This blog is part of a series on sustainable healthcare, which looks at health, sustainability, and the interplay between the two. The blog is coordinated by the Centre for Sustainable Healthcare and shares ideas from experts across the healthcare field.

The World Health Organization and the Lancet Commission have both stated that climate change is the largest threat to human health in the 21st Century. Does this threat extend to mental health? Weather systems are likely to become more unstable as global temperatures rise, but could unstable weather have an effect on the development of mental disorders?

The floods earlier this year were an awakening to the devastation that severe weather can inflict on our lives, even here in the UK. It was clear to all that the people affected were under a huge amount of stress. There is growing concern that the stress caused directly by severe weather, and the prolonged disruption to people’s lives, may have a significant effect on both mental health incidence and prevalence.

So, what is the current evidence for the effects of climate change on mental health? After the 2007 floods in the UK, the Health Protection Agency stated that flooding has significant mental health effects, while a paper in the Psychiatric Bulletin stated that flooding exacerbates anxiety and depression in older people. And, during the 1995 heat wave in England suicide increased by 46.9%. This study also found that every 1 degrees C increase in mean temperature above 18 degrees C was associated with a 3.8% and 5.0% rise in suicide and violent suicide, respectively.

In the wider world, droughts have been shown to be associated with increased stress levels, and cyclones have been shown to cause persisting post-traumatic stress disorder in young people.

So, the evidence shows that even subtle changes to weather systems can have a dramatic effect on mental health. Climate change will have a large impact on mental health services and the way we work. In light of this, why are no psychiatrists talking about it? Mental health services need to adapt to these changes, but—most importantly—psychiatrists need to respond by reducing their clinical carbon footprint. They could lead the way in promoting a service that is good for the environment and good for patients.

There are many opportunities to improve the sustainability of mental healthcare, but ensuring medication adherence is a low hanging fruit. In 2010, an estimated 22% of NHS England’s greenhouse gas emissions were attributable to pharmaceuticals, and evidence suggests that as much as 50% of psychotropic medications are actually not taken. Therefore, by ensuring that medications are only given to those who will take them, the carbon footprint could be substantially reduced.

The mental health sustainability summit on 1 October this year at the Royal College of Psychiatrists aims to address these issues, and will discuss the challenge we face in climate change and its effects on mental health.

Daniel Maughan is the Royal College of Psychiatrists sustainability fellow and is currently working with the Centre for Sustainable Healthcare, the Royal College of Psychiatrists, and the University of Warwick to stimulate the adoption of sustainable practices in mental health trusts around the country.

Competing interests: I declare that I have read and understood the BMJ policy on declaration of interests and I have no relevant interests to declare.