AoW #_______
Name _______________
Period_______________
Date ________________
Directions:
1.) Read the article.
2.) Reread the article. As you reread it, highlight parts that confuse you. Show
evidence of a close reading by marking up the text with questions and comments.
3.) Write a two paragraph reflection on your own sheet of paper, and staple your
reflection to this article.
Urban Heat Island Effect And Climate Change May Cause Scorching
City Temperatures
By Michael D. Lemonick
08/15/2012
For scientists who worry about climate change, cities are just plain annoying. The
acres of asphalt that cover roads and parking lots and roofs absorb enormous amounts
of heat. In the summer, whirring air conditioners channel even more heat out of
buildings and into the air. Climate scientists have to subtract this so-called urban heat
island effect from their calculations if they want to get a true picture of how greenhouse
gas emissions are warming the planet.
For people who actually live in cities, however the urban heat island effect is more
than just a mathematical annoyance. If you’re sweltering on a hot summer day, your
body doesn’t much care where the heat is coming from. And according to a paper just
published in Nature Climate Change, urbanization alone could drive local temperatures
up by a whopping 7°F by 2050 in some parts of the U.S. — some two or three times
higher than the effects of global warming (which would also be going on at the same
time).
“If you average this over the whole globe, the effect will be zero,” said lead author
Matei Georgescu, of Arizona State University, in an interview. “But people don’t care
about global temperatures. They care about conditions where they live.”
In this case, the people live in Arizona’s Sun Corridor, a megalopolis, or band of
urbanization, which stretches from the city of Nogales on the Mexican border to
Prescott, about 100 miles north of Phoenix. It’s one of the fastest-growing areas in the
country, with up to 16 million residents expected by 2050.
All those people will need roads and roofs and places to live, so Georgescu and
several colleagues wondered what the urban heat island effect of all that additional
population might be. They discovered that nobody had really thought much about it.
“This is an absolutely under-researched area,” Georgescu said, “and it deserves much
more attention.”
Georgescu and his team took urbanization maps created by Maricopa Association
of Governments and computerized weather prediction models that take the urban heat
island effect into account, and put them all together to figure out where local
temperatures might be heading. They focused on summer, when the urban heat island
effect is strongest, and when high temperatures can be downright deadly, especially to
the elderly who are already suffering from cardiovascular disease, lung diseases or
diabetes.
The danger is especially great when nighttime temperatures remain high, which
keeps the body from recovering after a scorching day. Unfortunately, the urban heat
island effect affects nighttime temperatures the most: that’s when all the heat absorbed
by the roads and buildings is re-released.
Georgescu emphasized that the 2050 scenario of a 7°F increase is the worst case:
if population growth is more restrained, or if urban planners keep local population
densities low and undeveloped open space relatively high, the effect could be much
less. Reining in emissions of greenhouse gases would also make a difference. And the
simple solution of replacing dark, heat-absorbing asphalt roof shingles with white,
reflective roofs could cut the projected temperature increase.
“It’s possible, it’s practical, and it could cut the projected temperature increase in
half,” Georgescu said. Unfortunately, he added, it doesn’t help at all with another
urbanization-related problem. When you pave or build over undeveloped land, you seal
in whatever moisture there is in the soil. It can no longer evaporate, which cuts off an
important source of humidity, and ultimately, of rain.
“So one of our take-home messages,” he said, “is that to be truly sustainable, you
can’t just focus on temperatures. The climate system isn’t only about warming.”
What is the author’s purpose?
What is the most surprising thing that you learned from this article?
Possible topics for your reflection:
 What other possible effects do you see as a result of “urban heat?”
 What are some possible solutions to this problem?
 Explain why you do/don’t think there is a solution to this problem.
 Should the government get involved in coming up with solutions to the problem?