— You began your career in pure climate science. What drew you towards sustainable development?

Frustration, fundamentally. I had been Head of the IPCC Scientific Assessment Unit and then Director of the Hadley Centre for Climate Change at the UK Met Office. And I became deeply frustrated by a refrain that kept coming up: “If only we got the science right, then everybody would act.” We got the science more and more right — and people didn’t act. So when the opportunity came to set up the Monash Sustainable Development Institute in Australia, I took it. That was in 2007, and I directed it for the next ten years.

— Take us back to 2012, when the conversation about what would succeed the Millennium Development Goals was just beginning. What was the atmosphere?

The challenge was crystallised in a single UN mandate — one sentence, literally. I’ll read it out, because it puts everything into focus. The goals were to be “action-oriented, concise, easy to communicate, limited in number, aspirational, global in nature, and universally applicable to all countries, whilst taking into account different national realities, capacities, and levels of development, and respecting national policies and priorities.” And you expected 200 countries to come together and agree on something like that. It was mind-boggling in its complexity. The prevailing mood was: surely this is impossible. So I brought together a group of leading scientific colleagues, and we published a paper in Nature in 2013 — “Sustainable Development Goals for People and Planet” — proposing a set of goals for the first time. We knew they wouldn’t be the actual SDGs. But we wanted to plant a flag and say: look, this can be done.

— What is your honest assessment of what the SDGs have achieved, and where they have fallen short?

What they have achieved above all is a complete change in the narrative. They moved us from the Wild West to a common sense of purpose. Before the SDGs, everyone had the answer: if only we educated everyone, everything would be fine. If only we solved climate change. If only we ended poverty and hunger. The list was endless, and everyone was pulling in a different direction. The SDGs brought order to that chaos. Yes, they are flawed. Yes, they are a political compromise. But for the first time, there was an agreement: this is where we are going, and if we get there, it will be better than where we are now. Large philanthropic organisations bought into it, large businesses, some governments, some international development agencies — the landscape has fundamentally changed. Of course, many of the goals will not be met. Some for very understandable reasons, some less so. COVID, the global cost-of-living crisis, the conflicts in Ukraine and the Middle East — nobody could have foreseen the scale of those obstacles. But at least, for the first time, we had a sense of direction.

— The political context has shifted dramatically since 2015. Multilateralism is under pressure, and nationalism is on the rise. How will this shape what comes after 2030?

It cannot help but be fundamentally affected. In 2015, I don’t think we realised what a window we had — a world that was genuinely open to this kind of discussion. That world is now much more closed. Borders have tightened. Countries have become far more insular in their outlook. Trust in international organisations and global agreements has diminished considerably. We are in a very, very different landscape. And my own view is that if we open up a complete overhaul — if we start again from scratch— there is a very high risk that we will end up with nothing at all. That is not something I particularly like. But it is the reality we are in.

— What do you propose concretely for the post-2030 agenda?

Retain the SDGs in their current form and use them as the foundation for what we build after 2030. Rather than discarding them and starting over. There is a great deal to be done: improving implementation, strengthening accountability, deepening engagement, and bringing more people in. And yes, perhaps adding a few things to acknowledge what is missing in the current agenda — culture is almost absent from the SDGs, indigenous peoples are sorely underrepresented, and there is a whole range of issues that are not covered well enough. But to actually unwrap all of that — to open that Pandora’s box — is a risk we would be unwise to take.

— What actually works in holding governments to their global commitments?

Very little, frankly. Self-interest, peer pressure, and the fear of not being re-elected. When governments genuinely see that following through is in their own interest — that their country will be on a better path, that their electorate will view them more favourably — things move. But that logic is very hard to sustain when people are focused on whether they can afford to put food on the table or find somewhere for their family to live. Those concerns take priority, and quite understandably so.

— There is a real tension between the complexity of the science and the need for something simple enough to be politically negotiable. Have the SDGs struck the right balance?

The mandate said, “limited in number, easy to communicate.” One can debate whether 17 goals are really limited in number. But think of the sheer magnitude of what you are trying to cover — the entire future direction of the human race. Getting that down to 17 goals and 175 targets is not bad going, not bad at all. What concerns me more is that we have no credible mechanism for knowing where we actually stand. The IPCC is the model here: every six or seven years, the global scientific and policy community comes together and honestly assesses — this is where we are, this is what we need to focus on. That has been seriously lacking in the SDG agenda. The High-Level Political Forum exists, the Global Sustainable Development Review exists — but the latter was never remotely resourced to fulfil that role. And the Voluntary National Reviews? I always liken those to students marking their own homework. They let you see what they want you to see; they don’t necessarily let you see what they don’t want you to see. There is currently no independent assessment of where we are with the SDGs. That is one of the things the post-2030 agenda must address.

— If you could protect just one thing as the conversation about what comes next unfolds, what would it be?

Don’t lose the SDGs. They are flawed — I could go on at length about the fact that culture is almost entirely missing, that indigenous peoples are sorely underrepresented, a whole range of things that the SDGs don’t cover well enough. However, they exist. They agreed. The political climate today is very different. Don’t throw them out unless you can be 100% certain that what you are going to come out with will be better. And I do not currently see how we can have that assurance.

— Any final message for those working in this space?

I once gave a talk to the international development community and opened by saying, “You are no longer the international development community. You are the sustainable development community, whether you like it or not.” It wasn’t particularly well-received. But the point was simple: nobody can work within their own silo any more. You cannot just work on climate change, or poverty, or decent jobs, or education, or health in isolation. You have to look at how what you are doing interacts with the entire sustainable development agenda — because all of those goals, all of those targets, are interlinked. I mapped a 175-by-175 matrix of SDG target interactions, and I could put something in every single box. And most of those interactions are positive: what is good for education is good for health; what is good for gender equality is good for the environment. But it makes your life more difficult, because you can no longer simply talk to people who speak your language and understand all your acronyms.

I often give the example of a health NGO that was about to build a hospital in Africa. They had looked at SDG 3 on health and were satisfied. I asked whether they had looked at the other SDGs. They had not. Where would the food served in the hospital come from — local, sustainable sources? What about energy — had they considered renewables? Would the jobs created be decent jobs, recruited from the local community? Where would all the hospital waste go? By the end of the conversation, we had linked what they were doing to every single one of the other SDGs. And he said: “You have just made my project sixteen times more difficult.” But also sixteen times better.