the room. The challenge of climate change is something that will only be adequately addressed through international cooperation. States need to come together to reduce and eventually eliminate CO₂ emissions, to cooperate on adapting to climate change, and to address the loss and damage caused by it.
This level of international cooperation is unprecedented, and it’s not clear whether countries are up to the task. Cooperation can only exist if all parties benefit from it, and for this to happen, the terms of cooperation must be fair.
This is where the issue of justice re-enters the discussion. The global energy transition demands massive changes in infrastructure, especially in developing countries. It’s not just about switching energy sources, but also about producing and distributing energy differently, building new capacity, and protecting communities and ecosystems from the impacts of climate change.
All of this requires finance, which is readily available to high-income states but not as accessible to medium- and low-income countries. Finance then is at the heart of the possibility of international cooperation. If low- and medium-income countries are asked to finance this transition at the expense of their own development goals, they are likely to see it as an unfair demand. They could reasonably argue that high-income countries, having already achieved a high level of development, are asking them to make unreasonable sacrifices for the global project. This would no longer feel like genuine cooperation based on fair terms.
Without just and adequate finance, the alternative is more international tension and acrimony. As this tension grows, the goals of climate change mitigation and adaptation become harder to achieve. It’s very concerning then that while the planet continues to warm, cooperation on finance seems increasingly difficult to realise.
More concretely, one of the key proposals emerging from the Paris Agreement is the New Collective Quantified Goal (NCQG), a financial mechanism where high-income states contribute funds to support climate change adaptation and mitigation in medium- and low-income countries. This will be a central issue at COP29.
However, there is scepticism from low- and medium-countries due to past promises. For example, the earlier pledge to provide $100bn per year by 2020 was not fully realised until 2022. Even then, much of the finance was in the form of loans—some low-interest, but still loans—rather than grants, raising concerns about debt burdens on developing nations.
So, heading into COP29, there remains a significant challenge around securing genuine international cooperation on finance. And the success of the collective effort to address climate change—and international cooperation in other areas too—could well depend on a just financial arrangement.
You’ve written about hope, an idea that sounds simple but can be difficult to define, especially in the context of something like climate change. Could you talk about why hope is important in this context?
It’s fair to say that it’s harder than ever to be hopeful about climate change. If you follow the news, it’s clear we’ve been breaking heat records across the globe. The European Climate Agency recently reported that for each of the last 13 months, global average temperatures have been over 1.5°C above pre-industrial levels. While that doesn’t mean we’ve permanently exceeded the 1.5°C goal, it does suggest we’re heading in that direction, and there’s little indication we’ll reverse this in time.
We’re likely to overshoot the 1.5°C target, and even if we later bring temperatures down, that raises further challenges. Adding to the difficulty, many countries are showing insufficient ambition in updating their nationally determined contributions (NDCs) ahead of COP29.
All of this can make it hard to feel hopeful. So, what’s the role of hope in this context? I think it’s crucial to distinguish between hope and wishful thinking. Wishful thinking is often criticised for being unrealistic—it involves desiring things that may never be fulfilled. In contrast, hope involves a sense of real possibility. If there’s no possibility that an aim can be achieved, it’s no longer hope but wishful thinking.
Hope also carries an endorsement of the good we seek to achieve. When we hope for something, we recognise its value. More importantly, hope can be a source of motivation. When we hope for an outcome that is possible, either through our own actions or through collective effort, that hope motivates us to pursue the goal.
This is the danger of losing hope—when hope fades, motivation can too, and the loss of motivation can lead to a self-fulfilling prophecy. If we no longer believe an aim is possible, we stop working towards it, and its non-achievement becomes certain. It’s a vicious circle.
This is why hope is so important in the fight against climate change. It drives action and prevents us from falling into despair. But for hope to remain viable, we must ensure that the path towards our goals is still possible. In this case, that means ensuring the process of international cooperation is fair. If the terms of cooperation aren’t just, there won’t be buy-in from all countries, and the goal becomes even more difficult to achieve. Ultimately, there’s a strong connection between maintaining hope and committing to justice. Justice ensures fairness in cooperation, and fairness keeps the hope for a better future alive. Without justice, we risk losing the very motivation we need to tackle the climate crisis.
It seems I could hope for many things in relation to COP29—justice, fair terms of cooperation, adequate climate finance, or even that key countries show up with the right attitude. What does hope look like when we apply it to COP29?
Ultimately, the core hope for those concerned about climate change is that we are able to limit global warming to a reasonable target—1.5°C being the goal—and that we can adequately protect people from the effects of warming and compensate those who are harmed.
To achieve this, there must be international cooperation based on fair terms. Hope for COP29, then, is tied to the possibility of creating a fair framework for global cooperation.
However, hope in the context of climate change must also involve thinking about what citizens and activists can do. In democratic countries, where people have the political freedom to mobilise, hope becomes about what citizens should demand from their governments. What should be the political aims that motivate them?
In this sense, hope is not just a passive feeling but a motivating force for citizens and activists to pressure their governments to pursue the right goals on the international stage. It’s about translating hope into action—mobilising and making demands that push governments towards the fair and just cooperation needed to address the climate crisis.
Another topic that you have written about is Geoengineering, the idea that you can use science and technology to alter the global temperature, which has long been considered a taboo subject. Do you think this view is still appropriate, or is it time to reconsider, given the shortcomings in our mitigation efforts?

As you suggest, this is a difficult and complex issue. We must carefully consider the context and the consequences of the policy failures we’ve seen so far. As I mentioned earlier, global temperatures have been consistently above 1.5°C over the past 13 months. If we take the 1.5°C goal seriously, then we are entering an overshoot scenario where temperatures exceed the target before we can find ways to bring them back down.
To bring temperatures down after overshooting, we would need a massive commitment to climate change mitigation, which we’ve not demonstrated so far. Additionally, we would likely need technologies for carbon dioxide removal (CDR), or negative emissions technologies, to extract CO₂ from the atmosphere and store it. While there have been promising developments in CDR, they aren’t yet at scale, and we face significant uncertainties regarding costs, feasibility, and the potential impact on other human development goals, such as food production.
If we can’t scale these technologies in time, we may never bring the average temperature back down, with dire consequences. For example, estimates suggest that the difference between warming of 1.5°C and 2°C could mean hundreds of millions of people being trapped in poverty for generations. This half-degree difference is crucial from a human rights and justice perspective.
Within this context, we must reconsider the taboo around geoengineering, specifically stratospheric aerosol injection (SAI). This involves shooting aerosols into the atmosphere to slightly dim the planet by reflecting some of the sun’s radiation back into space.
Given the severe risks of overshooting 1.5°C, I believe geoengineering should not be taboo. Instead, it should be studied and considered carefully, as it might be the only viable option for cooling the planet in the overshoot scenario.
I want to be clear, though—geoengineering is not a cure-all. It could never replace climate change mitigation or carbon dioxide removal. But it could, possibly, serve as a temporary supplement for a few decades, helping to limit warming while we work on longer-term solutions. The risks are significant, so it’s essential to approach this option with caution and ensure thorough research and debate before any large-scale implementation.
Do you think COP meetings are the right forum for geoengineering to be considered eventually?
I think COPs would have to be involved, as any decision on geoengineering would require an international agreement. Currently, there’s no international framework or language to address geoengineering. The role of COPs could be to establish that framework, structure the research, set limits, and regulate any potential actions. COPs could help create the necessary international guidelines to ensure that geoengineering is handled responsibly and ethically.
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