Vulnerability in a greying Australia: the aged in a changing climate

Population ageing will be one of the most critical demographic and social issues in Australia over the next few decades. People aged over 65 currently make up 16% of our population and as cohorts of baby-boomers turn 65 (those born in the years between 1946 and 1960,) this will increase to over 21% within the next decade. By 2040 25% of all Australians will be aged over 65 including more than 1.4 million Australians aged over 85.

Over the last two decades people aged over 85 have increased by more than 125% compared with an overall population increase of 34%.

We are surely facing a different Australia. In the context of a changing climate the implications of a rapidly ageing Australia have yet to be fully appreciated.

When projections of ageing are matched with social and epidemiological data about increasing chronic disease, disability, handicap, drug dependence and poverty it is clear that the vulnerability of Australia’s aged population to climate change will be a critical issue over the next 25-50 years.

So what is the likely climate change scenario for Australia and what are the dimensions of vulnerability for Australia’s old population? Australia currently generates less than 2% of global emissions but on a per capita basis is up there among the worlds’ highest countries largely because of its export of primary resources including mining, agriculture and metal products, while its energy sector remains dependent upon coal-fired electricity. As well, Australia ranks among the worlds most urbanised countries with 75% of its population living in large cities.

Australia’s geographical location and size add a further dimension ensuring that the country experiences a widely variable climate. Changes in temperature with a warming in most areas and longer drier spells with some very hot days are more than likely, with Southern Australia in particular facing lower rainfall and higher temperatures, an outcome which may impact upon agriculture and food production as well as upon the aged population.

Most Australians including the old, will face a wide range of climatic events over the next 25-50 years including extreme weather events, changes in the distribution of vector-borne diseases, reduced fresh water supplies, compromised agriculture (poor soil and food quality), and degraded air quality, periods of heat waves and drought as well as increasing pressure on urban living conditions particularly for those living in large cities.

All these elements of climate change have the potential to affect our environment in many ways placing stress on all our population but disproportionally on the most vulnerable, notably the very young, the old, the poor and those suffering from chronic illness. Old people are particularly at risk due to problems of mobility, changes in physiology, medication dependence and often limited access to resources. Older people also face the risk of increased susceptibility to disease, to stress associated with changes in water and food supply as well as issues relating to reduced mobility.

Generally climate change will impact on Australia’s elderly population in a number of important ways. There is plenty of evidence of the aged sensitivity to temperature extremes (heat and cold waves). Heat waves in particular will play an important role in the health of old people largely due to the impact on the body’s thermoregulatory mechanism, the water and electrolyte balance and on the increased demands made on the cardiovascular system.

Generally the healthy aged can adapt to exposure to high temperatures but for people with impaired cardiovascular systems such temperatures can have a fatal impact. Áustralia has a long history of heat waves many claiming more than 350 deaths. The 1938 heat wave in Victoria claimed at least 437 deaths and during a more recent heat wave in south-eastern Australia in 2009 where temperatures exceeded 45 degrees and hundreds were treated for heat related illness at least 374  people died.

Can we expect our aged population to adapt easily to such extremes? At the moment I doubt it. The old with impaired respiratory systems such as asthmatics are also sensitive to a wide range of irritants and allergens such as dust mites, pollens, moulds and fungi as well as concentrations of ozone, sulphur and nitrogen oxide in the atmosphere. It seems more than likely that climate change will produce a surge in the production of such elements impacting upon air quality particularly in our large cities. Such changes will impact upon elderly people suffering from chronic illness, particularly people with heart and lung disease as well as those with diabetes.

Levels of chronic disease, disability and handicap as well as overweight and obesity are currently high in Australia. At least 50% of all Australians suffer from at least one chronic condition and 60% of all the aged suffer from two or more chronic conditions. Australia also suffers from some of the highest overweight and obesity rates in the world. Two thirds of all Australians aged over 18 are overweight or obese including 78% of those aged between 65 and 74. Australia also possesses one of the highest asthma rates in the world and possibly one in every nine Australians suffer from the disease. Cardio-vascular disease is also important affecting one in every six Australians including 66% of all Australians aged over 75.

All this undoubtedly increases the vulnerability of our aged population to climate change. It is also likely that changes in rainfall, temperature and humidity may affect the distribution of vector-borne diseases like dengue. Until the 1940s dengue extended over a wide area of Eastern Australia. After 1943 dengue and its mosquito vector retreated to parts of Northern Queensland largely because of changes in technology and human behaviour e.g. the extension of reticulated water supplies and the decline of domestic water tanks, the emergence of refrigeration and the disappearance of ant pots and the replacement of steam trains by diesel and the related disappearance of fire buckets and water tanks at stations. All this changed the breeding spots of the mosquito vector which spread dengue. It is now quite possible that lengthy periods of drought and water shortages could see the reappearance of rainwater storage tanks throughout parts of Eastern Australia providing potential breeding grounds for mosquitos.

While turning 65 does not necessarily make people more vulnerable to climate change the impact is related to the physiological and psychological health as well as social and economic conditions enjoyed by the aged. There is little doubt that older people who are poorer, less educated, less mobile and possess fewer social connections are also at considerable risk. The oldest old, those aged over 85 are most likely to be affected by climate change largely because of physical frailty, pre-existing chronic health conditions, high medication dependence and lack of mobility.

Up until now climate and climate change have rarely been considered by those advocating social and health support programs to cope with an ageing population. It is clear that there is a need to develop services and support structures that are sensitive to the needs of the elderly in the context of a changing climate. It seems clear that we need to appreciate the impact that climate change will have on the health and wellbeing of older Australians. Importantly we need an integrated approach to health and social planning which recognises the vulnerability of our elderly population in a warmer changing world. We also need to develop strategies to face heat waves, changes in air quality and the changing distribution of vector-borne disease.