Global threats to health in the 21st century

Dr. Christopher Murray, Director of IHME and co-chair of the Lancet Commission on 21st Century Global Threats to Health, discusses the threats most likely to shape human health through 2100. We talk with him about why obesity and low educational attainment carry such large burdens, why sub-Saharan Africa bears a disproportionate share of risks created elsewhere, and what leaders outside the health sector can do now.

• Learn more about the Commission
• Read the Commission's report published in The Lancet
• Watch the launch event at the World Health Summit
• Contextualize the threats to health through the new data visualization tool

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Transcript

Rhonda Stewart: Welcome to Global Health Insights, a podcast from IHME, the Institute for Health Metrics and Evaluation. I’m Rhonda Stewart.

In this episode, we’ll hear from Dr. Chris Murray, Director of IHME and Co-Chair of the Lancet Commission on 21st Century Global Threats to Health. The Commission assessed threats to health over a 75-year horizon from 2025 to 2100 and identified 17 catastrophic threats, including two with extinction potential: malicious use of AI and nuclear conflict.

Rather than focusing on worst-case scenarios, the Commission measured each threat’s amenable burden, the difference in healthy years of life between a plausible best and plausible worst future. The analysis is not a policy ranking, but demonstrates the interconnected nature of these threats.

We cover why sub-Saharan Africa bears a disproportionate share of risks, what finance ministers, business leaders, and security officials should take from the report, and how a recurring monitor could keep these threats on the agenda between crises.

Chris, tell us why this Commission, and why now? Given things like Ebola outbreaks, major geopolitical conflict, cuts to development aid, and how powerful AI has grown, why create a 75-year view of threats to health?

Dr. Christopher Murray: When we started the Commission three-plus years ago, we all had in mind three big threats. One was very long-term climate change, where in the analyses around the effects of emissions, the largest impacts of emissions actually happen in the next century. So to deal with a threat like climate change, you really need a long-term perspective to fully capture its impact.

We had conflict in Ukraine, and we had just come out of a pandemic – COVID, of course – and COVID is another example, or pandemics are another example, where a long-term view is necessary because we can’t know when the next pandemic will be. But we have increasing confidence, when you take the long-term view, that there will be another pandemic, or several of them. And so the long-term view is critical for some of the threats that we need to manage. And if you just look in the short term, you’re going to miss some of the biggest impacts that’ll be out there.

And so that was part of our motivation, trying to get the right time frame for thinking to help governments, the global community, think about these threats. And so we ended up with the 75-year view.

Rhonda Stewart: And in addition to that long-term time horizon, one of the other points made very powerfully in the analysis is the need to address these catastrophic threats simultaneously, not to focus on one at a time. Tell us why that’s so important.

Dr. Christopher Murray: I think we’ve become very familiar with single-issue groups, whether scientific or advocacy focused, that bring to bear a lot of energy and focus on one issue, let’s say conflict or climate change.

But if we just go about looking at threats one at a time, we’re going to miss the fact that there are a lot of threats that we have to manage. It’s not just two or three, it’s many. And in our case, we argue for 17 and that there are common strategies that can be used to tackle multiple threats at the same time.

And so the one-by-one strategy really can give us almost a false sense of security. If we put all of our eggs in the basket of dealing with one issue, we’ll be okay. But we have to live with the reality that there are many challenges that the global community and national governments have to face.

Rhonda Stewart: Along with the interconnected nature of the threats, the analysis also measures threats in a different way, and the Commission explores the threats by amenable burden, the gap between a plausible best and a plausible worst future. Can you break that down for us and help people understand what that means?

Dr. Christopher Murray: Yeah, we spent a lot of time thinking about and debating the pitfalls of forecasting, because of the 75-year time horizon, which is necessary because of some of the threats that are changing slowly and have their big impacts in the future.

You know, think climate change. We depend very much on the forecasts or the scenarios being reasonable. But we know from the history of forecasting that when your forecast can alter policy priorities, then you are in the territory that’s sometimes called reflexivity or self-defeating or self-fulfilling forecasts. Lots of names in different fields, but a well understood problem. And our solution to this was not to say we have a crystal ball and can predict how governments will respond, and this is the pathway of the future for sure, but rather that we can do a better job if we bound the range of possible futures by using empirical approaches to say what’s the plausibly worst that can happen? And plausibly best.

