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NHMRC

A conversation with Professor Tony McMichael

droughtHighlights version, 15 May 2008

During the late 1980s it became increasingly clear to Professor McMichael that the emerging evidence of new, global and environmental changes — such as the then-controversial greenhouse effect — posed very real and significant risks to human health. In this conversation, Professor McMichael discusses the challenges he now faces: to understand better how climatic conditions affect human health; to detect the emerging impacts of climate change on health; and to estimate the likely future impact.

Voice-over: Welcome to the National Health and Medical Research Council podcast. Our podcasts aim to keep you in touch with major health and medical research issues, and the people who shape them.

Introduction: Climate change is one of the biggest global issues of our time. But what impact will it have on your health? Professor Tony McMichael is an NHMRC Fellow and one of many scientists who contributed research to the UN’s Intergovernmental Panel on Climate Change, which won a Nobel Prize last year. Here he talks with Dr Mark Bradley about the way climate change can affect our health.

Interviewer: Tony, thanks for joining us today on this NHMRC podcast.

Prof. McMichael: That's a pleasure.

Interviewer: Tony, I wonder if we could start with a bit of a macro view of the issue. Climate change is on everybody's lips at the moment and at the forefront of our minds. But we don't often think about the effect of climate change and the potential this has on the emergence of infectious diseases. So could you just give us a picture of what the problem is that you see emerging.

Prof. McMichael: Well, I think the basic problem, that you've alluded to already, is that we really haven't got the full measure of what the significance, the impacts, of climate change, and indeed the various other global environment changes of which climate change is just part of the syndrome. We haven't got the measure of what they really signify. We've been fretting about the impact on the economy, disruption of economic activity, loss of jobs in some sectors. We worry about the threat to tourism, to physical infrastructure, to iconic species, and those things are all important.

But I think what we haven't done is to realise that now that we've started to disrupt the world's climate system and very many other of the great natural systems that are this planet's life support system, we are actually beginning to change the conditions of life on earth. And that's a big deal. That's what I would regard as the most important aspect of the climate change story. And we're just now starting to realise that as we begin to see that in addition to all the other impacts that climate change has already begun to have, we can see effects on human wellbeing, human health, in some parts of the world, and we're expecting that there'll be many more in the future. It includes infectious diseases as an important part of the story, but it's only part. There will be a whole range of adverse health effects.

Interviewer: Now clearly governments all around the world are concerned and they need to have a response to these emerging issues. What's your take on what governments are trying to do in terms of preparedness scenarios for the emergence of these particular problems?

Prof. McMichael: Well, I should say at the outset that of course the problem is rather wider than infectious diseases. They capture a lot of our attention and we know that they're sensitive to climate. And it includes mundane things like food poisoning, salmonella food poisoning, also very temperature sensitive, and which we would expect to increase, particularly in poorer and more remote parts of this country. But we're also talking about the effect of increasing frequency and intensity of heatwaves and extreme weather events. We're talking about the effect of climate change on our fresh water supplies in this country, how that's going to continue to do damage to our rural sector, our food production. We know that the disruption of productive life in some parts of rural Australia is exacerbating mental health problems. There's always the tragedy of suicide lurking in the background as farmers lose livelihoods and families get displaced. So it's a pretty wide spectrum of risks to health that we have to be concerned about.

I think it would be fair to say that up until pretty recently our governments in this country and elsewhere have been slow to realise that this is an important part of the story. There's been an undue preoccupation with protecting local economies and not enough recognition that we now face actually a threat to our wellbeing, to our health, and in some parts of the world to our survival. And I must say in this part of the world there is also increasing concern in the background that the effects of climate change, along with population pressures and depletion of fresh water aquifers, exhaustion of agricultural soils, depletion of ocean fisheries, that all of these things will add up to severe food shortages, fresh water shortages, in the region around us, causing destabilisation, most probably, increased flow of environmental refugees. It could lead to lots of tensions and conflicts. And that, of course, inevitably has a range of adverse health consequences. So, you know, it's a big picture and governments really need to get serious about understanding that climate change carries huge risks increasingly over the coming decades to wellbeing and health of human populations.

