Study links urbanization and future heat-related mortality
TEMPE, Ariz. – Phoenix stands at a parched crossroads. Global scale climate change is forecast to bring hotter summers and more extreme heat to the Valley, but regional urbanization also will impact temperatures experienced by residents.
So how should Phoenix grow knowing that such growth could cause temperatures to increase in the future and bring added health risks? Should the city deploy mitigating technologies to help fight summer’s heat? Would adopting a low-growth strategy reduce the adverse health consequences of hot weather?
New Arizona State University research examines the heat-health aspects resulting from urbanization and the challenge of sustainable future growth in Maricopa County. A study released this week shows how urban development could be a factor in the number of lives lost due to heat in future summers. The study is described in the article, “Challenges associated with projecting urbanization-induced heat-related mortality” published in the current online issue of the journal Science of the Total Environment.
“Extreme heat is the leading weather-related killer in the United States,” said David Hondula, a postdoctoral scholar in health informatics in ASU’s Center for Policy Informatics and lead author of the study. “In Maricopa County, we see more than 100 premature deaths and hundreds of excess emergency department visits as a result of high temperatures each summer. Understanding how different urban development strategies will impact the health risks associated with heat can help long-term planners and public officials make more informed decisions that lead to sustainable and healthy cities.”
In the research, the team tried to quantify the number of excess deaths attributed to heat in Maricopa County based on three future urbanization and adaptation scenarios and multiple exposure variables. Two scenarios (low and high growth projections) represent the maximum possible uncertainty range associated with urbanization in central Arizona; a third represents an adaptation strategy by simulating the deployment of white roof technology to the area.
The researchers – in addition to Hondula included Matei Georgescu and Robert C. Balling Jr., both of ASU’s School of Geographical Sciences and Urban Planning – related temperature to mortality using historical data from 1983 to 2007. Regional climate model simulations based on 2050-projected urbanization scenarios for Maricopa County generated distributions of temperature change, and from these changes in future excess heat-related mortality was estimated. They studied Maricopa County because it is a fast growing metropolitan area situated in a semi-arid region that experiences “chronic” heat during the summer months.
Overall, projections of heat related mortality ranged from a decrease of 46 deaths per year (-95 percent) to an increase of 339 deaths per year (+359 percent). Projections based on minimum temperature showed the greatest increase for all expansion and adaptation scenarios and were substantially higher than those for daily mean temperature. Projections based on maximum temperature were largely associated with declining mortality. Low growth and adaptation scenarios led to the smallest increase in predicted heat related mortality based on mean temperature projections.
Because of the environment in which it is built, increases in overnight minimum temperatures in Maricopa County associated with urbanization were found to be of much greater concern for health impacts compared to increases in daytime maximum temperatures. The same would be true in many other cities located in semi-arid regions.
“Future urbanization will lead to slightly lower summer daytime maximum temperatures in the urban core of Maricopa County compared to the surrounding natural landscape, because of the high heat retaining capacity of the built environment,” Matei Georgescu said. “Continued growth would enhance this effect in the future leading to further declines in daytime highs and associated declines in health risks. The tradeoff is that nighttime temperatures increase significantly with urbanization, and this nighttime warming is much greater than the expected daytime cooling.”
Hondula added that what this means for planners is that because heat impacts vary from day to night, projections of heat related health outcomes that do not consider place-based, time varying urban heat island effects are “neglecting essential elements for policy relevant decision-making.”
“The manner in which the Sun Corridor develops over the next several decades will impact the regional climate and, if no new adaptation measures are introduced, change the health risks for Maricopa County residents associated with extreme heat,” Hondula said. “The greatest health concern comes from large expected increases in nighttime temperatures which could be mitigated by lower-growth scenarios.”
“The next step is to look more closely at the conditions people experience on hot days, to ultimately determine if high maximum temperatures, minimum temperatures, or some combination of the two is the real culprit leading to adverse health events,” he added.
I have a simple test for the AZ researchers, we will put them out in the Arizona desert this time of year in a pair of shorts, with plenty of water. There is no chance they will die. I will put them in the north woods in January I will pick a below zero weather make no matches in a pair of shorts yet plenty of water, They would not last and much more than hour. If they want to stick to their claim heat kills more people I suggest they take my test. It would fix two problem at once falsify there guess, and eliminate some idiots or basic dishonest people from the face of the earth. If they are not willing to take the test that will also falsify their guess.
How do they cope in Africa and the Middle East? And Outback Australia?
Tanya Aardman says:
June 2, 2014 at 10:09 pm
How do they cope in Africa and the Middle East? And Outback Australia?
They all emigrate to the UK.
Pneumonia and influenza are the only weather related major cause of death in the US. Neither of these peak in the summer.
If hot weather is bad, why is the US population moving south and west? Why is Texas the fastest growing large state?
Why do almost all Canadians live within 150 miles of the southern border of Canada, leaving thousands of miles of empty land to the north?
Why are Mexican not dying by the millions due to heat? Their climate is even hotter than the US. And what about Africa? Surely Africans must be dying by the billions of heat?
we will put them out in the Arizona desert this time of year in a pair of shorts, with plenty of water. There is no chance they will die.
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they might die of UV if they are not sun adapted.
However, you are quite correct. The fatal temperature for unprotected humans is about 80F/27C (coincidentally, the temperature of the tropical jungles). Below that temperature you cannot generate enough heat to maintain your body temperature and will eventually die of exposure.
The critical issues is cost. All that is required to cool a human is water, which is low cost. However, to warm a human takes energy, which is high cost and becoming higher. What this means is that the combination of cold and poverty is fatal.
Unfortunately, simplistic research that does not take poverty into account when calculating mortality rates leads to false conclusions.
we will put them out in the Arizona desert this time of year in a pair of shorts, with plenty of water. There is no chance they will die.
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in the desert they might die of cold over-night. they will most certainly be miserably cold, wishing the sun was up. so long as they find some shade and have water they will be comfortable during the day.
Should the city deploy mitigating technologies to help fight summer’s heat?
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In Asia they use water misting. As the mist evaporates it sucks 550 kcal of energy out of the air for every 1 liter of water. Add water misters to the outside of every building in Phoenix and you could probably drop the temperature of the city by 10 degrees in summer. The cost would be negligible. No electricity required. Water and plastic piping.
Of course, almost as simple is to allow people to water their lawns in summer during the day. Water restrictions on watering lawns and gardens most certainly makes summertime temperatures higher. If you are too hot try standing under a lawn sprinkler. You will not be too hot for long.
@ferdberple
They do that in Palm Springs. And it really makes it pleasant to stroll around town.
ferdberple says:
June 3, 2014 at 6:11 am
You lost me there. It’s my understanding that fatal (body) temperature is about 105F/40C
ferdberple also says:
June 3, 2014 at 6:13 am
WU forecast: Tucson AZ for 6/3/2014
High: 107F
Low: 75F
http://www.wunderground.com/cgi-bin/findweather/getForecast?query=tucson+az
Here in the SW American desert, summer nights are delight.
s/b: a delight, or delightful.
On a hot summer day, the interior of a vehicle parked in the sun can approach 150F:
http://www.kten.com/story/14907911/car-interiors-can-exceede-temperatures-of-150-degrees-during-summer
And then, there are these folks:
http://en.wikipedia.org/wiki/Polar_bear_plunge
It is so easy to be of a Global Warmist. If the facts don’t suit, make up some figures which do. Now that is what they (note: they) call science. If we are damned now, in another 25 years what will they be doing/saying?
A little tune about water in the desert, the Kingston Trio’s
Desert Pete