And it’s that zone that we can end up influencing where we land. And the difference between plausible best and worst we call amenable, or amenable burden. And the plausible part is also really key in that thinking and goes into the notion about amenable burden because we can dream up all sorts of scenarios – terrible scenarios, utopian scenarios – but we want to ground our plausible best and worst in what we’ve observed across all countries in the past 35 years or so, where we have good data.

And so we can say look, let’s take the best and the worst we’ve observed across countries and say, what if the whole world moved to that best or worst that we’ve observed? And that gives us an empirically grounded view of plausible best and worst. And that’s been the key lens through which we’ve been looking at the threats into the future.

Rhonda Stewart: The report is very clear that this is not a policy ranking when we look at the different threats. Obesity has the largest amenable burden of the 17 catastrophic threats. And that might be surprising to people that such an everyday condition might appear so high.

Dr. Christopher Murray: I want to reiterate that the main message from the Commission is not necessarily which threat has the biggest amenable burden, but rather there is this multiplicity of really profoundly large catastrophic threats.

Nevertheless, obesity is very large. It is the largest in terms of the estimated amenable burden. And the reason that we do this exercise is the surprises like obesity coming through, which is, until you run the models and map out the trajectory of the possible for the future, we don’t really know whether something that affects many, many people, like obesity, that's getting worse very steadily, will turn out to be super amenable to policy intervention or it’s going to be much smaller.

And so, having done that analysis, what we observe is there are some countries that have held the increase in obesity over the last 35 years to a relatively small amount. Nobody’s brought it down, but some have sort of kept it from going up dramatically. And then there are other places in the world where obesity has really skyrocketed and is on a trajectory of going up and up. When you look at the gap between those and look at the many, many outcomes related to obesity – cancers, heart disease, diabetes – then you end up with a really large potential to improve human health by getting us on the plausible best trajectory for the world.

Rhonda Stewart: Let’s talk about another one of the threats, which is education, and specifically, education as a health lever. So low educational attainment accounts for 16.1 billion years of life lost. More than two-thirds of that falls on sub-Saharan Africa. How does education shape health and even the size of the world’s population?

Dr. Christopher Murray: Well, one of the more robust findings from public health research, both in low-resource settings and high-resource settings, is that educational attainment is a huge driver of child mortality – so that’s the mother’s education – as well as adult mortality. And many people have studied this, and there are many published reviews of the magnitude of this.

And so education, we know, is connected to health. It’s also really strongly related to women’s fertility choices. For every year of completed schooling, it turns out that women end up choosing to have fewer children. And so that is a big driver of fertility and ultimately of world population.

Now in the Commission’s work, the second piece was those plausible trajectories, which is, does education just march along in every country in the same way, or is there a range of countries where they’ve been able to increase educational attainment much faster and others where it’s been much slower? And the answer is yes, there’s a big range.

So if we can get on the pathway of more rapid educational expansion compared to the slower educational expansion, it makes a really big difference. And interestingly, the standout performers on raising particularly girls’ education have been in the Middle East, where they’ve made, essentially over a generation, incredible increases of educational attainment for women with all sorts of benefits that have followed from that.

And then there are places where it's been much slower – some countries in the Sahel where educational attainment has barely moved, particularly for women, over the last 30, 40 years.

So combining those two together, a big range of possible trajectories for education and big connections between education and health outcomes and fertility is why it turns out to be a really important threat. And if we can get the world on the high education attainment trajectory, it will make a really big impact in many domains.

Rhonda Stewart: And of course, we can’t talk about threats without talking about AI, specifically malicious use of AI or AI-enabled bioweapons. That is one of two threats with extinction potential. So explain to us how the Commission approached that risk when there’s so little historical data on this.

Dr. Christopher Murray: So, for two threats, malicious use of AI and nuclear conflict that’s large enough that it can lead to nuclear famine, there we can’t build statistical models. There have only been two nuclear bombs released, in World War II, and there’s not enough data to fit a model on that. Although we did do some interesting modeling using the near-miss literature and for malicious use of AI, saying of course we haven’t observed any major catastrophe yet from AI, so we’ve had to use qualitative approaches for these.