Interviewer: Now your research here at the National Centre for Epidemiology and Population Health is broader than the area that we've just talked about and there are other research programs that you've had in place for a long time, but linking back to the environment, so you're looking at influences on immune disorders, autoimmune diseases such as multiple sclerosis. Could you talk a little bit more about some of those research programs and what we're learning about the environmental impacts on these particular, I guess, disorders?

Prof. McMichael: Well, I think an interesting general observation is that research into environmental influences on rates of disease in populations has been a bit of a Cinderella area for a number of decades. In my trade, epidemiology, most of the focus of activity, most of the excitement in the last few decades has been, really, on trying to understand how differences in individual behaviours - cigarette smoking, alcohol consumption, use of oral contraceptives, dietary practices, whether you wear seatbelts or not - how those things translate at the individual level into greater or lesser risk of disease occurrence. In the background, of course, we've got these broader influences via things like air pollution or levels of heavy metals or pesticides in our drinking water or our food supplies that exert influences that create risks for whole communities, whole populations. That's not so easy to study, and fewer epidemiologists have applied themselves in that area, unfortunately, because it's my view that in the long run it's those larger-scale influences that impinge on whole communities, whole populations, that are really important in determining the prospects for future health, in determining changes in rates of disease over time.

I must say that it's over the last couple of decades with the emergence of these larger-scale environmental changes, quite unusual in their scale and type, things like climate change and the disruption of ecosystems and the depletion of food producing resources and so on, the emergence of those things has really helped to refocus our minds on the importance of thinking about the environmental influences on human health. So that my work on climate change now is in that sense an extension of my earlier interests in studying the effects of environmental lead exposure in a very large lead smelting community in South Australia, Port Pirie, on the early intellectual development of young children; in studying the effects of radioactive exposures in uranium miners to risks of lung cancer in the miners from Radium Hill in South Australia; and more recently in looking at the ways in which patterns of exposure to sunlight, ultraviolet radiation from the sun, actually influence a number of immune-related disorders. Interestingly one of the things ultraviolet radiation does is actually suppress, to dampen down, immune system activity, so that that can be both detrimental and beneficial. It can be detrimental, of course, in that it could reduce the effectiveness of vaccination programs by having a lazier immune system that doesn't respond so well because it's been damped down by exposure to sunlight.

Interviewer: It seems like a great time to think about a career for younger people in the area of epidemiology. It doesn't matter what their background is - if you're a mathematician, or a computer modeller, or interested in the environment, this would be a great time to get into the game. Any advice to any younger people who are trying to think about what they could do in the future and why should they become an epidemiologist?

Prof. McMichael: Well, I think the first advice is don't be fainthearted. You don't have to imagine that you've got to have a lot of specialist skills. This is an area in which we're all learning. I've had to pick up ideas, information, from a range of disciplines in the last decade - climate scientists, oceanographers, ecologist s. I've been listening to them all and reading their stuff. I didn't have specialised skills in those areas, but I've learnt enough to be able to integrate it now with my epidemiological research and to know with whom I should collaborate. I mean, this is an area in which we need multidisciplinary collaboration. So young people shouldn't imagine that they're entering a terrifying world of science in which they're going to be solely responsible for carrying out research. It'll be a team effort and it'll be good fun and it will be very important.

It's interesting for me to see that there's now quite an upsurge in inquiries that my group is receiving from young people wanting to come on and do PhDs. We weren't getting this five years ago. But I think a number of young people can now see that this is not just a scientifically interesting and challenging area, but this is actually something that has enormous social relevance, enormous consequences for human futures, including the futures of themselves as young people and the families that they might have in future. So there's concern, there's engagement, and there's going to be enormous opportunity. These problems are going to escalate, unfortunately, for the next few decades. We're seriously understaffed. We need a lot more young people coming in to work in the area. So I'd encourage anyone with an inkling of interest in this area to get into it. We need them and they would be doing something very interesting and hugely important.

Interviewer: On that upbeat note I thank you very much for your time and wish you well with your Australian Fellowship. It sounds like you're going to enjoy it. And all the best for the future.

Prof. McMichael: Thank you very much. It's going to be a challenging five years, but it's timely and I think we're going to do some good and important work.

Voice-over:  This podcast was brought to you by the National Health and Medical Research Council, working to build a healthy Australia. You’ll find more information about this and other health and medical research issues on our website, at www.nhmrc.gov.au.