Once a day
Get Articles by e-mail:

Get Today's Climate by e-mail:

Climate Science Links

U.S. Government


Academic, Non-Governmental

Degree by Degree, Heat Waves Claim Lives, New Study Warns

For each 1 degree F rise in mean temperature and for each day a heat wave persisted, scientists found a 2.5 percent increased risk of death

by Joan Oleck

Nov 19, 2010

Record-breaking—and dangerous—heat waves have lately become a staple of summer. In Moscow last July and August during a tragedy that grabbed global attention, average mortality doubled, to 700 people a day. In Kuwait the temperature soared to 122 degrees. Temperatures in New York, Boston, and Philadelphia all hit 100 degrees Fahrenheit and set new daily highs as the U.S. National Oceanic and Atmospheric Association the warmest such period on record.

In China, intense heat actually caused a plague of locusts.

But while such events grab the headlines, even normal heat waves—the ones that make us run for air-conditioned homes and movie theaters—are dangerous. In fact, say two Yale University scientists, all heat waves pose public health risks more dangerous than most anyone has realized.

In in Environmental Health Perspectives, authors Michelle Bell and G. Brooke Anderson examined U.S. heat mortality data from different kinds of heat waves. They found that during all heat waves in 43 U.S. cities from 1987 to 2005, the average daily risk of death increased by an average 3.74 percent.

Further, they found that for each 1 degree Fahrenheit rise in mean temperature and for each day a heat wave persisted, there was a 2.5 percent increased risk of death.

“We think this is an issue that’s really important for the present day in terms of thinking about the public health burden of the heat waves,” Bell told SolveClimate News. “But also under a changing climate, this could be a public health problem that is exacerbated.”

What's a Heat Wave?

Bell, an associate professor of environmental health in the Yale School of Forestry & Environmental Studies (co-author Anderson is a postdoctoral fellow in the Environmental Engineering Program), said that the study defined a “heat wave” as two or more days with a mean temperature exceeding the 95th percentile for a city’s average May-to-September temperatures.

Deaths were considered “heat-related” if they were not accident-related, or suicides. Cardiovascular versus cardio mortality data were also reviewed. An important conclusion, Bell said, was that not all heat waves are alike.

“We looked at what are the characteristics of a heat wave that might modify its mortality risk,” she said. “[These were] the intensity, how hot was the heat wave, its duration, and its timing in summer.”

One interesting finding was that Southern heat waves weren’t nearly as devastating as those in the Northeast and Midwest.

“In locations where it’s more typically hot, such as in the South, we think that people may have acclimated to these conditions,” Bell said. Acclimation might mean biological adaption or behavioral and physical habits like using air conditioning or drinking more water.

Acclimation, she said, also might explain why heat waves in the early part of summer bring higher mortality: 5.04 percent vs. 2.65 percent at other times.

Catastrophic Heat Waves Still a Puzzle

The researchers also separately looked at catastrophic heat waves like the ones that struck Chicago and Milwaukee in the summer of 1995.  More than 500 Chicagoans died from heat-related causes over seven days (134 percent higher than the average heat wave mortality increase), as did 197 Milwaukee residents (93 percent higher) over 11 days.

The researchers wanted to see whether three heat wave characteristics--timing, duration and intensity--explained why those two 1995 events were so harmful. The answer, said Bell, is that the characteristics helped explain the harm, but not completely.

“There are clearly other things going on as well,” she said. “It could be some type of social network factors in terms of who has access to a safe place to be during a heat wave; it could be different types of interventions; our study was not able to determine what those factors are.”

Heat Wave

let me just say that i live in Greece and it's never been this hot, at least in my life time. It's almost December and it's worm out side.

Climate change

ho Hum..more alarmist warming nonsense. Most informed people, including many scientists around the world have come to realise that "global warming" and "climate change" are not in any way connected to C02. The IPCC have admitted fudging data to match their warming claims. Fraudulent Phil Jones made a revealing statement when he told Australian scientist Warwick Hughes in a 2005 email: "Why should I make the data available to you, when your aim is to try and find something wrong with it." And we thought the very basis of science was testing theories - but apparently no when it comes to global warming!! The fact is there is a powerful political agenda behind the "global warming" farce to allow greedy governments to create new "gravy train" taxes. Then there's the socialist agenda - how can one take the IPCC seriously when the founder admits his political bias??
“Isn’t the only hope for the planet that the industrialized civilizations collapse? Isn’t it our responsibility to bring that about?” – Maurice Strong, founder of the UN Environment Programme.
But perhaps the most damming quote is this one -
Climate policy has almost nothing to do any more with environmental protection, says the German economist and IPCC official Ottmar Edenhofer. The next world climate summit in Cancun is actually an economy summit during which the distribution of the world’s resources will be negotiated. – Ottmar Edenhofer

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Allowed HTML tags: <p> <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd> <img> <h1> <h2> <h3> <ul> <li> <ol> <b> <i> <p> <br>
  • Lines and paragraphs break automatically.
  • Youtube and google video links are automatically converted into embedded videos.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Images can be added to this post.

More information about formatting options