Predicted impacts of climate change on health range from heat stroke to famine. A framework published in December now sheds light on the largely overlooked area of mental health by tracing at least three “causal pathways”.
Before getting into more details on this, I should mention the recent disputes of evidence behind climate change predictions. In a nutshell: just weeks after the controversy over emails hacked from a server at the University of East Anglia Climatic Research Unit, the Intergovernmental Panel of Climate Change (IPCC) admitted a mistake in forecasting that Himalayan glaciers would melt by 2035. This was followed by further claims that the IPCC was wrong to link climate change with a higher number and severity of natural disasters – claims that were refuted by the Panel. Responding to all this John Beddington, the UK government’s Chief Scientific Adviser has called for more focus on uncertainty when presenting predictions on climate change.
I suspect it may become more difficult to speak of causal links in climate-change science from here on. Thinking back to the illegal drugs controversy of last November in the UK, which to me raised questions around handling uncertainty, it’s becoming clearer that we need to work out how to capture and communicate what we don’t know without stifling action.
But let’s get back to climate and mental health.
According to the World Health Organization, threats to health posed by changes to the global climate are real and already underway, affecting millions of people. At current temperature change predictions, millions more over the next two decades will need to cope with rising heat stress and air pollution, more frequent extreme weather events, food and water scarcity, and changes in the occurrence or spread of diseases transmitted via water, food, or animal vectors.
In a paper published in the International Journal of Public Health, Helen Louise Berry and colleagues argue that the tally disregards mental health problems linked to climate change directly and indirectly.
Anticipating impacts on physical health, scientists have stressed the need to draw response plans that pay special attention to population groups whose defences against disease are weak [PDF] for reasons that could be biological, economic or geographical. These include children, the poor, residents of low-lying coastal areas, and people with chronic health conditions and cognitive problems. Indigenous people make up another group with special vulnerability to the health effects of climate change, partly due to a history of social disadvantage and cultural concepts of well-being.
Mental health is on course to become the second greatest cause of non-fatal illness globally by 2030. But until recently this aspect of ill-health has been all but ignored in discussions of how to respond to climate-related health impacts, according to the authors. With a literature review they sketch out how climatic conditions could affect mental health – the first and most obvious example being the trauma known to affect displaced people in the aftermath of a natural disaster. But less well-understood mental disorders may also linger long after an event, or surface gradually during less acute weather conditions such as drought.
Berry et al. then point to psychological problems as a secondary outcome of both physical illness and a degraded natural or social environment. They explain that as weather conditions become more extreme, some people may be forced to work less and so face economic hardship that can lead to depression, stress and a sense of helplessness. As landscapes are destroyed, one can expect a weaker sense of community and human connectedness to the land. One argument suggests that even accepting climate change as a threat could cause distress.
As with climate-related effects on physical health, the toll will be heaviest for those less able to cope with mental illness. Addressing the needs of people vulnerable to health risks will be key for preventing an unequal burden of climate-related effects, which some believe amounts to an ethical crisis.