Originally published in ANU Reporter, 23 November 2012
Without immediate action to combat human-induced climate change, we’re not only risking the health of our planet, but also ourselves. SIMON COPLAND reports.
Professor Tony McMichael is issuing a warning: not only will the changing climate affect our planet – killing our coral reefs and melting polar ice – it will also have serious impacts on human health. If we don’t learn from our past, and take action immediately, the future consequences could be devastating.
“The effects of climate changes in the past are really just a small taste of what we could expect to happen in the coming century,” says McMichael, a researcher at the National Centre for Epidemiology and Population health, part of the ANU College of Medicine, Biology and Environment.
It’s safe to say that McMichael knows what he’s talking about. The world-leading epidemiologist was looking at the effects of climate change long before it was a hot topic.
“I have been interested in environmental epidemiology for around 40 years,” he says.
“I became especially interested in climate and health around 1990, when I noticed the increasing international concern about depletion of stratospheric ozone and the increased risks of skin cancer and eye disorders. I sensed that the rather more complex issue of human-induced climate change would pose even greater health risks.
“Participating in scientific and public discussion about climate change in those early years, however, made it very clear to me that we weren’t seeing the full picture. We worried about climatic impacts on river flows, polar bears and economic growth – but not the biological consequences for humans themselves.”
McMichael is seeking a better understanding of the history of Earth’s climate and its impact on human health in his new book, which has the working title When climates change – famines, fevers and fates of populations.
“Early on, the main issue for human health and survival was finding ways to produce food,” he says. “People were continuing to spread out into new territory, so there was a lot to learn about what would grow and what wouldn’t. A lot of early health problems, such as undernutrition and starvation, arose from food crises that had much to do with fluctuations in climate.”
McMichael says the health impacts of human-induced climate change are wide-ranging.
“In public discussion, most people say, ‘ah yes, climate change and health, that will mean more heatwaves and floods and mosquitoes moving south’. Those are important issues, but they are just the tip of the iceberg.”
The rest of the iceberg is more difficult to study and foresee.
“For one thing, we are still in a relatively early stage of what is probably a long process of climate change,” says McMichael. “So it’s not easy to make the call and say, ‘that particular climatic event or that rise in the dengue fever cases in Queensland is due to warming’.
“The relationship between changes in population health and climate change is not as clear-cut as seeing the Arctic ice melt. For that, there’s only one explanation: the environment is getting warmer.
The causes of human health and disease are much more complex.
“We need to look for consistent patterns.
“For example, we have studied various rural communities that have experienced the stresses of this last decade of drought. Episodes like that enable us to identify the typical adverse health consequences, including effects on community morale, mental health problems and impacts of extreme heat for outdoor workers.”
After 12 years at ANU, McMichael is moving from a full-time position to continue his work in ‘semi-retirement’ mode. In early November, this occasion was marked with a Festschrift – a celebration including a two-day conference. A commemorative book will be be published next year. The book will be a collation of invited chapters covering the topics McMichael has focused on throughout his career, with subjects including the politics of smoking and cancer and the health impacts of environmental lead contamination.
“It was a great honour to have my Centre, with support from the College and the University, put on the Festschrift,” says McMichael. “It took me by surprise when it was suggested, but it was a nice opportunity to draw together a number of threads from the work that my research group and I have done.”
Two such threads are his understanding of climate history and his passion for taking positive action to adapt to current fluctuations.
“It’s one thing to clarify the current and future risks to health, but it is also important to discuss the actions our society must take to avert those risks,” says McMichael.
“Human-induced climate change is already happening and we must take protective action. By far the most important, of course, is to curtail the problem at source by curbing greenhouse emissions.
“Other adaptations are relatively straightforward, such as near-term responses to the prospect of more severe heatwaves. Our studies of patterns of deaths in Australia during extremes of heat indicate that the ongoing temperature rise, with increasingly hot periods and heatwaves, is causing additional deaths.
“We’ve built our cities in ways that often maximise them as heat traps. That’s a problem, especially for inner urban populations: during a heatwave, not only do residents get exposed to the extremes during the day, but temperatures don’t go down at night. So we should have more green space, more ventilation, and better insulation of private houses and public buildings.
“We also need more effective early-warning systems for heatwaves, supported by media dissemination and greater local community attention to those who are old or frail and living on their own.”
Climate change also has implications for the spread of infectious diseases.
“We need improved surveillance methods for disease,” says McMichael. “For example, with warming, mosquito-borne Japanese Encephalitis could spread to Australia via Cape York. Increasingly, ‘sentinel’ birds are used as indicators: if the disease enters Australia, infection of these birds provides an early warning.”
Ultimately, McMichael hopes that his life’s work will help shape our future.
“There are warning signals from history for us to learn from. But we need transformations, not just tinkering,” he says.