The issue of health must urgently be brought further up the environmental agenda, said college president Jackie Taylor, as COP26 became the first climate conference to include a health pavilion.
"As a college we have a responsibility to speak up and say that climate change is a global health emergency,” she said.
Dr Taylor added: “I think that probably hasn't been appreciated enough.
“The focus has been on the environment, deforestation, the polar ice caps, polar bears, habitats for rare creatures … that’s obviously important, but we have to factor into that that we are creatures of this planet and our health is already being impacted upon.”
Developing countries are by far the most affected by climate change, Dr Taylor said, but Scotland and the UK are already feeling the impact on health.
Air pollution, which contributes to asthma and COPD attacks, was named as a cause of death for a nine-year-old girl in London last year.
Wildfires also impact on air quality and are a risk to life, along with flooding.
The Scottish Government issued guidance to emergency services in Scotland in September, telling them to prepare for more of both as a result of climate change.
And while heatwaves are less severe in Scotland, thousands of additional deaths linked to extreme heat have been recorded elsewhere in the UK.
Changing weather patterns influence the movement of disease-carriers such as mosquitoes and ticks, potentially increasing the risk of vector-borne diseases such as malaria and yellow fever, Dr Taylor said.
This was echoed by Parveen Kumar, ambassador of the UK Health Alliance on Climate Change (UKHACC) in an address to the RCPSG this week, in which she labelled it “astounding” that malaria may be re-introduced to the UK because of climate change.
Dr Kumar also highlighted the impact of climate change on mental health and stress.
“I think there has been a growing appreciation of the importance of placing health very centrally within the climate change agenda,” said Dr Taylor.
“We've been thinking a lot about planetary health and then we need to think about population health.
“Climate change is the biggest public health crisis facing us.”
Dr Taylor called for “action, not words” and recognised the impact of health services on climate change.
“There are two ways of looking at it,” she said.
"Climate change impacts on health in so many ways, but healthcare itself contributes to CO2 emissions and therefore climate change. So we do need to try and set our own house in order in healthcare.”
The RCPSG will focus on sustainable healthcare and sustainable food, Dr Taylor said, and is carrying out a review of its own practices to reduce impact on the planet.
It comes as the Scottish Government committed to NHS Scotland achieving net zero by 2045, with the aim to bring this forward to 2040 after consultation on a draft climate emergency and sustainability strategy published this week.
The commitment includes net zero route maps for all health boards by the end of 2022.
All buildings owned by NHS Scotland will aim to use renewable heat by 2038, and all small and medium health service vehicles will be net zero by 2025.
"The climate emergency is not just an environmental crisis – it is also a public health crisis,” said health secretary Humza Yousaf, announcing the target.
"I am determined to help the NHS cut emissions and create an environmentally and socially sustainable health service. Working together, we can realise the benefits for people’s health that a healthy natural and social environment can provide.”
Richard Smith, chair of the UK Health Alliance on Climate Change, said health services around the world must urgently work to cut emissions.
“When you start from the premise, as everybody agrees, that climate change is the major threat to health in the world, dwarfing all others including the pandemic, it’s kind of crazy that health care systems have carbon footprints that are going up,” he said.
“If you put the carbon footprint together of all the health systems in the world, that it would be the fifth biggest emitter of carbon.”
Dr Smith said he believed that in future health services will consider treatments and systems based more on their carbon emissions than their cost.
Some high-emitting gases, such as the anaesthetic desflurane, would not have been allowed on the market if it were introduced today, he said.
Many anaesthetists now avoid desflurane and chose other options with no detriment to the patient, he added.
Nitrous oxide, or laughing gas, is also increasingly being avoided, as well as certain inhalers with poor environmental credentials.
Hospitals are looking at ways to reduce emissions, especially in surgery where more gases, PPE and equipment tend to be used.
There is a growing reckoning on the use of PPE, Dr Smith said, as in many cases this is over-used, for example when hand-washing could replace single-use gloves for some tasks.
The pandemic has set this back, he added.
Dr Smith said he believed these changes should not diminish patient care or compromise any standards of hygiene and infection control.
“Almost all the changes we need to make will actually be beneficial for health,” he said, adding: “The other argument is the sheer urgency of this.
“I think people don't really grasp just how urgent it is, and how substantial the risks are.”
Clinical practice “cannot go on in the same way”, he said.