Ms Frances Graham

5 December 2012

Latest research suggests that the predicted increase in heat-related extreme weather events as a result of climate change – in particular the infamous nor’wester wind in Christchurch – could pose a risk to the delivery of hospital services in the future.

Frances Graham, a senior adviser in the environmental and border health team at the Ministry of Health, examined Christchurch hospital data collected from 1990 to 2010 and climate data from the National Institute of Water and Atmospheric Research (NIWA) to determine the effects of heat-related extreme weather events, like the nor’wester wind, on heat-associated adverse health outcomes such as hospital admissions (morbidity).

This research, funded by the Health Research Council of New Zealand (HRC), is believed to be the first study in New Zealand to examine the relationship between environmental factors like climatic winds and the incidence of heat-induced conditions/illnesses.

Ms Graham took a research sabbatical to pursue this study with the help of the HRC’s Foxley Fellowship.

“The nor’wester is a particularly hot, dry and turbulent wind that results in a sudden increase in temperature and decrease in relative humidity,” says Ms Graham. “The city of Christchurch provided a unique location to examine the effects of the nor’wester on morbidity because of its location in the so-called nor’west belt.”

Preliminary results from Ms Graham’s research show that there was a six per cent increase in the number of people admitted to Christchurch Hospital for diabetes on hot days (≥25°C), including warm, windy days, and a 10 per cent increase in admissions for renal failure between 1990 and 2010. 

Abnormally hot days caused by climatic events like the nor’wester can increase the risk of developing a heat-related condition for those people with mental disorders, hyperthermia and chronic medical conditions such as diabetes. The thermoregulatory, physiological and circulatory adjustments necessary for the human body to cope with extreme heat can also place stress on the kidneys, predisposing patients to dehydration, heat exhaustion and heat stroke.

Ms Graham says modelling data from NIWA’s Dr Brett Mullan, a co-author of the study, along with input from climatologist Professor Glenn McGregor (The University of Auckland), shows that heat waves and other extreme heat-related events are expected to increase in both frequency and magnitude as climate change becomes more prominent. For the Canterbury region, the annual mean temperatures are predicted to increase 0.9°C from 1990 levels by 2040 and 2°C by 2090.

Based on her findings, Ms Graham believes that health providers and policy makers need to start taking preparations for climate change seriously.

“Global warming is changing our world dramatically and generating new risks.  Health providers and policy makers need to consider the science and begin applying it to the problem. In some circumstances, that will mean applying the same risk reduction approaches that emergency managers apply to natural disasters such as earthquakes.” 

The results from the study will now be used to assess the ability of Christchurch’s hospitals to deliver quality of care during hot days. Addressing heat exposure through urban planning, the design of new hospital facilities and changes to health education are some of the adaptive strategies being explored.

“Long-term health conditions such as diabetes and renal failure are forecast to continue to rise as New Zealand’s population ages. The question is how much the predicted average increase in temperatures will influence this,” says Ms Graham.