Average land temperatures in Australia are rising and extreme weather conditions are occurring. Some of the health implications of this have been realised and others are yet to play out. HEATWAVES Glenis Lloyd, of NSW Health, believes heatwaves represent the biggest public health burden from climate change for developed countries. "This is where the initial energy and resources should be focused right now" says Lloyd, who envisages a targeted public education campaign for heatwave as pervasive as the "Slip, Slop, Slap" campaign for skin cancer. And there is compelling evidence for decisive action. In 2003 France endured a prolonged heatwave resulting in almost 15,000 extra deaths. During this year's heatwave in Victoria, temperatures were 12 to 15 degrees above normal - exceeding 43 degrees over three consecutive days. Extreme heat can place immense stress on the body. Exposure can cause heat exhaustion, cramps, loss of consciousness and heatstroke. The elderly are particularly vulnerable, due to a reduced thirst response and ability to sweat, and lower cardiovascular fitness necessary for regulating body temperatures. Lloyd says the elderly often compound their risk by choosing not to drink before leaving their homes for fear of needing to find a public toilet.

Lloyd believes that if a person needs treatment for a heat-related illness, the system has already failed. Emphasis should be placed on prevention and education. Solutions include planning events, particularly for the elderly, during cooler months or cooler periods of the day, heatwave plans on buses and public areas (as simple as carrying supplies of water) and ensuring public toilets are in working order, clean and accessible, ideally located along bus routes or other high traffic areas for the elderly. Checking on neighbours during heatwaves should become instinctive - many people died alone in their homes during the heatwaves. Australia has an ageing population and this will become a problem. Longer-term strategies involve urban design - creating cities that do not trap and emanate heat by integrating higher ratios of green space and good public transport. Cutting greenhouse emissions is an obvious and essential strategy. FOOD AND WATER In relation to foodborne diseases, mainly gastroenteritis, a NSW Public Health Bulletin says that for the most common pathogens in food, campylobacter and salmonella, "the notification rate is related to monthly temperature, indicating a potential effect of climate change". Food shortages are also predicted: already evident in areas like the Murray-Darling basin where food production has diminished, and some marine areas where fish stocks are depleted. Food shortages alter food affordability and nutrition can be compromised. Competition for crops and food supply may come from the biofuel industry as it expands and from displaced populations, from within Australia or overseas. The NSW Public Health Bulletin says heavy rain can flush pathogens from catchment areas into drinking water reservoirs and drought can concentrate pollutants in dams and toxic bloom. As the uptake of household rainwater tanks and storage increases, individuals need to be vigilant in preserving and analysing water quality.

MENTAL HEALTH Associate Professor Helen Berry from the Centre for Rural and Remote Mental Health says global warming will affect mental health in three major ways. More severe natural disasters will result in more cases of post traumatic stress disorder. Secondly, compromised health from disease, such as dengue fever in the Australia's far north, can also influence mental health. The final effect - an indirect, but possibly the most pervasive one - relates to how people respond when the economic and social wellbeing of their community is damaged. There is a presumption that farmers and those living in rural areas are more resilient. But drought has been linked to an increased risk of suicide. After 12 years of severe drought in some areas, and projections for further drought, underlying depression in these communities needs to be recognised and resilience strategies adopted. There is evidence of higher levels of hospital admissions related to mental health during extreme heat, particularly for those with existing conditions, and a higher incidence of violence, including domestic violence. During adverse weather conditions, the homeless will be profoundly affected, their plight possibly compounded by their poor physical or mental health.

MOSQUITO-BORNE DISEASE The first generation of modelling climate change scenarios and mosquito-borne disease predicted that dengue virus may eventually be found as far south as Sydney. But Professor Richard Russell, from the University of Sydney Department of Medical Entomology at Westmead Hospital, has urged caution, saying "climate change as currently projected is not likely to provide great cause for public health concern with mosquito-borne disease in Australia". Russell says some projections failed to take into account current and historical distribution of the diseases and vectors (carriers), local ecology, societal changes and the capacity for public health intervention in Australia - absent in many other parts of the world. He says Ross River virus is the most likely mosquito-borne disease to be affected by climate change because it is endemic and annually active in most states and many regions. But mosquito vectors of the virus rely on macropods (kangaroos and wallabies) as hosts, so we first need to understand how climate change will influence macropod populations. The virus may increase in some parts of Australia, yet decrease in others. As for exotic pathogens causing malaria and dengue virus, Russell believes there may be an increase attributable to the number of people entering Australia carrying the viruses.

