The Australian government is allocating more than $6 million to investigate the potential impact of climate change on health, as the country's southeasern corner endures its most severe heatwave since 1908. Meanwhile, a new U.S. study says the damaging effects of a climate change have become largely irreversible. 

As parts of southern Australia sizzle in the sort of conditions not seen for a hundred years, the federal government has announced a multi-million dollar study on the impact of climate change on health.

Warmer weather could have unhealthy consequences

Researchers believe that a warmer climate is likely to have a profound impact on the well-being of Australians, including a higher incidence of mosquito-borne illnesses, heat exposure and mental illness.

Health authorities in northern Queensland are currently trying to contain an outbreak of potentially fatal dengue fever, which has so far affected about 200 people.

Professor Tony McMichael from the Australian National University says warmer weather attributed to climate change could prove to be catastrophic to health.

"There are simple direct effects like the impact of increased frequency and severity of heat waves on rates of death; particularly in older persons," the professor said. "Of course with increased climatic variability, more extreme events, we're going to see also more injury and death and post-traumatic stress from things like cyclones and extreme bushfires."

Very young and old are most susceptible

The very young and the old are considered most susceptible to exposure to extreme heat, which can cause heart attacks.

Researchers also worry that worsening drought conditions across Australia's arid interior could trigger more mental illness in the hard-pressed farming community.

This week, a U.S. study has shown that the damage caused by a warming atmosphere cannot be reversed even if carbon dioxide emissions, which are widely blamed for climate change, are completely stopped.

The report by the National Oceanic and Atmospheric Administration shows that changes in surface temperature, rainfall and sea level will persist for more than a thousand years.

As south-eastern parts of Australia sweated in temperatures in excess of 45 Celsius, railway lines in Melbourne buckled under the heat and demand for air-conditioning has put the electricity system under unprecedented strain.  The very hot weather is expected to continue for several more days.