AUSTRALIA will have to contend with the health consequences of intensifying climatic extremes as heatwaves, floods, droughts and fires become more frequent, say experts who are calling for urgent action to reduce carbon dioxide (CO2) emissions.
In a Narrative Review in this week’s MJA, Professor Elizabeth Hanna, Honorary Senior Fellow at the Climate Change Institute, Australian National University, and Dr Lachlan McIver, of Médecins sans Frontières, Geneva, said that urgent action was needed to reduce emissions and to realign health services to address shifts in disease burden.
“Current trends suggest a future of increasing heatwaves, even greater rainfall variability, and more fires,” the researchers wrote, noting that current emission rates were likely to lead to a warming of 4°C by 2100.
“Additional heat is likely to generate fewer winter respiratory deaths yet more heat exposure morbidity and mortality. Further exacerbations of Australia’s extreme rainfall variability will intensify water shortages and storm and flood damage, compounded by likely societal interruptions and health challenges.”
Speaking in an MJA InSight podcast, Professor Hanna said that Australia’s status as a wealthy, resource-rich nation provided some protection from the extreme consequences of climate change, but we still faced significant challenges.
“As far as [high income] nations are concerned, we’re an outlier in being highly vulnerable,” Professor Hanna said. “We have the world’s highest natural variability in rainfall, and so further exacerbation of that is going to really stress out our water supplies and our agriculture. We’re also far hotter than most of the other [high income] countries.”
Associate Professor Grant Blashki, a GP and Associate Professor at the Nossal Institute for Global Health, and the Melbourne Sustainable Society Institute at the University of Melbourne, said that the MJA article was a reminder to Australian politicians of the high stakes for future generations’ health.
“Climate change poses a global threat to ongoing gains in public health, and for Australia, as a very dry continent, we are vulnerable to worsening heat waves and other extreme weather events,” said Professor Blashki, who is co-author on an article published on 5 April 2018 discussing the importance of embedding health in the climate change agenda.
“While policy makers debate and negotiate about how quickly to reduce greenhouse gas emissions, the fundamental scientific physical processes that drive climate change continue to raise the average global temperature and put the long term health of Australians at risk.”
Professor Shilu Tong, Adjunct Professor at the Faculty of Health, Queensland University of Technology, said that although climate change had been increasingly recognised as the biggest threat to global health in the 21st century, we were not well prepared for shifts in disease burden, for example, changing mortality patterns and increased likelihood of heat stress.
Professor Tong pointed to recent research he had conducted in this area, including a 2016 finding that increased summer temperature-related deaths were likely in Brisbane, Sydney and Melbourne in the coming decades.
“More action is urgently required to mitigate greenhouse gases emissions and develop public health adaptation plans to tackle the increasing health risks of climate change,” Professor Tong told MJA InSight.
The MJA authors wrote that many vector-borne diseases were climate sensitive, as mosquito densities related to rainfall and temperature, and it was possible that cases could spread to southern regions of Australia. They noted, however, that the picture for climate-sensitive vector-borne diseases remained unclear.
Professor Steven Chown, Professor of Biological Sciences at Monash University, said that the authors were right to be circumspect about the impact of climate change on the spread of vector-borne disease.
“There’s an interaction between what’s being done in the medical research area in reducing the burden of vector-borne diseases – for example, by the World Mosquito Program – and what climate change is doing to improve the situation for indigenous vectors,” Professor Chown told MJA InSight. “So, I think [the MJA authors] are right to be circumspect in the way that that’s actually going to play out.”
He said that attention to biosecurity measures was essential in keeping these risks in check.
“There’s a little mosquito species called Aedes albopictus. It’s a very effective vector of these arthropod-borne viruses [such as] dengue and Zika,” he said.
While A. albopictus was not currently in Australia, it had been detected and eliminated in both the Torres Strait Islands and in Melbourne, Professor Chown said.
“If our biosecurity systems fail and this species gets in, we could have substantial difficulty, so we have to pay very careful attention to the interaction between how the local environment is changing and how we manage the biosecurity risks to Australia.”
Professor Chown also highlighted the added climate change threat posed in Australia’s urban environment.
“Cities have huge benefits, but they also have an additional burden since they tend to be much warmer than their surrounding environments, varying from about 1° in the tropics to about 3° in temperate areas,” he said.
“Quite a few Australian cities are undertaking plans to mitigate this through tree planting, green building design and so on, but it is something to bear in mind from a human health perspective because most of the Australian population lives in cities.”
Despite the grim picture presented in the MJA article, Professors Tong and Chown said that there was some hope on the horizon.
“The central aim of the Paris Agreement is to keep any global temperature rise this century well below 2°C above pre-industrial levels,” Professor Tong said. “The good news is that 175 of 197 parties have ratified the convention. International efforts to reduce greenhouse gases emissions will undoubtedly facilitate mitigating the more severe effects of climate change on health.”
Professor Chown shared this view but noted that Australia had lagged in its commitment to tackling increasing CO2 emissions.
“Australia has been slow in taking [action on climate change] but I think there is opportunity still to do so. It’s essentially a compound interest problem – we are going to keep compounding our difficulties into the future, if we don’t address them now,” he said.
“And every now and then, we have these amazing rays of hope here, as we saw in South Australia with significant developments in renewables and storage.”
Still, resistance to the science behind anthropogenic climate change has remained in some quarters, including the medical profession.
Professor Blashki said that the climate change issue had become a political football around the world, with varied and sometimes non-scientific perspectives. However, he said, doctors had a “long and proud history” of taking action on public health issues that affected their patients.
“For doctors who are worried about this problem, they can get involved with groups such as Doctors for the Environment, lobby their local members or explore ways to move towards making their practice a GreenClinic,” Professor Blashki said.
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