Predictions of a balmy El Niño summer in New Zealand have sparked a warning about vigilance in the water to avoid drownings reaching another unwanted high.

A new international research collaboration has shown a strong correlation between hotter temperatures and an increase in drowning fatalities, says Dr Matt Hobbs, a member of the research group and a Senior Lecturer in Te Whare Wānanga o Waitaha | University of Canterbury’s Faculty of Health.

“New Zealand already has a high drowning death toll per capita compared to other countries such as Australia and Canada," says Dr Hobbs, who is also a co-director of UC’s GeoHealth Laboratory.

"With the El Niño summer, we want to make sure people are really aware of the dangers and take extra care in and on the water,.

“Previously we’ve shown that particular locations in the United Kingdom are more common for drownings.

"We’re now working on a new, international study, currently under review, showing how increases in temperature correlate with an increase in drownings.

"If the predicted hot summer eventuates here, there will be more people in the water, increasing the danger. This is going to become even more of an issue in future years with the impact of climate change."

New Zealand has had a drowning rate of 1.7 per 100,000 for the past 10 years. Australia’s rate is 1.1 per 100,000 and Canada’s is 1.3.

In 2022, there were 94 preventable drowning deaths in New Zealand, and in 2021 there were 91 deaths, pushing the drowning rate to the highest in a decade.

By early December 2023, there had already been 82 deaths this year, including six due to Cyclone Gabrielle in February, according to provisional Water Safety NZ figures.

Dr Hobbs recently attended the World Conference on Drowning Prevention in Perth, Australia where, as part of an international delegation, he presented the findings from a study he led investigating drowning fatalities in the United Kingdom between 2012 and 2019. The research identified locations that are high frequency or “hotspots” for drownings.

He says New Zealand, and other countries around the world, especially those that are low or middle income, would benefit from similar research using geospatial methods to highlight high or very high-risk locations for drownings, and identify environmental contributors to this elevated risk.

This information would provide an important foundation for population-level drowning prevention interventions, such as educating people about the risks of alcohol consumption before going into water or providing signage warning about local water hazards.

“For instance, geospatial data might be able to tell us if the people who are drowning are local and familiar with local features such as where rips are on beaches, or if they’re visitors from elsewhere who don’t know the risks, so we can target interventions accordingly,” says Dr Hobbs.

“While our geospatial data can’t always say why these drownings occur, it is an important first step to know where people are drowning. From there we can have discussions with the community and partners working on the ground to identify why such areas may be high frequency drowning locations.”

Water Safety NZ data shows New Zealand men made up 85 per cent of drowning fatalities in 2022, with men aged over 55 at higher risk.

According to World Health Organisation figures, there were an estimated 236,000 drowning deaths worldwide in 2019, making it a major public health problem.