Australia’s healthcare system is responsible for just over 7 per cent of the nation’s carbon footprint.

An analysis from the University of Sydney has found hospitals and pharmaceutical companies form the bulk of health-related emissions.

Lobby group Doctors for the Environment Australia (DEA) says the federal government should help states and territories make hospitals more energy-efficient.

The researchers took 2014-15 financial data from the Australian Institute of Health and Welfare used mathematical modelling to determine a carbon dioxide equivalent emissions factor for each of 15 different sectors, including public and private hospitals, dental services and private practice.

“We found that the carbon footprint attributed to healthcare was 7 per cent of Australia’s total; that is, similar to the entire carbon emissions associated with the activities of 7 per cent of Australians,” the study found.

The study estimated that the health sector was responsible for 35,772 kilotonnes of Australia’s 494,930 kilotonnes of carbon emissions in 2014-15.

Hospitals and the pharmaceutical industry were together found to be responsible for two-thirds of the total healthcare carbon footprint.

Using the same technique overseas, other analyses have found healthcare contributed about 3 per cent of total emissions in England and 10 per cent in the US.

In Australia, anaesthetic gases - desflurane and nitrous oxide in particular - were found to be a significant contributor to hospital carbon emissions.

“The anaesthetic gases we pump into the atmosphere have a very high global warming potential, up there with chlorofluorocarbons,” said Dr Forbes McGain, a co-author on the study and an anaesthetist and intensive care physician with Western Health in Melbourne.

He said alternatives such as intravenous anaesthetics would help reduce healthcare’s carbon footprint.

“Though there are some reasons why gases might be used, such as fast onset and offset, Denmark for example uses intravenous anaesthesia much more commonly than gases,” Dr McGain said.

“So cultural factors are extremely important, as well as marketing by pharmaceutical companies to influence doctors. Gases won’t be completely replaced, but they don’t need to be used as commonly as they are.”

Other ways to curb carbon emissions could include installing more renewable energy facilities at hospitals and reducing the number of patients attending hospitals.

“Health promotion efforts to encourage healthy lifestyles will help to reduce the need for access to healthcare and on the reliance for pharmaceuticals, the sectors with the highest direct carbon dioxide equivalent emissions emissions,” the authors wrote.

“Messages on how to maintain a healthy lifestyle might help to reduce individual and community vulnerability to the health effects of climate change and, ironically, help lower the main contributing factor – carbon emissions.”

Dr McGain says the federal government must get involved.

“But to achieve emissions reductions in healthcare will be a massive effort, requiring support and funding at the federal level,” he said.

“Climate change is a health problem, and the health sector should be leading the way in addressing it.”