Although heat is perhaps the biggest killer of all forms of weather, the threat is not always taken seriously, says the University of Michigan's Marie O'Neill. With climate change now likely to increase heat-related health risks, all local governments will need to know the best measures to ameloriate them.

"It's a moral, public health imperative to prevent the most vulnerable people from suffering due to weather," O'Neill told environmentalresearchweb.

O'Neill heads a project funded by the US Environmental Protection Agency that studies the association between heat and illness, to improve understanding of the risks. With heat-related mortality disproportionately affecting the poor and elderly, she also leads a similar project, funded by the US Centers for Disease Control and Prevention, that focuses on the links between heat, health and social disparity.

The Michigan team's epidemiological studies will collect daily data on deaths and hospital admissions and correlate these with weather conditions on that day and the few preceding. While such data have been collected before, O'Neill and her team are looking in greater detail at the contributory factors, and how successful different measures to reduce the health impact of heatwaves can be. As well as direct public health interventions, the researchers are also investigating how broader factors within cities, like tree planting and urban infrastructure, can keep homes and buildings cooler.

Yet, despite the risk from heat clearly being understood and financed at the highest level, O'Neill feels that some cities and states take it less seriously. "Just because the federal government chooses to fund our research, and we're trying to conduct it with a real connection to end users and policy makers, doesn't mean that the priority is high in every location," she noted.

Some, though, have made the connection between climate change and health, and are tackling the threat. "I think New York City is an example," O'Neill says. "Mayor Bloomberg is a real leader and he really has mobilized the city on climate-change issues, and health is part of that equation, but there are other places where that's not so much on the radar."

The variation in US administrations' efforts to tackle this problem will however provide useful data on which approaches work best. "Some of them have a formal heatwave warning system," O' Neill explained. "When there's a health advisory it might trigger opening of cooling centres where people who don't have access to air conditioning could go. Some of the cities have a buddy system, where elderly people or people living alone are checked on, either by neighbours or social-service agencies. Some of the cities, like Phoenix, Arizona, where it's really, really hot, have water distribution."

However O'Neill warns that at present these efforts are sporadic. "It's spotty in terms of which cities actually have a heatwave response programme that goes beyond just issuing a health advisory," she said. "I think there are areas for improvement in that."