Health Impacts in Australia

• By 2030, annual average temperatures are predicted to be 0.4 to 2.0°C higher over most of Australia, with slightly less warming in some coastal areas and Tasmania, and the potential for greater warming in the north-west.

• Within 800 kilometres of the Australian coast, temperatures will warm from 0.1 degree to 1.3 degrees by 2020. By 2050, it could warm anywhere from 0.3 to 3.4 degrees and, by 2080, the mean temperature could be 6.7 degrees warmer than it is now.

• Social and mental health problems will increase in all communities due to food shortages, social conflict for resources and expanding communities from environmental refugees.

• By 2100, annual average temperatures are predicted to increase by 1.0 to 6.0°C over most of Australia depending on emission scenario and climate model. The range of warming is greatest in spring and least in winter. In the north-west, the greatest potential warming occurs in summer.

• Rainfall is projected to remain at similar levels in the tropical north, with some increases in the northwest and centre, and continuing decreases in the southwest and east (CSIRO 2001).

• Where average rainfall increases there would be more extremely wet years, and where average rainfall decreases there would be more droughts. Rainfall extremes may also be amplified by increased short-term variability (IPCC 2001; Milly et al. 2002).

• Social and mental health problems will increase in rural communities affected by falling farm yields

• Diverse health consequences of increased immigration/refugee flows in Asia-Pacific region with the accompanying risks of mental and physical health problems, and conflict.

• The re-introduction of malaria into northern Australia would certainly constitute serious and compelling evidence of a significant health hazard from climate change," Professor Tony McMichael Canberra's National Centre for Epidemiology and Population Health, prepared the report for the Intergovernmental Panel on Climate Change.

• Increase spread of infectious diseases carried by climate-sensitive insects or other organisms

• injury and death from extreme weather events (storms, cyclones, floods, fires)

• civil strife and conflict over dwindling climate-related resources (fresh water and arable land), especially in already resource-poor regions

• The reliance by large numbers of people on single water supplies poses another potential threat. The Cryptosporidium microbe contaminates water after heavy rainfall, causing diarrhoea and severe illness. It is one of the organisms thought likely to become more prevalent if greenhouse weather patterns persist.

• Blue-green algae blooms in rivers and dams are expected to be more frequent. The liver and nerve toxins produced by such blooms could cause greater health problems over larger areas.

• Even the purity of the air we breathe would change. Air pollution – an important cause of death and illness in Australian cities through respiratory diseases and reduced lung function – is tipped to worsen. Ozone is already a problem pollutant that will increase with a hotter, drier climate. A rise in airborne allergens could also worsen asthma and hay fever. http://www.abc.net.au/health/regions/features/climatechange/

• heatwaves and fires are virtually certain to increase in intensity and frequency.

• Floods, landslides, droughts and storm surges are very likely to become more frequent and intense.

• Climate change will decrease the area of arable lands currently used for agricultural production in Queensland.

• increase in drought frequency is a predicted decrease in the average moisture of Queensland soils.

• Evaporation will also have a negative impact on water storage, with greater losses from dams and increased risk of algal blooms. There is moderate confidence that climate change will also lead to a reduction in river and stream flow in Queensland. (Walsh et al. 2001)

• the higher the temperature, the more children present at hospitals with fevers and gastroenteritis

A13_s3

HEAT-RELATED MORTALITY

Evidence for a climate relationship

Climate change will bring an increase in the frequency and, probably, the intensity of heatwaves

(Meehl and Tebaldi 2004; Schar et al. 2004), along with warmer summers and milder winters (IPCC 2001).

the relatively steep mortality increase at hot temperatures.

An increase in mortality with colder temperatures (McMichael et al. In Press) will be experienced.

There is strong evidence that these summer deaths are indeed the result of heat-related conditions alone (UK NHS 2005).

In cool temperate countries, cardiovascular disease shows the strongest temperature mortality relationship, followed by respiratory disease and then “all-cause” mortality. These relationships are supported by physiological evidence for direct links between high and low temperatures and increased blood pressure, viscosity and heart rate for cardiovascular disease (Keatinge et al 1984, Pan et al 1995) and broncho-constriction for pulmonary disease (Schanning et al 1986).

TEMPERATURE - ATTRIBUTABLE DEATHS AT 2100

By 2100, the number of deaths due to high temperature for all cities combined is expected to increase by a half to three times the baseline number – depending on which greenhouse gas emissions trajectory is followed. From the baseline of around 1100, annual deaths could increase to between 1700 and 1900 if the 450ppm scenario was adopted. Under the higher emission scenario, deaths could increase to between 2600 and 3200.

the annual temperature-attributable mortality rate in Perth is estimated to be 495/100 000 by 2100 (more than double present values).

IMPLICATIONS FOR AN AGEING POPULATION

By 2100 the population is predicted to change in total size by -4% (to 18.8 million), +34% (26.4 million), or +92% (37.7 million), depending on Australian Bureau of Statistics population scenarios (Trewin 2003).

the proportion of people aged over 65 years is expected to be very similar under the three projection scenarios – increasing from 13% in 2002 to 29-32% around 2100.

The proportion of people in this age group, relative to 2002, will therefore increase 2.5 to 4.7 times.

On this basis, the number of heat-related deaths in people aged 65 years and older is more likely to be in the order of 4 000 to 15 000 each year

Projected change in Australian population size and structure around 2100, and effect on the annual number of temperature-related deaths in people over 65 years in capital cities (Australian Bureau of Statistics).

A13_s4