We’ve gone and looked at what experts, domain experts, general citizens, and a group called superforecasters – people with a proven track record of predicting things – and looked at the very wide range of probabilities. And when we started doing this work three years ago and we identified malicious use of AI, there was a group of people who were saying even back then, this is a real threat, particularly using AI to build bioweapons. And, you know, people just laughed at us, to be honest, when we talked to policymakers and other groups and had our various Commission meetings. This was sort of a fringe view three years ago. It is certainly not fringe today, given all the media and attention on AI.

But we’ve seen this as a threat from our reading of what’s out there already and the rapid gains in AI from the beginning of the work of the Commission. And of course, when we get to the end, it figures very prominently in what we’re saying. And I think now that we’re seeing other capabilities of AI so rapidly improve, it’s right to be there at the top of our list as being something with extinction risk potential.

Rhonda Stewart: We often talk in our work about disability-adjusted life years, DALYs, and the importance of health loss as a metric. By 2100, people are expected to spend about 13 years in poor health, which is up from eight years in 1990. So people are living longer lives but more years in poor health. What should health systems and governments be doing now to prepare?

Dr. Christopher Murray: Well, one of the threats is healthy aging for the very reason that there’s a lot of variation across countries. Even if you just take survival as given, there’s a lot of variation in how much time people spend in ill health at each age, particularly the older age groups.

Some of that has to do with some of the risk factor profiles – physical activity and diet. Some of that has to do with classic metabolic risks – high obesity or smoking. And some of it has to do with social policy. Is it easy to exercise? Is the government doing urban planning to make it easier for people to have a healthy diet, etc. So there’s an interface there between public policy as well as managing some of the key risks. And over time, we may well see therapies that can help as well maintain that sort of healthier trajectory.

But the data are very clear that we’re on the wrong track right now. We’re on the track where we are making more progress on reducing mortality and not reducing particularly the things that get worse with age – musculoskeletal disorders, vision, hearing, mobility, a number of other factors that generally get worse as you get older. And as we live into those age groups, we will end up with more people with needs that the health system will have to tackle unless we change the trajectory toward a healthier trajectory with age.

Rhonda Stewart: So many of these threats, from inequality to conflict to low education, start outside of health. What does the Commission want finance ministers, business leaders, security officials, and other decision-makers to take away from the report?

Dr. Christopher Murray: You know, we had on our Commission Mario Monti, former Prime Minister of Italy, who argued from our first meeting that we should be very worried, in terms of threats, about two views, and we need to counteract those views.

One was short-termism, not seeing the long run, not seeing these threats that can evolve like climate over many, many decades – and localism, just caring about your local community and not the rest of the country or the rest of the world.

And the antidote, in his mind and in the conclusions of the Commission, is to bring to the attention of ministers of finance as well as ministers of health and heads of state, this sort of regular assessment of what are the big threats, how are they evolving? Are there new threats that have emerged? And that there should be within each government a resourced group whose job it is to anticipate, prevent, and prepare for threats.

And then at the global level, we should continue tracking those threats. And thus the idea – one of our recommendations is a monitor, like the Commission has done, but as an ongoing mechanism to feed into various fora – G20UN, the Munich Security Conference – these empirical findings on threats because they cut across security, economic policy, social policy, health. And that’s the way it should be because it’s a diverse set of problems that impact health, and therefore we need a diverse set of actors to do something about those threats.

Rhonda Stewart: Great. Thanks very much, Chris. Details about the Lancet Commission on 21st Century Threats to Global Health, including the full report and underlying data, can be found at healthdata.org.

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An independent population health research organization based at the University of Washington School of Medicine, the Institute for Health Metrics and Evaluation (IHME) works with collaborators around the world to develop timely, relevant, and scientifically valid evidence that illuminates the state of health everywhere. In making our research available and approachable, we aim to inform health policy and practice in pursuit of our vision: all people living long lives in full health. Learn more about IHME.

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