Water hoarding, tree- and sea-change shifts in population and the creation of wetlands and rehabilitation projects are all human responses to climate change, but they influence mosquito populations. Uncovered rainwater tanks or buckets create new mosquito habitats, and greater populations in coastal areas will naturally increase human exposure to mosquitoes. Prolonged hot weather may also extend the breeding period and life cycle of mosquitoes. AIR QUALITY Air quality is inextricably linked to climate. Fine particulate matter is generated primarily by burning fossil fuels and ozone is formed in warm, polluted air with sunlight. Strong sunlight, combined with increasing heat over summer, generates more ozone from car emissions. The United States Centres for Disease Control and Prevention says ozone causes direct, reversible lung injury; increases premature mortality; worsens respiratory diseases such as asthma, and may cause lasting lung damage. Airborne, fine particulate matter is associated with respiratory and cardiovascular disease and is responsible for increased absences, visits to casualty and hospital admissions. Higher temperatures and carbon dioxide concentrations can increase plant metabolism and pollen production, and possibly fungal growth and mould spores. Pollen and mould spores are allergens and can exacerbate allergies and respiratory conditions.

PEOPLE MOST AT RISK The elderly, infants and young children, and rural communities will be most affected by the human health impact of climate change. Those with chronic medical conditions, particularly respiratory and cardiovascular, are also vulnerable. People working outdoors will need to be aware of how their work practices can affect their health - ideally with the support of industry. Ironically, communities that have contributed little to climate change by way of carbon footprint may suffer the worst effects.

Indigenous populations who have inadequate housing and higher incidences of chronic medical conditions and communicable diseases, combined with limited access to medical services, are more likely to be left vulnerable. Feeding the carbon monster DURING last century, while the Earth's health has degraded, the incidence of major chronic diseases - heart disease, cancer, type II diabetes and chronic lung disease - has risen. They account for 60 per cent of the world's deaths and it seems the same contributing factors are responsible. Environmental health and individual health are inextricably linked. We have changed the way we live. Our bodies, designed for activity, are increasingly sedentary. We drive everywhere, do business and errands online, expect optimal temperature everywhere we go and eat what we like, when we like - regardless of local supply or season.

These behaviours are all carbon-intensive. Automation has polluted the atmosphere and stopped much physical activity. There are buttons to wind windows, open the garage, draw the curtains, change the channel and start the faux fire. Professor Michael Kidd, chairman of Doctors for the Environment Australia, says: "The steps everyone can take to reduce the negative impact on our environment are actually good for our health, too." So, walking or cycling cut pollution while increasing cardiovascular health. And eating less meat - which can significantly reduce your carbon footprint - is part of a healthier diet. NEWS SCAN Compiled by Deborah Smith HEALTH & SCIENCE CONTINUES NEXT PAGE

Walnuts for diabetics Eating walnuts can be of benefit to people with type 2 diabetes. In a University of Wollongong study, 50 overweight adults with non-insulin-treated diabetes followed a well-balanced, low-fat diet. Those given 30 grams of walnuts a day had more good, unsaturated fats in their diets than those who followed a low-fat diet alone. "The walnuts also delivered fibre, vitamin E and other components with antioxidant activity. The walnut group also showed improvements in insulin levels and this may have been due to the presence of good fats in the diet," the university's Professor Linda Tapsell said. Drilling by termite Termites could be a help to Australia's mining industry by bringing up soil samples from far below the Earth's surface for analysis without the need for expensive drilling. This would also help minimise the environmental and cultural effects of mineral exploration, a University of Adelaide geoscience research student, Anna Petts, said. "By simply taking a sample of a termite mound, geologists can gain a good idea as to what minerals and metals can be found in the ground beneath it." In with the old

Products, styles, and practices, like baby names, that gain popularity quickly also are more likely to fall from favour at breakneck speed, a study of 100 years of first names in France and the US has found. But names that slowly increase in popularity persist longer than faddish names. This would counter the theory that the decline of the old is driven by the ascendance of the new, Pennsylvania University researchers said. NYT Pleasant dreams University of Sydney researchers have found the first hard evidence that the special masks doctors prescribe to patients with sleep apnoea actually work. They analysed the sleep patterns of 113 patients by recording brain signals, heartbeat, muscle and eye movement and found the masks helped improve sleeping patterns in 70 per cent of cases. "Interestingly, we found that patients with sleep apnoea have a subtle but different brain activity when asleep," said the University's Dr Jong-Won Kim. They toss and turn and wake more frequently than non-sufferers.