Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research reveals the give and take of urban temperature mitigating technologies

10.02.2014
Life in a warming world is going to require human ingenuity to adapt to the new realities of Earth.

Greenhouse-gas induced warming and megapolitan expansion are both significant drivers of our warming planet. Researchers are now assessing adaptation technologies that could help us acclimate to these changing realities.


The deployment of cool roofs, roofs typically painted white, help mitigate summertime temperatures but in Florida and some Southwestern cities like Phoenix (pictured) the roofs also have a negative effect on rainfall.

Credit: Ken Fagan, Arizona State University

But how well these adaptation technologies – such as cool roofs, green roofs and hybrids of the two – perform year round and how this performance varies with place remains uncertain.

Now a team of researchers, led by Matei Georgescu, an Arizona State University assistant professor in the School of Geographical Sciences and Urban Planning and a senior sustainability scientist in the Global Institute of Sustainability, have begun exploring the relative effectiveness of some of the most common adaptation technologies aimed at reducing warming from urban expansion.

The work showed that end-of-century urban expansion within the U.S. alone and separate from greenhouse-gas induced climate change, can raise near surface temperatures by up to 3 C (nearly 6 F) for some megapolitan areas. Results of the new study indicate the performance of urban adaptation technologies can counteract this increase in temperature, but also varies seasonally and is geographically dependent.

In the paper, "Urban adaptation can roll back warming of emerging megapolitan regions," published in the online Early Edition of the Proceedings of the National Academy of Sciences, Georgescu and Philip Morefield, Britta Bierwagen and Christopher Weaver all of the U.S. Environmental Protection Agency, examined how these technologies fare across different geographies and climates of the U.S.

"This is the first time all of these approaches have been examined across various climates and geographies," said Georgescu. "We looked at each adaptation strategy and their impacts across all seasons, and we quantified consequences that extend to hydrology (rainfall), climate and energy. We found geography matters," he added.

Specifically, what works in California's Central Valley, like cool roofs, does not necessarily provide the same benefits to other regions of the U.S., like Florida, Georgescu said. Assessing consequences that extend beyond near surface temperatures, like rainfall and energy demand, reveals important tradeoffs that are oftentimes unaccounted for.

Cool roofs are a good example. In an effort to reflect incoming solar radiation, and therefore cools buildings and lessen energy demand during summer, painting one's roof white has been proposed as an effective strategy. Cool roofs have been found to be particularly effective for certain areas during summertime.

However, during winter these same urban adaptation strategies when deployed in northerly locations, further cool the environment and consequently require additional heating to maintain comfort levels. This is an important seasonal contrast between cool roofs (i.e. highly reflective) and green roofs (i.e. highly transpiring). While green roofs do not cool the environment as much during summer, they also do not compromise summertime energy savings with additional energy demand during winter.

"The energy savings gained during the summer season, for some regions, is nearly entirely lost during the winter season," Georgescu said.

In Florida, and to a lesser extent Southwestern states of the U.S., there is a very different effect caused by cool roofs.

"In Florida, our simulations indicate a significant reduction in precipitation. The deployment of cool roofs results in a 2 to 4 millimeter per day reduction in rainfall, a considerable amount (nearly 50 percent) that will have implications for water availability, reduced stream flow and negative consequences for ecosystems," he said. "For Florida, cool roofs may not be the optimal way to battle the urban heat island because of these unintended consequences."

Georgescu said the researchers did not intend to rate urban adaptation technologies as much as to shed light on each technology's advantages and disadvantages.

"We simply wanted to get all of the technologies on a level playing field and draw out the issues associated with each one, across place and across time."

Overall, the researchers suggest that judicious planning and design choices should be considered in trying to counteract rising temperatures caused by urban sprawl and greenhouse gasses. They add that, "urban-induced climate change depends on specific geographic factors that must be assessed when choosing optimal approaches, as opposed to one size fits all solutions."

Source:
Matei Georgescu, (480) 727-5986
Media contact:
Skip Derra, (480) 965-4823; skip.derra@asu.edu

Skip Derra | EurekAlert!
Further information:
http://www.asu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Traffic emissions may pollute 1 in 3 Canadian homes
22.04.2015 | University of Toronto Faculty of Applied Science & Engineering

nachricht Engineers purify sea and wastewater in 2.5 minutes
17.04.2015 | Investigación y Desarrollo

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fast and Accurate 3-D Imaging Technique to Track Optically-Trapped Particles

KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.

Daejeon, Republic of Korea, April 23, 2015--Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and...

Im Focus: NOAA, Tulane identify second possible specimen of 'pocket shark' ever found

Pocket sharks are among the world's rarest finds

A very small and rare species of shark is swimming its way through scientific literature. But don't worry, the chances of this inches-long vertebrate biting...

Im Focus: Drexel materials scientists putting a new spin on computing memory

Ever since computers have been small enough to be fixtures on desks and laps, their central processing has functioned something like an atomic Etch A Sketch, with electromagnetic fields pushing data bits into place to encode data.

Unfortunately, the same drawbacks and perils of the mechanical sketch board have been just as pervasive in computing: making a change often requires starting...

Im Focus: Exploding stars help to understand thunderclouds on Earth

How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was discovered, more or less by coincidence, that cosmic rays provide suitable probes to measure electric fields within thunderclouds. This surprising finding is published in Physical Review Letters on April 24th. The measurements were performed with the LOFAR radio telescope located in the Netherlands.

How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was...

Im Focus: On the trail of a trace gas

Max Planck researcher Buhalqem Mamtimin determines how much nitrogen oxide is released into the atmosphere from agriculturally used oases.

In order to make statements about current and future air pollution, scientists use models which simulate the Earth’s atmosphere. A lot of information such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

HHL Energy Conference on May 11/12, 2015: Students Discuss about Decentralized Energy

23.04.2015 | Event News

“Developing our cities, preserving our planet”: Nobel Laureates gather for the first time in Asia

23.04.2015 | Event News

HHL's Entrepreneurship Conference on FinTech

13.04.2015 | Event News

 
Latest News

Electrons Move Like Light in Three-Dimensional Solid

24.04.2015 | Materials Sciences

Connecting Three Atomic Layers Puts Semiconducting Science on Its Edge

24.04.2015 | Materials Sciences

Understanding the Body’s Response to Worms and Allergies

24.04.2015 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>