However even with our decades of medical training, one of the biggest opportunities to save millions of lives today doesn't require a single prescription, vaccine, or scalpel.

Getting to net zero emissions and phasing out fossil fuels, could save over 8 million lives globally every year.

Fossil fuels are deadly. Recent research from Harvard University found that air pollution from burning fossil fuels was responsible for more than 8 million deaths globally in 2018. That's nearly one in five deaths.

Further, the consequence of burning fossil fuels - climate change - has its own health toll. In Australia, there were more than 400 deaths and over 4,000 hospitalisations from the Black Summer bushfire smoke. And from 2006 to 2017, more than 36,000 Australians suffered premature deaths directly or indirectly from extreme heat.

Disappointingly, Australia has no plan to deal with climate-health impacts. Our federal government has not set an adequate emissions reduction target for 2030 nor a net zero date, and is unprepared for the health impacts of accelerating climate change.

However, this hasn't stopped doctors' efforts to protect Australians from the deadly impacts of burning fossil fuels and climate change.

Last week, the Australian Medical Association and Doctors for the Environment Australia called for the Australian health system to achieve net zero by 2040 and reduce emissions by 80 percent by 2030. They also called for the formation of a national Sustainable Healthcare Unit to guide and coordinate the transition.

This target is crucial because although the health sector's role is to manage disease, disturbingly, it's also a major contributor to it. If the global health sector were a country, it would be the fifth largest greenhouse-gas emitter on the planet.

The carbon footprint of the Australian health system is 7 per cent of our national emissions - more than the total emissions of South Australia. We use fossil fuel-based energy, transport and manufactured goods, and produce vast quantities of waste.

Ironically, as it currently operates, the healthcare sector is producing its own patients.

We have a responsibility then, to decarbonise, whilst continuing to provide quality healthcare.

Around the world, health systems are waking up to this challenge and acting fast. The world's largest healthcare system, the UK's National Health Service (NHS), is aiming for net zero by 2040. It has already reduced its carbon footprint by nearly 20 per cent in the past decade - saving almost GBP 2 billion. In the US, healthcare group Kaiser Permanente is close to becoming carbon-neutral.

The Australian health system needs a range of concurrent initiatives across the whole system to achieve net zero.

Firstly, just as we forbade smoking and prohibited asbestos in buildings, we must phase out fossil fuel energy from our facilities. We need to electrify everything, shift to renewable energy, improve efficiencies, install smart monitoring and better design hospitals.

States and territories are already leading the way. Canberra Hospital is on track to be the first 100 per cent renewable energy-powered hospital in the country, using electric heat pumps and no gas. Queensland's health minister recently pledged to expand the solar and energy efficiency hospital scheme to 50 sites across the state. However, modernising energy and buildings is only part of the solution.

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Health professionals also have an important role to play in preventing illness and reducing low-value care (care where the harms and risks of medical tests and procedures outweigh any benefits), prudent prescribing, expanding low-carbon models of care such as telehealth, and shifting to lower carbon but clinically equivalent anaesthetic gases, respiratory inhalers and medicines.

This work is under way in many parts of the health system but needs to be coordinated and accelerated.

The good news is that these efforts are all possible, and will have so many knock-on benefits: health system cost savings, cleaner air, healthier diets, cooler cities, more jobs and stronger, more resilient economies.

As health professionals, we just need to get on with it. After all, saving lives is our job.